1
Digestion and Absorption
01.
Introduction
3
02.
Mouth & buccopharyngeal cavity
5
03.
Teeth
7
04.
Oesophagus and Stomach
8
05.
Intestine
06.
Alimentary canal
07.
Digestive gland
08.
Physiology of digestion
09.
Assimilation of food
29
10.
Disorders of digestive system
30
11.
Vitamins
33
12.
Exercise-I (Conceptual Question)
38
13.
Exercise-II (Previous Years Questions)
46
14.
Exercise-III (Analytical Questions)
48
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NEET SYLLABUS
Digestion and Absorption : Alimentary canal and digestive glands; Role of digestive enzymes and gastrointestinal hormones;
Peristalsis, digestion, absorption and assimilation of proteins, carbohydrates and fats; Caloric value of proteins, carbohydrates
and fats; Egestion; Nutritional and digestive disorders – PEM, indigestion, constipation, vomiting, jaundice, diarrhea.
2
DR. D. NAGESHWAR REDDY
MD.,DM.,D.SC.,FAMS.,FRCP.,FASGE.,FACG.,MWGO
Chief of Gastroenterology & Therapeutic Endoscopy
Medical College M.B.B.S. Kurnool Medical College, KURNOOL
Specialisation M.D. Madras Medical College, MADRAS
Specialization in Gastroenterology D.M.
Post Graduate Institute of Medical
Education and Research, CHANDIGARH
Professional ExperienceAsst. Professor of Gastroenterology Nizam's
Institute of Medical Sciences, Hyderabad
Professor of Gastroenterology Guntur Medical College, Guntur
Present Position Chairman Asian Institute of Gastroenterology Areas
of InterestGastroenterology
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DR. RAMESH ROOP RAI is a well experienced and senior consultant
Gastroenterologist associated with Fortis Hospitals, Jaipur. He is the first
DM Gastroenterologist in Rajasthan, he worked in various projects and
has published over 98 research papers in National & International
Journals. He has been instrumental in designing and manufacturing for
various procedures of Gastroenterology. Dr. Ramesh was elected as the
president of Indian Society of Gastroenterology 2007-2008, he was a
pioneer to start first DM course in Gastroenterology SMS Medical College,
Jaipur.
Over the years, DR. RAKESH TANDON has won many discrete awards
for his contribution, hard work and commitment towards providing patients
a new lease of life.Dr. Rakesh Tandon has been awarded by the Medical
Council of India, has Dr. B.C.Roy Award for being Eminent Teacher, Gold
medal for best thesis in M.D. (Medicine) and many more. Dr. Rakesh
Tandon publications are read all over the world because he is not restricted
to writing for only Indian audiences. Dr. Rakesh Tandon has authored
some well known and bestselling books.
Dr. Rakesh Tandon has MBBS, MD (General Medicine), done PhD from
AIIMS, FAMS, FICP and FRCP from Royal College of Surgeons,
Edinburgh, UK. This clearly shows he has superior knowledge and uses
it well in every medical issue that Dr. Rakesh Tandon deals with. His creative
ideas have helped patients enormously.
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DIGESTION AND ABSORPTION
Food is one of the basic requirements of all living organisms. The major components of our food are
carbohydrates, proteins and fats. Vitamins and minerals are also required in small quantities. Food provides energy
and organic materials for growth and repair of tissues. The water we take in, plays an important role in metabolic
processes and also prevents dehydration of the body. Biomacromolecules in food cannot be utilised by our body in
their original form. They have to be broken down and converted into simple substances in the digestive system. This
process of conversion of complex food substances to simple absorbable forms is called digestion and is carried out by
our digestive system by mechanical and biochemical methods.
Parotid gland
Mouth
Submaxillary gland
21
Sublingual gland
Oesophagus
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Diaphragm
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Stomach
io
Liver
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Pancreas
Jejunum
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Gall bladder
Common bile duct
Duodenum
Left colic flexure
Right colic flexure
Transverse colon
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Ascending
colon
E
Descending colon
Jejunum
ileum
Pelvic (sigmoid) colon
Caecum
Rectum
Appendix
Anal canal
Digestive tract of Human
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Oral cavity
Parotid gland
Pharynx
Mouth
Submaxillary and
sublingual glands
Oesophagus
Liver
Gall bladder
Stomach
Duodenum
Transverse colon
Ascending colon
Ileum
Caecum
Vermiform
appendix
Pancreas
Jejunum
Descending colon
Sigmoid colon
Rectum
Anus
The human digestive system
21
Origin of alimentary canal
*
The alimentary canal is tubular structure which extends from mouth to anus. It develops from ectoderm &
endoderm.
Ectoderm - upto hard palate
Endoderm - from soft palate to rectum
Ectoderm - from anal canal to Anus
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DIGESTIVE SYSTEM
The human digestive system consists of the alimentary canal and the associated glands.
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ANATOMY OF ALIMENTARY CANAL
Salivary glands
Intestine
Bucco Oesophagus Stomach
Gastric glands
pharyngeal
Cardiac
chamber
Small
Large
Intestinal glands
Fundus
Caecum
Duodenum
Liver
Body
Colon
Jejunum
Pylorus
Pancreas
Rectum
Ileum
Oral vestibule
C
contain
tongue
Opens into anus
O
Buccal
N
teeth
cavity
S
palate
I
S
is of two types
T
O
F
Hard
divided
Pharynx
into
Soft
Nasopharynx
Oropharynx
Laryngopharynx
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Mouth
Digestive glands
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Alimentary canal
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Human digestive system
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Alimentary Canal
The alimentary canal begins with an anterior opening – the mouth, and it opens out posteriorly through the
anus.
(1)
Mouth and Buccopharyngeal Cavity –
Mouth is a horizontal transverse slit like aperture which is surrounded by upper and lower lip. Lips are movable
because of presence of muscles called orbicularis oris muscles.
*
Sebaceous glands are found on the outer part of lip. Serous glands are found on the inner part of lip. Serous
glands are the modification of mucus glands. Their secretory substance is watery.
*
The mouth leads to the buccal cavity.
(i)
Buccal vestibule – The space between the gums and cheeks where the food is stored temporarily.
(ii)
Oral cavity – The oral cavity has a number of teeth, a muscular tonque and palate. It is inner & central
part which is surrounded by upper and lower jaw. Lined by non keratinized stratified squamous epithelium.
Upper Jaw is fixed and lower jaw is movable.
The roof of oral cavity is called Palate.
Hard Palate –
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(i)
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Palate is differentiated into two parts :
It is the anterior part of the palate. It is made up of maxilla and palatine bone in human.
*
On the ventral surface of hard palate, some projections or transverse ridges are present which are called
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palatine rugae.
(ii)
Soft Palate –
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in carnivorous animals.
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These rugae prevent slip out of the food from buccal cavity during mastication. These rugae are well developed
It is the posterior part of palate.
*
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Soft palate
The posterior out growth of soft palate which
hangs down in the form of finger like process
E
Nasal Chamber
Hard palate
Nasopharynx
Eustachian tube
called as Uvula or Velum palati. On the
dorsal side of uvula one pair internal nasal
pores are present.
Uvula or Velum palati covers the opening
of internal nasal pores during ingestion of
food, so food particle can not move inside
nasal chamber.
*
Oral cavity
Tongue
Uvula
Oropharynx
Larynx
Trachea
Laryngopharynx
Oesophagus
Diagram showing parts of pharynx
One pair of large lymph node is present on the posterolateral surface of soft palate, called as Palatine tonsil
or Tonsils.
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*
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Soft palate is situated in the pharynx and is divided into two parts. Upper part of pharynx is called Nasopharynx
which is related to the nasal chamber. The lower part of pharynx is called oropharynx which is related to the
oral cavity. One pair of openings of Eustachian tube is present in the nasopharynx. This Eustachian tube is
related to the middle ear : It maintain air pressure.
The oral cavity leads into a short pharynx which serves as a common passage for food and air. The oesophagus
and the trachea (wind pipe) open into the pharynx. A cartilaginous flap called epiglottis prevents the entry of
food into the glottis – opening of the wind pipe – during swallowing.
TONGUE :–
The tongue is a freely movable muscular organ attached to the floor of the oral cavity by the frenulum. The
upper surface of the tongue has small projections called papillae, some of which bear taste buds.
Lingual tonsil
Pharyngeal
part of tongue
Foramen caecum
Sulcus terminalis
CircumVallate papillae
Foliate papillae
Oral
part of tongue
Filiform papillae
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Deficiency of vitamin B2 causes cheilosis, Glossitis, Keratitis.
The two limbs of the 'V' meet at a median pit named Foramen caecum.
It is divided into two parts –
(I)
Pharyngeal part – It is the posterior 1/3 part of the tongue. Many small lymph nodes are present in
this part which are called Lingual tonsil.
(II) Oral or papillary part – It is anterior 2/3 part of tongue. Four types of papillae are found in this part
in which gustatory or taste receptors are present in the form of taste buds with few papilla.
(i)
Fungiform Papillae –
It is pink coloured, small & spherical in shape. It is found on the entire surface of tongue but mostly
present at the anterior part of tongue. It is attached to tongue with the help of small pedicle. It provides
pink colour to the tongue.
(ii)
Filliform papillae (Conical papillae ) –
They are thread like, white coloured & conical in shape. They are also found on the entire surface of
tongue. They are most numerous, but devoid of taste buds.
(iii) Foliate papillae –
They are found on the mid lateral surface of tongue. They are vestigeal in the human. There structure is
leaf like present in rabbit and other mammals.
(iv) Circumvallate papillae –
These are largest and least existed papillae (8 to 12). They are large spherical shape papillae which are
found near to sulcus terminalis.
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Tongue is nonmotile in whale.
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*
On the floor of oral cavity a muscular, flat, fleshy plate like structure is present which is called tongue.
The anterior part of tongue is free while posterior part of tongue is connected to the Hyoid bone.
On the dorsal surface of tongue, it is divided into two unequal parts by a V shaped sulcus, called sulcus terminalis.
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Upper surface of human tongue
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Fungiform papillae
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Two types of muscles present in tongue :Extrinsic muscles :*
It is found on outer and superficial part of tongue. It helps in outward and inward movement of tongue.
Intrinsic muscles :*
It is situated in the deep part of tongue. It helps in the change of shape of tongue and sideways movements of
tongue.
TEETH
*
Teeth are ectomesodermal in origin.
In human beings three basic features of teeth are Thecodont, diphyodont, heterodont
Each tooth is embedded in a socket of jaw bone. This type of attachment is called thecodont
Majority of mammals including human being forms two sets of teeth during their life, a set of temporary milk or
deciduous teeth replaced by a set of permanent or adult teeth. This type of dentition is called diphyodont. An
adult human has 32 permanent teeth which are of four different types (Heterodont dentition), namely, incisors
(I), canine (C), premolars (PM) and molars (M). Arrangement of teeth in each half of the upper and lower jaw in
the order I, C, PM, M is represented by a dental formula which in human is
2123
. The hard chewing surface
2123
of teeth, made up of enamel, helps in the mastication of food.
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Four types of teeth found in mammals are -
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Incisor- These are long, chisel like teeth for gnawing the food. They are more developed in gnawing animals
e.g. Lagomorphs, rodents.
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Tusk of elephant are modification of upper incisor.
Tusk is used to protection from enemies, attack on enemies (not for feeding purp ose).
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Canines- These are sharp pointed teeth meant for tearing and shreding the food. Canines are most developed
in carnivorous animals.
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Canines are absent in herbivorous animals e.g. Rabbits do not have canines. In h erbivorous,
the space of canine in gums is empty and this empty space is called diastema.
Upper canines are modified in tusks in walrus.
Pre molars - These teeth are meant for chewing and crushing of food. They are triangular in shape.
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Molars (Cheek teeth) – These also meant for chewing & crushing of food. They are rectangular in shape.
E
*
In mammals, except Premolar and Last molar, all type of teeth appear twice in life. Teeth which appear during
childhood are called milk teeth/temporary teeth/lacteal teeth/deciduous teeth/primary teeth. Due to
the activity of osteoclast cells milk teeth are shed, then permanent teeth appear.
*
When temporary molars shed, their socket are filled by premolar and new socket are formed for permanent
molar. This occurs once in life time.
*
In frog, only upper jaw has teeth.
*
Hippocampus, tortoise and birds do not have teeth.
In humans, premolar teeth appear in the alveoli of molar teeth while permanent molar teeth are developed in
new alveoli.
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HUMAN DENTITION :- Arrangement of teeth on jaws is dentition. Human dentition has following features.
(1)
(A) Monophyodont :- The teeth which appear only once in life. eg. Premolars and last molars of human.
(B) Diphyodont :- The teeth which appear twice in life. eg. Incisors, Canines, 1st and 2nd molars.
(2)
Thecodont :- The teeth which are present in bony socket of Jaw. eg. Human and Crocodile.
(3)
Heterodont :- When the teeth are of different type in mammals on the basis of structure and function.
Dental formula :Child
=
Incisor
2 1
0 2 5
10
= 20
I C PM M = ´ 2 =
0 2 5
10
2 1
Canine
Premolars
17 Yr. old
=
2 2 7
2 1
I C PM M = ´ 2 = 28
2 1
2 2 7
Adult
=
2 1
2 3 8
16
I C PM M = ´ 2 =
= 32
2 3 8
16
2 1
Molars
Socket
of jaw
Arrangement of different types of
teeth in the jaws on one side and
the sockets on the other side
Florine maintain enamel and checks dental decay.
Vitamin C deficiency causes scurvey in which bleeding gums and loose teeth like symptoms appears.
P and Ca is component of Bone and teeth and Ca is essential for normal blood clotting.
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Ca deficiency causes rickets and muscular spasm.
02
ALIMENTARY CANAL
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OESOPHAGUS –
Two apertures are found in Buccopharyngeal cavity.
Ventral aperture is called Glottis which is related to the larynx which is guarded by epiglottis.
*
The dorsal aperture is called gullet which opens into oesophagus.
*
The oesophagus is a thin, long tube which extends posteriorly passing through the neck, thorax and diaphragm
and leads to a ‘J’ shaped bag like structure called stomach. A muscular sphincter (gastro-oesophageal) regulates
the opening of oesophagus into the stomach. The oesophageal hiatus is an opening in the diaphragm through
which the oesophagus and the vagus nerve pass.
*
In oesophagus digestive glands are absent, only mucous glands are present in mucosa and submucosa.
*
The length of oesophagus depends on length of neck so the longest Oesophagus is present in Giraffe.
STOMACH
*
It is situated on left side of abdominal cavity. It is the widest part of alimentary canal. It is a bag like
muscular structure, J shaped in empty condition.
The stomach contains four parts (Cardiac, Fundus, Body, Pylorus) - A cardiac portion into which the oesophagus
opens, a fundus region, body main central region and a pyloric portion which opens into the first part of small
intestine.
It has two orifices (opening)
(i) Cardiac orifice is joined by the lower end of the oesophagus.
(ii) Pyloric orifice opens into the duodenum.
*
Stomach is covered by layer of peritoneum. Fat tissues and lymph tissue deposits on the peritoneum. Such type
of peritoneum are called Ommentum.
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Left curved surface of stomach is called greater ommentum. Right curved surface of stomach is called lesser
ommentum.
Hiatus
Cardiac orifice
Diaphragm
Pyloric
orifice
CA
Canal
AN
RU
Fun
dus
IAC
BODY
UM
LO
TR
PY
RD
S
Mucous membrane of the stomach is thick. In empty stomach numerous temporary longitudinal
folds are found in mucosa of stomach called rugae. They disappear when stomach is distended.
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Gastric Glands :- These are numerous microscopic, simple branched tubular glands formed by the invagination of epithelium in the stomach. The following types of cells are present in the epithelium of the gastric
glands.
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1. Mucous neck cells
Out of these four types of cells, 3 major types of cells are
(a) mucous neck cells (b) oxyntic or parietalcells
(c) Chief cells or peptic cells or zymogencells
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2. Entero endocrine cells
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4. Chief cells or peptic cells or Zymogen cells
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3. Oxyntic cells or parietal cells
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secrete
Mucous cells ¾¾¾® mucus - protect inner lining of stomach by action of HCl
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Consist of 4 types of cells
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Enteroendocrine cells
G-cells ¾® Gastrin - stimulate the secretion of gastric juice
D-cells ¾® Somatostatin
EC-cells ¾® Serotonin - Vasoconstrictor
¾® Histamine - Vasodilator
Parietal cells ¾® Castle Intrinsic Factor - helps in absorption of vitamin B 12.
(Oxyntic cells) ¾® HCl (pH = 2 to 3) (1) inactivate ptyaline
(2) Kill bacteria present in bolus
(3) Convert inactive enzymes into active enzymes
(4) Provide acidic medium in stomach
(5) Softens food particles
(Peptic cells)
Chief cells
(Zymogen cells)
Gastric amylase (negligible role in starch digestion)
Gastric lipase - convert 1% emulsified fats already present
in our food into fatty acids and glycerol
Pepsinogen
Prorennin
(In infants)
Pepsin
HCl
Rennin
Proteins
Soluble milk protein casein
Insoluble Ca-paracaseinate
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INTESTINE
It is divided into two part
(i) Small intestine
(ii) Large intestine
SMALL INTESTINE
*
Small intestine is distinguishable into three regions, a ‘C’ shaped duodenum, a long coiled middle portion
jejunum and a highly coiled ileum. The opening of the stomach into the duodenum is guarded by the pyloric
sphincter.
*
For absorption of digested food a very large surface area is required. Therefore some adaptations are present
here.
(a) Great length of the intestine.
(b) Villi and microvilli.
(c) Plicae circulares (valves of Kerckring) (valvulae conniventes)
LARGE INTESTINE
Ileum opens into the large intestine.
*
Large intestine (Larger in diameter) – Large intestine is differentiated into three parts caecum, colon and
rectum.
*
The lower end of the ileum opens on the Posteromedial aspect of the Ileo-caecal junction. The Ileocaecal
opening is guarded by Ileocaecal valve. Caecum is a small blind sac. Which hosts some symbiotic
microorganisms.
*
About 2 cm below the ileocaecal orifice, a worm like structure arises from the caecum called as vermiform
appendix.It is a vestigeal organ. Caecum is well developed in rabbit and other mammals but is vestigeal in
human.
COLON
*
Caecum continues in colon, which is the middle part of large intestine.
*
The longitudinal muscle coat forms three ribbon like bands called Taeniae coli. Due to the presence of taeniae,
pouch like structure develops in Lumen of colon called as Haustra. Colon has following parts in human – an
ascending, a transverse, descending part and a sigmoid or pelvic colon.
RECTUM
*
This colon then continues in a uniform tube called Rectum. (Storage chamber for faeces)
*
Rectum open into a small bag like structure called anal-canal.
ANAL – CANAL
*
Anal canal opens outside by anus. Anus is controlled by anal sphincter.
Two types of anal sphincter are found at the opening of anus..
*
Two types of sphincter muscles are found in Anal canal.
Internal Anal sphincter ¾® Involuntary
External Anal sphincter ¾® Voluntary
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BEGINNERS BOX-1
ANATOMY OF ALIMENTARY CANAL
Dental formula of adult man is (1)
13.
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E
(4) 11
(2) 22
(3) 32
(4) 12
(2) Glottis
(3) Epiglottis
(3) Glottis
The hardest constituent of the tooth is-
(4) Gullet
21
(2) Larynx
(3) Bone
(2) Acrodont
(3) Pleurodont
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Types of teeth in human -
(4) Pulp
(4) Homodont
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Posterior part of soft palate, hangs down in pharynx, called(2) Tonsils
(3) Velum Palati
(4) Jacobson's organ
(3) By palatine
(4) None of these
Nasal chambers and buccal cavity are seperated by(2) By palate
Cheek teeth are(1) Inscisors and Canines
(2) Canines and Premolars
(3) Premolars and Molar
(4) Canines and Molars
Presence of water amount in enamel is (2) 75 - 80 %
(3) 40 - 50 %
What do you mean by the process of digestion ?
(1) Conversion of complex substances into simpler form
(2) Absortion of monomers by the body
(3) Conversion of monomers into polymers
(4) Absorption of water and food
15.
(4) Pharynx
Which of the following is a common passage in swallowing food and breathing-
(1) 90 - 92 %
14.
(3) 8
The structure which prevents entry of food into wind pipe during swallowing in mammals is-
(1) By uvula
12.
(2) 3
(4) Epithelium being resistant to HCl
(1) Palatine
11.
(4) taeniae
(3) HCl being dilute
(1) Thecodont
10.
(3) zymogen cells
(2) Neutrilizatioin of HCl by alkaline gastric juice.
(1) Enamel
9.
2132
2132
(1) Mucus secretion covering the epithelium
(1) Pharynx
8.
(4)
The cells of the epithelial lining in the vertebrate stomach are not damaged by HCl because of-
(1) Larynx
7.
(2) crypts of lieberkuhn
io
6.
2123
2124
Number of teeth which are monophyodont in man is(1) 4
5.
(3)
pH of stomach in human is about(1) 7
4.
2123
2122
In Colon, constrictions of its wall form a series of small pockets called(1) haustra
3.
(2)
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2.
2123
2123
Se
1.
What is frenulum ?
(1) It is the fold by which tongue is attached to the floor of oral cavity.
(2) It is an adenoid which is present on pharyngeal wall
(3) It is a tonsil like structure on the lateral walls of palate
(4) It is V-shaped furrow which divides the surfaces of tongue
(4) » 3 %
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HISTOLOGY OF ALIMENTARY CANAL
Unilayered Epithelium in Stomach, duodenum, jejunum, ileum
Simple columnar
Simple columnar glandular Scgbbe form
glandular epithelium form brush border Epithelium form Long-Pointed Villi
Blunt-Villi
Gastric Glands
Multilayered
Epithelium
Mucosa
Epithelium
Lamina Propria
of Reticular
Fibrous CT
Muscularis mucosa
Crypts of
Lieberkuhn
Circular
Longitudinal
Circular
Longitudinal
Circular
Longitudinal
Circular
Longitudinal
Paneth
cells
} Peyer's
patches
Muscularis
Layers
Brunner's
Submucosa of Areolar
Glands
CT rich in blood vessels,
Lymph vessels and
nerve fibres
Branches of Sympathetic and parasympathetic nerve fibres (Meissner's nerve plexus)
Oblique
Circular
Circular
Circular
Circular
Circular
Nerve Fibres
Branches of Sympathetic and parasympathetic nerve fibres (Auerbach nerve plexus)
Longitudinal
Longitudinal
Serosa-Made up of
simple squamous
epithelium or
mesothelium
Areolar + WFCT
called tunica adventitia
Longitudinal
Longitudinal
Longitudinal
SSE + Fats + Lymph
Tissues = Ommentum
Serosa
Serosa
Oesophagus
Stomach
Duodenum
Jejunum and Ileum
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Wall of alimentary canal is made up of four layer (outer to inner)
Serosa : It is outer most layer of gut (it is called tunica adventitia in oesophagus) serosa is made up of a
thin mesothelium (visceral peritoneum) with some connective tissue. Tunica adventitia is made up of
white fibrous connective tissue and areolar connective tissue.
(2)
Muscle layer : It is formed by circular inner layer and longitudinal outer layer of smooth muscle. Thickest
layer is found in stomach (maximum peristalsis) and thinest layer in rectum (minimum peristalsis).
(3)
Sub mucosa : It is loose connective tissue layer with blood vessels, lymph vessels and nerves.
(4)
Mucosa : It is the inner most layer of gut which contains the secretory and absorptive cells.
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It is differentiated into 3 parts.
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(1)
*
It is made up of longitudinal and circular muscles.
*
It has important role in exposing of surface area for the absorption
*
They also provide support to the folds of alimentary canal.
Middle part :- It's called lamina propria it contains few modified lymphatic tissue which provides immunity ex.
peyer's patches .
*
It is made up of reticulate and fibrous connective tissue.
Innermost part :- Called mucosal layer.
*
In oesophagus this layer is made up of non keratinised stratified squamous epithelium.
*
Except oesophagus this layer is single layer thick, which is made up of columnar mucous epithelium.
*
This layer makes the lining of lumen of Alimentary canal.
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Outer part :- Called mucosa muscularis.
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13
*
This layer makes the folds of alimentary canal.
*
Folds of oesophagus are less developed, whereas folds of stomach are finger shaped and develop as gland
called gastric gland.
*
Folds of small intestine are conical shaped called Villi. Small slit like space is found at the base of villi. These
spaces are called crypts of Lieberkuhn
*
Villi of duodenum are small blunt.
*
Villi of Jejunum and Ileum are long and pointed.
*
Maximum villi are found in Jejunum.
Serosa
Inner-circular
Outer-longitudinal Muscularis
Sub-mucosa
Mucosa
Lumen
They are small spherical multicellular glands.
*
They open into crypts of lieberkuhn with the help of fine tubules.
*
These glands are found in the submucoa of duodenum.
*
They synthesize and secrete the non enzymatic alkaline secretion of intestinal juice.
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02
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*
Paneth Cells :-
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21
Brunners Gland :-
These cells are found in mucosal layer of cypts of Lieberkuhn of jejunum.
*
They are unicellular glands.
*
They synthesize and secrete Lysozyme and defensin.
*
The secretory substances of Brunners glands and crypts of Lieberkuhn are combindly called intestinal juice or
succus entericus.
Se
*
Peyer's patches :*
They are small lymph nodes which are found in the mucosa of small intestine (Jejunum and Ileum more in
number).
They are also called intestinal tonsils and provide immunity.
Nerve supply :Two types of Nerve plexus are found in muscle of alimentary canal.
Auerbach's Nerve plexus (myentric plexus) this nerve plexus is found between longitudinal muscles and
circular muscles, it control muscle contraction
Meissner's Nerve plexus found between circular muscles and sub mucosa but in stomach it is found between
oblique muscle & submucosa.
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BEGINNERS BOX-2
HISTOLOGY OF ALIMENTARY CANAL
Peyer's patches produce(1) Enterokinase
4.
(1) Estrogen
(2) Prolactin, parathormone
(3) Extradiol, progesterone
(4) None
Brunner's gland are found in which of the following layers :
(1) Submucosa of stomach
(2) Mucosa of ileum
(3) Submucosa of duodenum
(4) Mucosa of oesophagus
The crypts of lieberkuhn secret :
(1) gastrin
5.
(4) succus entricus
(2) Duodenum
(3) Intestine
(4) Stomach
(2) Stomach
(3) oesophagus
(4) All of these
Out of four layers of alimentary canal, which one forms villi, (finger-like projection)?
(1) Serosa
8.
(3) cholecystokinin
Crypts of Lieberkuhn are present in :(1) intestine
7.
(2) rennin
Brunner's glands are located in :
(1) Oesophagus
6.
(4) Trypsin
Duodenum has characteristic Brunner's glands which secrete –
21
3.
(3) Mucous
(2) Mucosa
(3) Submucosa
0-
2.
(2) Lymphocyte
(4) Muscularis
Small finger-like projection, which produce numerous microscopic projections are supplied with a network of
02
1.
(2) blood capillaries only
:2
(1) blood capillaries and lacteal
(3) lacteal only
(4) a large lymphoid vessel and valves
io
n
DIGESTIVE GLANDS-
ss
The digestive glands associated with the alimentary canal include the salivary glands, the liver and the pancreas.
Se
SALIVARY GLANDS- Saliva is mainly produced by three pairs of salivary glands, the parotids (cheek), the sub
maxillary/sub mandibular (lower jaw) and the sub linguals (below the tongue).
These glands are situated outside the buccal cavity, secrete salivary juice into the buccal cavity.
In human 3 pairs of salivary glands are present.
Parotid
Submaxillary
Sublingual
1.
Location
Below ear (cheek)
Jaw angle (lower jaw)
Below tongue
2.
Number
1 pair
1 pair
1 pair
3.
Duct
Stenson's duct
Wharton's duct
(longest salivary duct)
Duct of Rivinus or
Bartholin's duct
(smallest salivary
duct)
4.
Secretion
Saliva + Enzymes
Saliva
Saliva
5.
Special point
Largest salivary gland
and viral infection
cause Mumps.
Secrete maximum
amount of saliva
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Salivary Glands : 3 Pairs
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Composition of saliva :
Salivary glands are not present in whale and frog.
*
Water-99.5 %
*
Mucus , starch -digesting Ptyalin enzyme, lysozyme and thiocyanates and few ions like sodium, potasium,
chloride, IgA antibody, urea and uric acid etc., are present.
*
Ptyalin is secreted mainly by the parotid gland. Lysozyme and Thiocyanates mainly kill bacteria. They also check
the growth of bacteria in bucco-pharyngeal cavity.
*
Salivation is stimulated by cranial nerve VII & IX. Sympathetic nervous system decreases the secretion of saliva
while parasympathetic nervous system increases the secretion of saliva.
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LIVER
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*
It develops from endoderm. (Weight 1.2 to 1.5 kg). In human it is found in right side of abdominal cavity,
below the diaphragm.
*
The liver is the largest gland of body.
*
It is made up of two lobes, left and right lobe. Left lobe is smaller than right lobe. Right lobe forms 5/6 of the
liver & left lobe forms 1/6 of liver.
*
Right and left liver lobes are separate from each other by the falciform ligament, (Fibrous C.T.) which is
made up of fold of peritoneum.
*
Right and left hepatic duct develop from right and left liver lobe. Both these ducts combine to form a Common
Hepatic duct.
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The hepatic lobules are the structural and functional units of liver containing hepatic cells arranged in the form
of cords. Each lobule is covered by a thin connective tissue sheath called the Glisson’s capsule. The bile secreted
by the hepatic cells passes through the hepatic ducts and is stored and concentrated in a thin muscular sac called
the gall bladder. The duct of gall bladder (cystic duct) along with the hepatic duct from the liver forms the
common bile duct The bile duct and the pancreatic duct open together into the duodenum as the common
hepato-pancreatic duct which is guarded by a sphincter called the sphincter of Oddi.
*
Gall bladder is situated below right lobe of liver. Gall bladder is not present in lemprey, whale and horse.
*
Cystic duct of gall bladder is connected to common hepatic duct to form a common bile duct also called ductus
choledocus.
FUNCTIONS OF LIVER :- (Liver is known as biological and chemical factory of the body).
Most of the biochemical functions of the body are done by the liver.
1.
Secretion & synthesis of bile - This is the main function of liver. Bile is yellowish-green, alkaline fluid. In bile
juice, bile salts, sodium bicarbonate, glycocholate, taurocholate, bile pigments, cholesterol, Lecithin etc. are
present.
Bile salts help in emulsification of fats. Bile prevents the food from decomposition. It kills the harmful bacteria.
Carbohydrate Metabolism- The main centre of carbohydrate metabolism is liver.
Following steps are related with carbohydrate metabolism-
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2.
02
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Glycogenesis- The conversion and storage of extra amount of glucose into glycogen from the digested food is
:2
called glycogenesis. The main stored food in the liver is glycogen.
n
Glycogenolysis- The conversion of glycogen into glucose again when glucose level in blood falls down is called
ss
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glycogenolysis.
Se
Gluconeogenesis- At the time of need, liver converts non-carbohydrate compounds (e.g Amino acids, fatty
acids) into glucose. This conversion is called gluconeogenesis. This is the neo-formative process of glucose.
Glyconeogenesis : Synthesis of glycogen from lactic acid (which comes from muscles) is called glyconeogenesis. This
is the neo-formative process of glucose.
Storage of fats- Liver stores fats in a small amount. Hepatic cells play an important role in fat metabolism.
The storage of fat increases in the liver of alcohol addict persons (Fatty liver). This stored fat decreases the
activity of liver. The damage of liver due to alcohol intake is called Alcoholic Liver cirrhosis.
4.
Deamination and Urea formation- Deamination of amino acids is mainly done by liver (Amino acid ® NH3)
Liver converts ammonia (more toxic) into urea (less toxic) through ornithine cycle.
The spoilage of liver, the ammonia level in the animal body increases and ultemately the animal dies.
5.
Purification of blood- Kupffer cells of liver & splenocytes of spleen are the phagocytic cells, helps in phagocytosis of dead blood cells and bacteria from the blood.
6.
Synthesis of plasma proteins- Many types of proteins are present in blood plasma. All the proteins except
Gama-globulins are synthesized in the liver. Chemically antibodies are gama globulins formed by lymphocytes.
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Synthesis of heparin- Heparin is a natural anticoagulant (mucopolysaccharide).
Some heparin is also formed by basophills (granulated WBC) and mast cells.
8.
Synthesis of Vitamin-A- The liver changes b-carotene into vitamin -A b- carotene is a photosynthetic pigment which is obtain from yellow part of fruits. It is abundantly found in carrot.
9.
Liver stores vitamins A,D,E,K,B12
10.
Storage of minerals- Liver stores iron, copper, zinc, cobalt, molybdenum etc. Liver is a good source of iron.
11.
Haemopoiesis- The formation of blood cells is called haemopoesis. In embryonic stage R.B.C and WBC are
formed by liver
12.
Secretion of enzymes- Some enzymes are secreted by liver, participate in metabolism of proteins, fats and
carbohydrates e.g. Dehydrogenase, cytochrome oxidase etc.
13.
Prothrombin and fibrinogen proteins are also formed in hepatic cells. These help in blood clotting.
14.
Factors I, II, V, VII , IX and X are formed in liver, which are responsible for blood clotting.
Deficiency of selenium, causes liver necrosis.
BILE-JUICE
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In the middle part of the duodenum bile-juice is secreted. The parenchyma cells of the liver produce bile-juice
and it is stored in the Gall- bladder. Bile-juice does not contain any digestive enzyme. Therefore it is not a true
digestive juice (Pseudodigestive juice).
Compostion of Bile-juice :- Bile-juice is a greenish (Biliverdin) yellow (Bilirubin) coloured alkaline fluid.
:2
Composition of liver bile.
98%
io
H2O
ss
8.0
Se
pH
n
Liver bile
organic constituents are bile acid , bile pigment, cholesterol, Lecithin, inorganic constituents
Na+, K+ etc.
Bile-pigments are the excretory-substances of the liver.
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Bile-salts are of two types –
E
(a)
Inorganic- salts- Bile-juice contains NaCl, Na2CO3, NaHCO3 etc in it. Inorganic salts neutralize the
acidity of the food and make the medium basic. It is necessary for the medium to become basic because
the pancreatic-juices enzymes can act only in basic -medium.
(b)
Organic- salts- Organic salts like Na-glycocholate and Na-taurocolate are found in Bile juice. The main
function of these salts is the emulsification of fats. Because pancreatic Lipase can act only on emulsified
fats.
Bile salts also help in the absorption of fats and fat-soluble vitamins (A,D,E,K) Bile salts combine
with fats, cholestrol, phospholipid (lecithin) and these vitamins to form compounds called Micelles.
Which are absorbed rapidly. In the form of micelles cholestrol and phospholipid (lecithin) remain soluble.
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FUNCTION OF BILE JUICE :
*
*
*
*
*
*
*
*
*
*
Neutralization of HCl. Its sodium neutralizes HCl of chyme (semifluid food found in the stomach).
Emulsification. Sodium glycocholate and sodium taurocholate are bile salts which break the large fat
droplets into the smaller ones.
Absorption of fat and fat-soluble vitamins. Its salts help in the absorption of fat (fatty acids and glycerol)
and fat-soluble vitaminS (A, D, E and K).
Excretion. Bile pigments (billirubinand biliverdin) are excretory products.
Prevention of decomposition. Bile is alkaline hence it prevents the decomposition of food preventing the
growth of bacteria on it.
Stimulation of peristalsis. Bile increases peristalsis of the intestine.
Activation of Lipase. Bile contains no enzyme but activates the enzyme lipase.
Bile-pigments, cholesterol and Lecithin are the excretory substances found in Bile-juice.
Gall-Stone- Sometimes the passage inside the bile-duct gets blocked or becomes narrow, so the cholesterol
gets deposited or precipitated in the gall-bladder. This is termed as the Gall-stone (cholelithiasis).
Obstructive Jaundice - If the passage of bile is blocked then the amount of bilirubin increases in the blood. So
the yellowish colouration of body like skin, cornea and nails appear yellow. Urine also becomes yellow.
PANCREAS (Sweet bread)
It develop from endoderm, which is soft, lobulated and elongated organ.
*
It is divided into head, neck, body and tail regions.
*
It is made up of numerous acini. Acini is a group of secretory cells surrounding a cavity. Each acini is lined by
21
*
02
*
0-
pyramidal shaped cells. These acinar cells secrete the enzyme of pancreatic juice.
Each acini opens into pancreatic ductule. Many pancreatic ductule combine to form main Pancreatic duct
:2
(duct of Wirsung). The main Pancreatic duct is join with the bile duct to form the hepatopancreatic ampulla
n
which opens into duodenum. The accessory Pancreatic duct (duct of Santorini) opens into duodenum with
Some group of endocrine cells are also found in between groups of acini called islets of Langerhan's. These
Se
*
ss
io
separate openings located above the opening of major Pancreatic duct.
islets secrete insulin & glucagon hormone. So this gland is exocrine as well as endocrine (Heterocrine). Its
99% part is exocrine while 1% part is endocrine.
*
In humans both bile duct and pancreatic duct combine to form common duct called as Hepato-Pancreatic
ampulla. Ampulla of Vater opens into middle part of Duodenum and is controlled by sphincter of Oddi while
bile duct is controlled by sphincter of Boyden
PANCREATIC JUICE
*
Pancreozymin stimulates the acini and glandular cells so pancreatic juice is secreted.
*
The pancreatic-juice is secreted by the exocrine cells of the pancreas.
*
Pancreatic juice is highly odouriferous, colourless basic fluid which contains enzymes and salts.
Composition of Pancreatic JuiceTotal amount in man = 1 litre to 1.5 litre/day,
Water = 98%,
pH = 7.5-8.3,
Pancreatic juice contains only inorganic-salts.
Salts = 2%
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duct. The terminal end of common duct is swollen and is called as Ampulla of Vater or hepato pancreatic
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BEGINNERS BOX-3
DIGESTIVE GLANDS
(3) Specialized area, pituitary
(4) Small tubules, kidney
Ptyalin is secreted by __________ and work in __________ medium.
(1) Stomach, acidic
(2) Salivary gland, alkaline
(3) Pancreas, alkaline
(4) Bile, alkaline
In pancreas, pancreatic juice and hormone are secreted by(1) Same cells
(2) Different Cells
(3) Same cells at different times
(4) None of these.
Largest gland of body -
5.
(3) Liver
Insulin is secreted by pancreatic cells(1) a-cells
6.
(2) Duodenum
(4) Thyroid
21
(1) Pancreas
0-
4.
(2) Ductless glands, pancreas
(2) b-cells
(3) Delta cells
(4) Gama cells
02
3.
(1) Modified lymph glands, pancreas
Which substance of saliva destroy the harmful bacteria(2) Chyme
(3) Lysozyme
(4) Secretin
Which of the following is not a function of liver :-
Se
7.
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(1) Cerumin
:2
2.
Islets of langerhans __________ and are found in __________.
n
1.
(1) Deamination
(3) Synthesis of plasma protein
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8.
E
9.
(4) Storage of fat soluble vitamin
The glucose is converted into glycogen in liver and stored in :
(1) Liver
(2) Liver and muscles
(3) Liver and spleen
(4) Spleen and muscles
Kupffer cells are found in :
(1) Liver
10.
(2) Bile storage
(2) Kidney
(3) Heart
The major site of protein breakdown to form free amino acids, is in the
(1) Kidney
(2) Spleen
(3) Intestine
(4) Bone-marrow
(4) Blood
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PHYSIOLOGY OF DIGESTION
Digestion is divided in two ways-Mechanical digestion and Chemical digestion. Mechanical digestion takes place
in mouth and small intestine.
DIGESTION IN ORAL CAVITY
Food enters through mouth food is tasted in oral cavity and mixed with saliva, tongue mixes the food with saliva.
This food with saliva is called bolus. This saliva (pH 6.8 – 7.0) contains water (99.5%) and electrolytes (Na+, K+,
Cl–, HCO3–, Thiocynate).
Mechanical digestion :–
*
In mouth teeth, tongue and lips have important role in machanical digestion through the process of
chewing or mastication.
Chemical digestion :*
In this type of digestion saliva mix with food particles.
*
Saliva contain 99.5% water & 0.5% salts.
*
These salts are organic and inorganic type.
Mucin :*
It is a glycoprotein. It lubricates the food particles. It helps in the swallowing of food.
Ptyalin
Starch ¾¾¾¾® Maltose
02
*
0-
21
*
Bicarbonates present in saliva neutralize the acidity of food.
Lysozyme :*
It is an enzyme which kills the harmful bacteria. Due to this reason saliva is a antiseptic lotion.
Thiocynate :*
It is a special salt which kills the harmful bacteria. So it is called bacteriocidal salt.
Ptyalin (Salivary amylase) :-
:2
Ptyalin is found in human saliva, because human food is mainly made up of starch. Ptyalin digest only ripe
n
and cooked starch. It does not digest the raw starch, 30% starch in buccal cavity is digested by ptyalin.
io
Ptyalin is absent in saliva of rabbit and carnivorous animal, because food of rabbit is mainly made up
ss
of cellulose whereas carnivore food mainly contain proteins.
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20
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21
Bolus is pushed inward through the pharynx into the oesophagus this process is called swallowing or deglutition.
It is coordinated activity of tongue, soft palate, pharynx and oesophagus.
*
The tongue blocks the mouth, part of soft palate and uvula close off the internal nasal opening nose and larynx
rises so that epiglottis closes off the trachea food move downward into the oesophagus A travelling wave of
constrictions called peristalsis pushes the Bolus (food) downward.
*
Digestive enzymes are absent in Oesophagus but salivary amylase continue to function upto the last of Oesophagus.
The cardiac sphincter/ Gastroesophageal sphincter opens allowing the passage of bolus food to the stomach.
Gastroesophageal sphincter normaly remains closed and does not allow food contents of the stomach to move
n
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21
back.
Se
DIGESTION IN STOMACH
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io
PERISTALSIS IN OESOPHAGUS
The stomach stores the food for 4-5 hours. The food mixes thoroughly with the acidic gastric juice of the
stomach by the churning movements of its muscular wall and is called the chyme. The proenzyme pepsinogen,
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on exposure to hydrochloric acid gets converted into the active enzyme pepsin, the proteolytic enzyme of the
stomach. Pepsin converts proteins into proteoses and peptones (peptides). The mucus and bicarbonates present
E
in the gastric juice play an important role in lubrication and protection of the mucosal epithelium from excoriation by the highly concentrated hydrochloric acid.
Food reaches in stomach and then G-cells secrete gastrin hormone, which stimulates secretion of gastric juice.
Gastric juice secretion is controlled by neural hormonal method and by chemical substances.
Composition of Gastric juice :
Secretion = 2000 ml to 3000 ml per day
Water = 99.5%
HCl = 0.2 - 0.3%
pH = 1.5 to 2.5 (very acidic)
rest = mucus water, HCl and gastric enzymes (Pepsinogen, Prorennin, Gastric Lipase etc.).
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Functions of HCl –
1.
The main function of HCl (activater) is to convert inactive enzymes (zymogens) into active enzymes.
Pepsinogen ¾ ¾® Pepsin.
HCl
Prorennin ¾ ¾® Rennin.
HCl
2.
It destroys all the bacteria present in the food.
3.
HCl stops the action of saliva on food. In stomach, the medium is highly acidic.
4.
It dissolves the hard portions of the food and makes it soft.
*
Pepsinogen and Prorennin are inactive enzymes.
Digestion by Rennin (Chymosin) -
*
Rennin is active in the childhood stage of mammals only. It converts milk into curd like substance (clot the milk)
and then digests it. In adult stages, it is inactive.
*
Rennin, acts on milk protein casein. Casein is a soluble protein.
*
In presence of Rennin, casein gets converted into insoluble Ca-paracaseinate. This process is termed as
Curdling of milk. After becoming insoluble, milk can remain in the stomach for a longer time. (clotting/
0-
21
coagulation/curdling of milk is done by HCl, pepsin and chymotrypsin in human) .
02
Digestion by Pepsin-
:2
Inactive pepsinogen on getting proper pH converts into active pepsin. Pepsin is endopeptidase, which break
n
proteins into small molecules.
ss
Digestion by Gastric Lipase-
Se
Pep sin
io
Proteins ¾ ¾¾® Peptones + Proteoses + Peptides.
*
It converts fats into fatty-acids and glycerols. It is secreted in a less amount so less digestion of fats takes place here.
*
This lipase acts on emulsified fat and convert it into fatty acid & glycerol. 1% emulsified fat is present in the food.
*
Peristalsis continues during the process of digestion so the gastric -juice mixes properly with the food. Due to
stomach is called chyme.
*
After short intervals, the pyloric orifice keeps on opening and closing so the chyme is fed into the intestine in
installments.
DIGESTION OF FOOD IN SMALL INTESTINE*
In small intestine mechanical and chemical digestion occurs.
Mechanical Digestion : Food reaches to different parts of alimentary canal by peristalsis.
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peristalsis the food is converted into a paste. This form of food which is thick, acidic & semidigested in the
E
2
l
l
3
7
4
N
Se
Duocrinin - Stimulate Brunners glands for syn/sec
of non-enzymatic part of intestinal juice
Enterocrinin - Stimulate crypts of lieberkuhn or
syn/sec of enzymatic part of intestinal juice
Villikinin - Increase the activity of villi
ENTEROENDOCRINE CELLS OF INTESTINE
decomposition
Prevent food from
Activate pancreatic lipase
Helps in emulsification of
fats.
l
ININ
ATOCR
HEP
ETION OF BILE J
UIC E
S ECR
IS &
l
Also called pseudodigestive juice
Inhibit the action of HCl
l
BILE JUICE - pH 8.0 ; alkaline in nature
ES
TH
N
SY
ss
8
OF
n
AC
IN
I
io
PA
NC
02
1
0-
5
21
HCl in Chyme
l
AT
YM
Increase peristalsis in intestine
Decrease peristalsis in stomach
Proteins
Peptones
Proteoses
STIM
SO
ULATED CELL
F
Nucleosides
Nucleotides
Sucrose
Lactose
Maltose
Dipeptides
11
Nucleotides
Nucleosidases
Nucleotidases
Sucrase
Lactase
Maltase
Dipeptidases
Nitrogen bases + Pentose Sugar
Nucleosides + Phosphate Group
Glucose + Fructose
Glucose + Galactose
Glucose + Glucose
Amino acids
12
Nucleosides
Monoglycerides
Disaccharides
Dipeptides
DIGESTION IN JEJUNUM AND ILEUM
Biomicromolecules are digested in presence
of intestinal juice
Nucleic acids
Diglycerides
Nucleases
Pancreatic Lipase
Pancreatic amylase
Trypsin/Chymotrypsin
Carboxypeptidase
Polysaccharides (starch)
Fats
10
DIGESTION IN DUODENUM
Biomacromolecules are digested in presence
of bile juice and pancreatic juice
l
l
VIP - Vasoactive Intestinal Peptide
Decrease the secretion of gastric juice in stomach
9
GIP - Gastric Inhibitory Peptide (Glucose dependent
insulinotrophic peptide)
Stimulate pancreas for
syn/sec of non-enzymatic
part of pancreatic juice
Inhibit the secretion of HCl in
stomch so also called fireman
of small intestine
NZ
CCK-PZ
FE
RE AS FO SYN/SEC O
R
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6
l
l
PHYSIOLOGY OF DIGESTION
P
A
RT
OF
PANC
REATIC JUICE
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C
PZ
OR SEC
ER F
KRE
C ADD ICE
TI
O
JU
L
B LE
I
STIMULATE
G
AL
OF L
B
E
IC
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Pre-Medical : Biology
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DIGESTION IN DUODENUM :
Pancreatic, a - Amylase : Amylase and Amylopsin dissociates starch into Maltose. Majority of starch breaks
up into the duodenum.
Pancreatic amylase
® Maltose
Starch ¾¾¾¾¾¾¾
(Amylopsin)
Protein digestion in duodenum Dipeptides and Amino acids
Procarboxypeptidase
Carboxypeptidase
Duodenal mucosa
Pancreatic juice
Trypsinogen
Trypsin
Entrokinase + Ca+2
Large peptides
Chymotrypsinogen
Chymotrypsin
Proteins
Fat digesting enzyme - In pancreatic-juices various Fat-digesting enzymes are found which are collectively
called steapsin.
(I)
Pancreatic Lipase- It converts triglyceride into monoglyceride,fatty acid, glycerol.
(II) Cholesterol esterase- It digests cholesterol esters. These esters are made up of cholesterol and
fatty-acids Like- Lanolin, (cholesterol and Palmitic acid).
(III) Phospholipase- These digest phospholipids.
DNase and RNase - Digestion of DNA and RNA.
In duodenum, digestion of biomacro molecules takes place in the presence of bile juice and pancreatic juice.
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0-
21
DIGESTION IN JEJUNUM AND ILEUM Some hormones like duocrinin, enterokinin stimulate the crypts of Leiberkuhn to secrete Succus-entericus or
intestinal juice. This succus entericus mainly contains water (99%) and digestive enzymes (<1%).
Succus-entericus mainly contains the following enzymesPeptidase or Erepsin - This is a type of Exopeptidase. It converts oligopeptides into amino-acids.
Disaccharidases
*
Sucrose
*
Maltose
Maltase
Glucose + Glucose
*
Lactose
Lactase
Glucose + Galactose
ss
io
n
Glucose + Fructose
Se
Sucrase (Invertase)
Intestinal Lipase- This fat-digesting enzyme converts fats into fatty-acids and glycerol.
Fat
Lipase
Fatty acid + Glycerol
Nucleotidase
® Nucleosides + Phosphate
(i) Nucleotides ¾¾¾¾¾¾¾
Nucleosidase
® Pentose + Nitrogen base
(ii) Nucleosides ¾¾¾¾¾¾¾
*
*
DIGESTION IN CAECUM :In herbivores, the symbiotic bacteria and protozoans present in the caecum help in digestion of cellulose into
glucose. So the digestion of cellulose takes place in caecum by the process of decomposition. This decomposition process is very slow. So very less amount of cellulose is digested at a time in caecum.
In the last part of the large intestine faeces is temporarily stored.
Maximum digestion of food – Duodenum.
While digestion of food complete in – Ileum.
Maximum absorption of food in – Jejunum.
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Nucleotidase and Nucleosidase - These act in the following way:-
E
Bile
juice
ss
SALIVARY
GLAND
io
n
STOMACH
OESOPHAGUS
(1) STARCH
pH = 6.8
Contain ptyalin (Salivary amylase)
MALTOSE
Se
:2
02
0-
21
Gastric
(2)
amylase
Gastric Lipase convert 1% emulsified
(inactive)
fats into fatty acids and Glycerol
HCL inactivate
(3)
Pepsin
Proteins
Proteoses +
Fo od
ptyalin
GALL-BLADDER
+
Peptones
G
J
u
a
ice =
st
HCL convert inactive
S
CHYric
Concentration
PANCREAS
proteases into
ME
and storage of
active one
M
DNase, RNase
bile juice
Dipeptides and
Pancreatic amylase, Pancreatic
Bile juice emulsify
amino acid
Lipase, Trypsinogen,
A
fats
CARBOXY
Chymotripsinogen,
(4)
Pancreatic lipase
PEPTIDASE
procarboxy peptidase
Tryglyceride
L (6)
PROCARBOXY
DNA by DNase
Monoglycerides
(7)
PEPTIDASE
LARGE
RNA by RNase
+
T
E
TRYPSINOGEN
PEPTIDES
Fatty acids + Glycerol
N
enterokinase
L
TRYPSIN
I
(8)
S
Pancreatic
I
Maltose
(5) STARCH
CHYMO
Amylase
N
T
TRYPSINOGEN
T
CHYMO
E
I
4,5,6,7,8 in duodenum
PROTEINS
TRYPSIN
S
T
I
N
maltase
(9) Maltose
Glucose + Glucose
N
A L
9 to 15 in jejunum and ileum
A
E
lactase
R
L
(10) Lactose
Glucose + Galactose
G
J
Sucrase
U
(11) Sucrose
Glucose + Fructose
E C I
E
dipeptidase
I
(12) Dipeptides
Amino acids
N
intestinal lipase
T
(13) Monoglycerides
Fatty acids + Glycerol
ES
nucleotidases
(14) Nucleotides
Nucleosides + PO3–
4
T I
NE
nucleosidases
(15) Nucleosides
N2 bases + Pentose sugar
Liver
Physiology of digestion
PROTEINS
FATS
STARCH
SALIVA
pH
=1
.5
E
–3
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ALLEN
Pre-Medical : Biology
ted
es
g
i
d i al
Un ater
m
25
26
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Pre-Medical : Biology
BEGINNERS BOX-4
PHYSIOLOGY OF DIGESTION
1.
Bilirubin and bilivirdin are found in(1) Blood
2.
(2) sugar
(3) protein
(4) fat
(2) Protein
(3) Fat
(4) Cane sugar
The digestion of cellulose in rabbit and other herbivorous mammals takes place in(1) Vermiform appendix
5.
(4) None of these.
Amylase enzyme acts on the (1) Starch
4.
(3) Saliva
Casien present in milk,which is (1) bacterium
3.
(2) Bile
(2) Colon
(3) Caecum
(4) Ileum
Peristaltic movements found in different parts of alimentary canal In which one of these there is least
peristalsis(1) Stomach
(4) lactose
(2) Sucrose into glucose and fructose
(3) Starch into maltose
(4) Starch into sucrose
Trypsin is secreted by(3) Liver
0-
(2) Stomach
21
(1) Glucose into sucrose
Proteins are broken down into amino acids in(1) Buccal cavity
10.
(3) Trypsin
The enzyme invertase hydrolase-
(1) Pancreas
9.
(2) Rennin
02
8.
(4) Oesophagus
Milk protein is curdled into calcium paracaesinate by(1) Maltose
7.
(3) rectum
(2) Stomach
(3) Intestine
:2
6.
(2) duodenum
(4) Ileum
(4) Rectum
Digestion of starch starts from the mouth, whearas ...A... is the site of digestion mainly for ...B... Choose the
io
n
correct combination of options to complete the given statement.
Se
(3) A-small intestine; B-protein
ss
(1) A-stomach; B-protein
(2) A-stomach; B-starch
(4) A-small intestine; B-starch
BEGINNERS BOX-5
PHYSIOLOGY OF DIGESTION
1.
Herbivorous animals can digest cellulose because
(2) Bacteria present in their caecum help in digestion of cellulose.
(3) Gastric juice has a digestive enzyme for cellulose digestion.
(4) Alimentary canal is very long.
2.
Digestion of carbohydrate is affected by(1) Amylopsin
3.
4.
(2) Lipase
(3) Erepsin
(4) Pepsin
Ptyalin cannot work in stomach, because it becomes(1) Inactive due to HCl
(2) Inactive due to Renin
(3) Inactive due to Pepsin
(4) None of these
What is the important function of bile(1) For digestion by emulsification of fats
(2) Elimination of excretory products
(3) For digestion by enzymes
(4) Coordination of digestive activities
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(1) Their molar and premolar teeth can crush and grind the food.
E
ALLEN
5.
6.
7.
8.
9.
10.
Pre-Medical : Biology
27
Some proteolytic enzymes are(1) Trypsin, Erepsin, Pepsin
(2) Amylase, Lipase, Zymase
(3) Ampylopsin, Steapsin, Ptyalin
(4) Urease, Dehydrogenase, Zymase
Bacteria entering with contaminated food are killed in stomach by (1) Pepsin
(2) Renin
(3) Sodium bicarbonate (4) HCl
Chymotrypsin is(1) Proteolytic enzyme
(2) Fat digestive enzyme (3) Vitamin
(4) Hormone
Emulsification of fats by bile takes place in(1) Duodenum
(2) Liver
(3) Stomach
(4) Intestine
Which of the following secretions gets mixed with the food (hydrolysed) in the small instestine?
(1) Bile, pancreatic juices and intestinal juices
(2) Pancreatic juices, intestinal juices and gastric juices.
(3) Gastric juices, intestinal juices and biles
(4) Bile, gastric juices and salivary juices
What is the major site for the conversion of proteins into free amino acids?
(1) Spleen
(3) Intestine
(2) Liver
(4) Kidney
DIGESTIVE JUICES
Saliva
Composition
Functions
Water (99.5%), Solids (0.5%)
Keeps the mouth moist.
Inorganic and organic salts,
Helps in formation of bolus.
02
Splits starch into maltose.
Protein digestion up to
peptone and proteoses
Inorganic and organic salts, mucin,
Enzymes : pepsinogen, rennin,
lipase etc
Milk degestion
:2
Water (99.5%), Solids (0.5%)
HCl (0.2 – 0.3%)
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E
ss
io
n
Gastric
Juice
0-
- Ptyalin, mucin
21
Name of the juice
Inorganic and organic constituents,
Enzymes : trypsinogen,
Chymotrypsinogen, Procarboxy
peptidase, nucleases, lipase
Digestion of carbohydrates,
proteins and fats
Bile Juice
Inorganic salts, bile salts, bile
pigments (Bilirubin, Biliverdin),
Cholesterol
Helpuful in digestion of lipid
Water 99% and Solid 1%
Activator : Enterokinase
Enzymes : Erepsin, nucleotidases,
sucrase, maltase, lactase, lipase.
Digestion of all type of food.
Intestinal
juice
Se
Pancreatic
juice
Removes the acidity.
REGULATION OF DIGESTION
The activities of the gastro-intestinal tract are under neural and hormonal control for proper coordination of
different parts. The sight, smell and/or the presence of food in the oral cavity can stimulate the secretion of
saliva. Gastric and intestinal secretions are also, similarly, stimulated by neural signals. The muscular activities
of different parts of the alimentary canal can also be moderated by neural mechanisms, both local and through
CNS. Hormonal control of the secretion of digestive juices is carried out by the local hormones produced by the
gastric and intestinal mucosa.
28
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Pre-Medical : Biology
ABSORPTION OF DIGESTED FOOD
Absorption is the process by which the end products of digestion pass through the intestinal mucosa into the
blood or lymph. It is carried out by passive, active or facilitated transport mechanisms. Small amounts of
monosacharides like glucose, amino acids and some of electrolytes like chloride ions are generally absorbed by
simple diffusion. The passage of these substances into the blood depends upon the concentration gradients.
However, some substances like glucose and amino acids are absorbed with the help of the carrier proteins. This
mechanism is called the facilitated transport.
Transport of water depends upon the osmotic gradient. Active transport occurs against the concentration gradient and hence requires energy. Various nutrients like amino acids, monosacharides like glucose, electrolytes like
Na+ are absorbed into the blood by this mechanism. Fatty acids and glycerol being insoluble, cannot be absorbed into the blood. They are first incorporated into small droplets called micelles which move into the
intestinal mucosa. They are re-formed into very small protein coated fat globules called the chylomicrons which
are transported into the lymph vessels (lacteals) in the villi. These lymph vessels ultimately release the absorbed
substances into the blood stream. Absorption of substances takes place in different parts of the alimentary
canal, like mouth, stomach, small intestine and large intestine. However, maximum absorption occurs in the
small intestine. A summary of absorption (sites of absorption and substances absorbed) is given in table.
The Summary of Absorption in Different Parts of Digestive System
Small Intestine
Principal
organ
for
absorption of nutrients.
The digestion is completed
here and the final products
of digestion such as
glucose, fructose, fatty
acids, glycerol and amino
acids are absorbed through
the mucosa into the blood
stream and lymph.
Large Intestine
Absorption
of
water,
some
minerals
and
drugs takes place.
n
:2
02
0-
21
Stomach
Absorption
of
water,
simple
sugars,
and
alcohol etc. takes
place.
Se
ss
io
Mouth
drugs
Certain
coming in contact
with the mucosa
of mouth and
lower side of the
tongue
are
absorbed into the
blood capillaries
lining them.
ABSORPTION IN DUODENUM : In duodenum iron and calcium ions are absorbed.
ABSORPTION IN JEJUNUM : Maximum absorption of food takes place in jejunum.
(Fats does not follow entero hepatic circulation)
Glucose
Glucose + Na+
L–amino acids
D-amino acids
Fats are absorbed
into lacteals in the
form of chylomicrons
L
Folds of mucosa
Blood capillaries
A
C
T
Liver
Hepatic portal
vein
Hepatic Vein
Mesenteric
Vein
Inferior Vena
Cava
Superior Vena
Cava
E
A
L
Lymph
Vessels
Left Thoracic
Lymph duct
Left Subclavian Vein
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Enterocyte
Mucous cell
Microvilli
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Pre-Medical : Biology
29
Caloric value :
*
The amount of heat liberated from complete combustion of 1 gm food in a bomb calorimeter (a closed metal
chamber filled with O2) is its gross calorific value or gross energy value (G.C.V.).
*
The actual amount of energy liberated in the human body due to combustion of 1 gm of food is the physiologic
value (P.V.) of food.
Food substance
G.C.V.
P.V.
(in K.cal/gm)
(in K.cal/gm)
Carbohydrate
4.1
4.0
Protein
5.65
4.0
Fats
9.45
9.0
ASSIMILATION OF FOOD :
•
Glucose ¾® Glycogen in liver (Glycogenesis) (Glycogen is stored food material)
•
Whenever required, Glycogen ¾® Glucose (Glycogenolysis)
•
Amino acids and fats ¾® Glucose in liver (Gluco neogenesis)
•
Lactic acid formed in muscles ¾® Glycogen in liver by Glyconeogenesis
•
Stored in body, help in insulation and thermoregulation.
•
Rich source of energy
02
0-
21
Glucose is instant source of energy.
Minerals, water and vitamins plays vital role in many vital processes of body.
ss
(4)
Fats -
•
:2
(3)
Carbohydrates
n
(2)
io
(1)
The absorbed substances finally reach the tissues which utilise them for their activities. This process is called
assimilation.
Proteins and amino acids - Amino acids are not stored in body as they are highly reactive so converted into
proteins which are building blocks of body.
Se
EGESTION :
The digestive wastes, solidified into coherent faeces in the rectum initiate a neural reflex causing an urge or
desire for its removal. The egestion of faeces to the outside through the anal opening (defaecation) is a voluntary process and is carried out by a mass peristaltic movement.
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Faecal matter is yellowish brown in color due to the presence of two pigments (Stercobilin, Urobilin). These two
are formed due to degradation of bile pigments. Foul smell in excreta is due to the presence of CH4, NH3,
E
indole, scatole, tryphtophan and H2S.
BEGINNERS BOX-6
1.
2.
ABSORPTION OF DIGESTED FOOD
Amino acids are absorbed in(1) Blood capillaries of villi
(2) Wall of rectum
(3) lacteals and blood capillaries of villi
(4) lacteals of villi
Absorption of digested food chiefly occurs in(1) Stomach
(3) Small Intestine
(2) Colon
(4) Large Intestine
Excess amino acids are deaminated & converted into urea in (1) Kidneys
(3) Lactelas in jejunum
(4) Blood capillaries in deodenum
(2) absorption
(3) assimilation
(4) egestion
Process of absorption of nutrients in carried out by
(1) passive transport
(2) facilitated transport
(3) active transport
(4) all of the above
By which process, glucose and amino acids are absorbed in the small intestine?
(2) Passive transport
(3) Osmosis
(4) Selective absorption
21
(1) Active transport
What is the main site of amino acids absorption in human's small intestine?
(1) Duodenum
(2) Jejunum
(3) Ileum
Absorption of fat occurs through the process of
(2) passive transport
(3) osmosis
(4) simple diffusion
io
(1) active transport
(4) Both (1) and (2)
ss
DISORDERS OF DIGESTIVE SYSTEM
PEM
Dietary deficiencies of proteins and total food calories are widespread in many underdeveloped countries of
South and South-east Asia, South America, and West and Central Africa. Protein-energy malnutrition (PEM)
may affect large sections of the population during drought, famine and political turmoil. This happened in
Bangladesh during the liberation war and in Ethiopia during the severe drought in mid-eighties. PEM affects
infants and children to produce Marasmus and Kwashiorkar.
Marasmus is produced by a simultaneous deficiency of proteins and calories. It is found in infants less than a year
in age, if mother’s milk is replaced too early by other foods which are poor in both proteins and caloric value.
This often happens if the mother has second pregnancy or childbirth when the older infant is still too young. In
Marasmus, protein deficiency impairs growth and replacement of tissue proteins; extreme emaciation of the
body and thinning of limbs results, the skin becomes dry, thin and wrinkled. Growth rate and body weight decline
considerably. Even growth and development of brain and mental faculties are impaired.
Kwashiorkar is produced by protein deficiency unaccompanied by calorie deficiency. It results from the replacement of mother’s milk by a high calorielow protein diet in a child more than one year in age. Like marasmus,
kwashiorkor shows wasting of muscles, thinning of limbs, failure of growth and brain development. But unlike
marasmus, some fat is still left under the skin; moreover, extensive oedema and swelling of body parts are seen.
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\02-DIGEST-E.P65
10.
(2) Lacteals in colon
0-
9.
(4) Maltose
02
8.
(3) Galactose
Removal of waste from body in the form of undigested food in called
(1) digestion
7.
(2) Fructose
Fats are absorbed in ________
(1) Lacteals in stomach
6.
(4) Pancreas
__________ is the instant source of energy.
(1) Glucose
5.
(3) Spleen
:2
4.
(2) liver
n
3.
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Pre-Medical : Biology
Se
30
E
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Pre-Medical : Biology
31
Old man's face
Wasted muscles
Wasted mucles
Fat present
Very little fat
Underweight
Very underweight
Oedema
No Oedema
Two types of inadequate nutrition. (a) Kwashiorkor (b) Marasmus
Kwashiorkar
Marasmus
Occur in child more than one year of age
Occur in child below one year
2.
Deficiency of proteins only
Deficiency of protein and calories both
3.
Extensive oedema
No oedema
4.
Subcutaneous fat is still present
Subcutaneous fat disappear
5.
Wasting of muscles and thining of limbs
occur
Extreme emaciation of body and
thining of limbs occur
6.
Skin appear to be swollen
7.
Underweight children
02
0-
21
1.
:2
Skin is dry and wrinkled
io
n
Severely emaciated
1.
Se
ss
In both kwashiokar and marasmus physical growth and mental development is effected.
Hypercholesterolemia (Overnutrition) – It is caused due to intake of excess of saturated fat such as butter,
ghee, red meat, egg. Cholesterol level in blood rises abnormally (hypercholesterolemia) this may cause thrombosis and heart attack.
2.
Obesity (Overnutrition) – It is caused by excessive intake of high caloric nutrients such as sugar, honey and
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saturated fat. Fat accumulates in the tissue. This may cause high blood pressure, diabetes and heart diseases.
E
Regular exercise and taking of green leafy vegetable are recommended to such persons.
3.
Hypervitaminosis (Overnutrition) – It is caused by excessive intake of vitamin. Such as excess of vitamin D
causes deposition of calcium in soft tissue. Excess of vitamin A causes lack of appetite, itching rash etc.
Hypervitaminosis of 'D'-Nausea, anorexia, hypercalcaemia, hyperphosphetemia, calcification of soft tissue.
4.
Fluorosis – It is caused by excessive intake of fluorine. It is characterised by mottled (brownish discolouration)
teeth.
5.
The inflammation of the intestinal tract is the most common ailment due to bacterial or viral infections. The
infections are also caused by the parasites of the intestine like tape worm, round worm, thread worm, hook
worm, pin worm, etc.
32
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Pre-Medical : Biology
6.
Jaundice: The liver is affected, skin and eyes turn yellow due to the deposit of bile pigments.
7.
Vomiting: It is the ejection of stomach contents through the mouth. This reflex action is controlled by the vomit
centre in the medulla. A feeling of nausea precedes vomiting.
8.
Diarrhoea: The abnormal frequency of bowel movement and increased liquidity of the faecal discharge is
known as diarrhoea. It reduces the absorption of food.
9.
Constipation: In constipation, the faeces are retained within the rectum as the bowel movements occur
irregularly.
10.
Indigestion: In this condition, the food is not properly digested leading to a feeling of fullness. The causes of
indigestion are inadequate enzyme secretion, anxiety, food poisoning, over eating, and spicy food
BEGINNERS BOX-7
DISORDERS
Kwashiorkar disease is due to deficiency of :
(1) protein
Continued consumption of a diet rich in butter, red meat and eggs for a long period may lead to :
(2) kidney stones
(3) hypercholesterolmia
(4) urine laden with ketone bodies
21
(1) vitamin A toxicity
0-
Marasmus disease is caused due to :
(1) Protein deficiency
(2) Obesity
(3) Dwarfism
(4) Deficiency of vitamins
Food is one of the basic requirment of all living organisms. The major component of our food are carbohydrates,
proteins and fats. Food provides energy and organic materials for growth and repair of tissues. Deficiency of
food will lead to protein energy malnutrition (PEM).
Se
ss
io
4.
(4) hormone
02
3.
(3) sugar
n
2.
(2) fat
:2
1.
Which one of the following disease is characterized by PEM ?
6.
(b) Kwashiorkar with wasted muscles
(c) Marasmus with old man's face
(d) Marasmus with oedema.
(1) a, b
(3) c, d
(4) a, b, c
Balanced diet is diet rich in carbohydrates, mild in protein and low in fats with essential vitamins and minerals.
Deficiency of proteins in diet of a children between age group of 1 to 3 will not lead of following symptoms.
(1) Wasted muscles
(2) Oedema
(3) Dwarfism
(4) Prominent ribs
Hypernutrition of which one of the following will read to itching rashes :
(1) Proteins
7.
(2) b, c
(2) Vitamin-D
(3) Fats
(4) Vitamin -A
Brownish discolouration of teeth is due to :
(1) Hypointake of flourine
(2) Hyperintake of vitamin-C
(3) Hyperintake of flourine
(4) Hypointake of vitamin-C
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5.
(a) Marasmus with changes in hair
E
ALLEN
Match the Column I & Column II correctly :
Column I
9.
A Marasmus
(i)
Itiching rashes
B Kwashiorkar
(ii)
Increase chance of
thrombosis
C Hypercholes
terolmia
(iii)
Old man's face
D Hypervitaminosis-A
(iv)
Oedema
(1) A - (iii), B - (ii), C - (iii), D - (iv)
(2) A - (iii), B - (iv), C - (ii), D - (i)
(3) A - (iii), B - (iv), C - (i), D - (ii)
(4) A - (i), B - (iv), C - (iii), D - (ii)
The abnormal frequent movement of the bowl and increased liquidity of the faeces is called
(1) vomiting
10.
Column II
(2) indigestion
(3) constipation
(4) diarrhoea
The inflammation of intestinal tract is due to the infection of which microganism?
(3) fungus
(2) virus
(4) both (1) and (2)
0-
(1) bacteria
21
8.
Pre-Medical : Biology
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E
B1
Thiamine
B2
Riboflavin vitamin-G or
Yellow Enzyme
Cyano - Cobalamine
B12
C
D
E
K
:2
n
io
Se
Vitamin Common name
A
Retinol
(2) Water soluble vitamin : B-complex and 'C'
ss
Earliest extracted vitamin = Vitamin - B1
Vitamins are following types –
(1)
Fat soluble vitamin : A, D, E, K
02
VITAMINS
Ascorbic Acid
Calciferol
Tocopherol/Antisterility/
Beauty Vitamin
Menadione/Phylloquinone
Deficeincy disease
Nightblindness
(Nyctalopia)
Xeropthalmia
Dermatitis
Beri-beri/Polyneuritis
/Cardio vascular
atrophy
Cheilosis, Glossitis, Keratitis
Pernicious anaemia (Megaloblastic anaemia)
Scurvy, Anaemia, Joint pain
Rickets in Children and Osteomalacia in
Adults
Macrocytic Anaemia, Muscular dystrophy
Severe bleeding
33
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Pre-Medical : Biology
An overview of the action of major digestive enzymes
Enzyme
Site of Action
Substrate
Products of Action
Salivary Juice (Salivary Gland)
Salivary amylase or Ptyalin
Buccal cavity
Starch
Disaccharides (few)
Proteins
Large peptides
Gastric Juice (Stomach)
Pepsin
Stomach
Pancreatic Juice (Pancreas)
Pancreatic a-amylase
Small intestine
Starch
Disaccharides
Trypsin
Small intestine
Proteins
Large peptides
Chymotrypsin
Small intestine
Proteins
Large peptides
Carboxypeptidases
Small intestine
Large peptides
Amino-acid
Lipase
Small intestine
Triglycerides
Monoglycerides
fatty acids,
Nucleases
Small intestine
Nucleic acids
Nucleotides
Intestinal Juice (Small Intestine)
Small intestine
Peptidase
Small intestine
Disaccharidases
Small intestine
Nucleotidase
Small intestine
Nucleosidases
Lipase
Trypsin
Amino-acid
Oligopeptides
Amino acids
Disaccharides
Monosaccharides
Nucleotides
Nucleosides
phosphoric acid
Small intestine
Nucleosides
Sugars, purines
pyrimidines
Small intestine
Triglycerides
Monoglycerides,
glycerol, fatty acids
ss
io
n
:2
02
Large peptides
SUMMARY
The digestive system of humans consists of an alimentary canal and associated digestive glands. The alimentary
canal consists of the mouth, buccal cavity, pharynx, oesophagus, stomach, small intestine, large intestine, rectum
and the anus. The accessory digestive glands include the salivary glands, the liver (with gall bladder) and the
pancreas. Inside the mouth the teeth masticates the food, the tongue tastes the food and manipulates it for
proper mastication by mixing with the saliva. Saliva contains a starch digestive enzyme, salivary amylase that
digests the starch and converts it into maltose (disaccharide). The food then passes into the pharynx and enters
the oesophagus in the form of bolus, which is further carried down through the oesophagus by peristalsis into the
stomach. In stomach mainly protein digestion takes place. Absorption of simple sugars, alcohol and medicines
also takes place in the stomach.
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\02-DIGEST-E.P65
Aminopeptidase
Trypsinogen
21
Small intestine
0-
Enteropeptidase
or enterokinase
Se
34
E
ALLEN
Pre-Medical : Biology
35
E
Nucleosidases
(DNase and RNase)
Nucleases
Pancreatic Lipase
Nucleotideses,
Stimulation of peristalisis etc.
Amylase
HCl
Lactase,
Procarboxypeptidase,
Gastric Lipase
Maltase,
fat-soluble vitamins
Trypsinogen,
Rennin
(Amylase)
Chymotrypsinogen,
Pepsin
Ptaylin
Pancreatic Secretion
Gastric Secretion
Salivary Secretion
Sympathetic
(Decreases secretion
of digestive juices)
Parasympathetic
(Increases secretion
of digestive juices)
Sucrase,
and Absorption of
Intes tinal lipase
Emulsifiation of Fats
Dipeptidase
21
Bile Secretion
002
:2
n
io
Secretion for Digestion
Se
ss
DIGESTIVE SYSTEM
Structure
N
E
R
V
O
U
S
S
Y
S
T
E
M
Oesophagus
Pharynx
Mouth
Succus Entericus
Intestinal Peristalsis
Gastric movements.
Peristalsis in oesophagus
Mastication of food
M
E
C
H
A
N
I
C
Liver, Gall bladder,
Pancreas, Salivary glands
Rectum Anal canal
Large intestine (colon)
Small intestine
Stomach
Ascending
Ileum
Jejunum
Duodenum
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\02-DIGEST-E.P65
Summary of Digestive System
Transverse
Descending
Sigmoid
The chyme (food) enters into the duodenum portion of the small intestine and is acted on by the pancreatic
juice, bile and finally by the enzymes in the succus entericus, so that the digestion of carbohydrates, proteins and
fats is completed. The food then enters into the jejunum and ileum portions of the small intestine. Carbohydrates
are digested and converted into monosaccharides like glucose. Proteins are finally broken down into amino
acids. The fats are converted to fatty acids and glycerol. The digested end products are absorbed into the body
through the epithelial lining of the intestinal villi. The undigested food (faeces) enters into the caecum of the
large intestine through ileo-caecal valve, which prevents the back flow of the faecal matter. Most of the water is
absorbed in the large intestine. The undigested food becomes semi-solid in nature and then enters into the
rectum, anal canal and is finally egested out through the anus.
Heterodont
(Different types of teeth
endodermal
MP
MUSCLES
HISTOLOGY
NERVE
ss
E
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\02-DIGEST-E.P65
APICAL FOR A MEN
PERIODANTAL LIGAMENT
· GASTRIC GLANDS
· · · MULTILAYERED
EPITHELIUM
Brunner's glands
Peyers patches
Panethcells
Pyloric
Orifice
Pyloric sphincter
U
M
:2
Food move downward due to regular contraction
and relaxation of oesophagus called peristalsis
Cardiac/Gastrooesophagial sphincter
H
0-
S
U
G
A
02
Aleum
Jejunum
G
Opens on posteriomedial
aspect of caecum
ith
W mm
O
Stomach
consist
of
Fundus part
Cardiac part
Cardiac orifice
21
Longest oesophagus is in Giraffe
S
E
P
GULLET
Common passage
for food and air
Dorsal opening which
continues into oesophagus
· Secret maximum saliva
SUBMANDIBULAR GLANDS
O
X
N
SUBLINGUAL GLANDS
· Smallest salivary glands below tongue
Digestive glands are absent but starch continue
to digest upto the last end of oesophagus. Salivary
amylase is inactivated by HCl in stomach
Length of oesophagus depend on length of
neck of organism
O
RY
A
PH
r
cu
esser
CANL
BODY
NAL
n
Blunt Villi are in duodenum
whereas long and pointed in
jejunum and ileum
CEMENT-65% inorganic substance
PULP-CAVITY
io
Villi
Crypts of Lieberkuhn
UCT
W
H
'S D
o n ARTON duct)
y
ge s t lvar
sa
-DUCT
PAROTID
PAROTID - GLAND
· Largest salivary glands
· Viral infection called mumps
· Present near ear
· Secret ptyalin (Salivary amylase)
3. Intestinal phase
2. Gastric phase
Cranial nerves
on of gastric juice is mediated by X pair of
nerves ¯ secretion of gastric juice. Secreti
secretion of Gastric juice and sympathetic
1. Cephalic phase - Parasympathetic nerves ­
Three phases of release of Gastric juice are :-
+ rest other (enzymes, hormones, mucus)
Consists of 99.5% water + 0.2% to 0.3% HCl
GASTRIC JUICE
food mainly contain protein
· Ptyalin is not present in carnivores as their
because its food mainly contain cellulose
· Ptyalin is not present in saliva of rabbit
SALIVA + FOOD = BOLUS
Maltose + dextrin
STARCH (30%)
Lysozyme
bactericidal in nature
Thiocynate
Glycoprotein mucin-lubricate food particles
Salivary amylase
SALIVARY - GLAND
Secrete Saliva which contain - 99.5%
water and 0.5% electrolytes + other
substances
Pre-Medical : Biology
ROOT
NECK
ENAMEL-96% inorganic substance
DENTINE-69% inorganic substance
CANALICULI
STRUCTURE OF TOOTH :-
OF
CROWN
SEROSA
When fats + lymph tissues are
deposited called ommentum
SEROSA
PLEXUS
MUSCLES
MP
PLEXUS
NF
BV
LV
P R O
P R I A
S
M U C O S A
MUSCLES
SEROSA
ALIMENTARY CANAL
Tunica
adventia
of white
fibrous CT
N A
L A R I
Se
Tee
ora th in
l ca
vity
also contain highly muscular tongue;
attached to floor of oral cavity by
frenulum. Contain papillia.
EPIGLOTTIS
(Cartilagenous flap prevent entry of food into Glottis)
Opening of windpipe (Glottis)
Thecodont
(Teeth in sockets)
NF
NF
BV
BV
MP LV
MP
LV
OBLIQUE
MUSCLES MEISSNER'S
AUERBACH'S
LONGITUDINAL
CIRCULAR
NF
BV
LV
L A M I
M U S C U
RECTUM
ANAL CANAL ectodermal
ANUS
SOFT PALATE
HARD-PALATE
are incisors, canines,
· Lips are movable as
premolars, molars)
Lower lip
orbicularis oris
(with dental formula
muscles are present.
2123/2123)
· Lips are immovable in WHALE and DUCK
BILLED PLATYPUS
Diphyodont
ORIGIN OF ALIMENTARY CANAL
(Teeth appear twice
in life time)
MOUTH
ectodermal
Upper lip
Outer part with sebaceous glands
Inner part with serous glands
guarded by lips in front.
MOUTH is a transverse slit like aperture
ure
vat
SUBMUCOSA
R
COMPARATIVE
T
A NUM
MUCOSA
RV
CU
Consist of hardest substance of
animal-enamel (contain maximum
amount of inorganic substances)
(L
REATE R
G
en rea t
tu er
m
36
ALLEN
N
DUODE
ALLEN
Pre-Medical : Biology
ANSWER KEY
Que.
3
2
4
4
5
1
11
2
12
3
13
4
14
1
15
1
A ns.
1
2
2
4
3
3
4
4
Que.
Ans.
1
2
2
2
3
2
Que.
1
2
2
3
1
2
Que.
A ns.
B EGINNE R 'S B OX-2
BEGINNER'S BOX-3
B EGINNE R 'S B OX-4
B EGINNE R 'S B OX-5
B EGINNE R 'S B OX-6
A ns.
Que.
A ns.
Que.
A ns.
Que.
A ns.
7
1
8
1
5
2
6
1
7
2
8
1
4
3
5
2
6
3
7
2
3
1
4
3
5
3
6
2
2
1
3
1
4
1
5
1
1
1
2
3
3
2
4
1
1
1
2
3
3
1
4
2
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\02-DIGEST-E.P65
Se
ss
io
n
:2
02
B EGINNE R 'S B OX-7
Que.
6
3
E
9
1
10
3
8
2
9
1
10
3
7
2
8
1
9
3
10
1
6
4
7
1
8
1
9
1
10
3
5
3
6
4
7
4
8
1
9
4
10
4
5
4
6
4
7
3
8
2
9
4
10
4
21
2
1
0-
B EGINNE R 'S B OX-1
1
1
A ns.
37
ALLEN
Pre-Medical : Biology
Build Up Your Understanding
EXERCISE-I (Conceptual Questions)
10.
3.
4.
Which cells of mucous layer of stomach secrete
pepsinogen
(1) Chief cell
(2) Goblet cell
(3) Parietal cell
(4) Oxyntic cell
DS0004
Innermost layer of mucosa is made up of columnar
epithelium except :(1) Oesophagus
(2) Duodenum
(3) Intestine
(4) Stomach
DS0005
How many teeth in man grows twice in life :
(1) 32
(2) 28
(3) 20
(4) 12
DS0006
(2) Cells of Acini and Islets of langarhans resp.
(3) Istets of langeshans and cells of Acius resp.
(4) None of these.
DS0012
11.
12.
13.
14.
7.
8.
9.
(3) Duodenum
(4) Thyroid
Which substance destroy the harmful bacteria(1) Cerumin
(2) Chyme
(3) HCl
(4) Secretin
One of the following is not a constituent of saliva :(1) Bicorbonate
(2) Lysozyme
(3) Glucose
(4) Immunoglobulin
DS0015
What statement is wrong about bile ?
(2) Is stored in the gall bladder
(3) Is important only for normal digestion of sugar
(4) None of above
DS0016
15.
Which of the following is a function of gall bladder:(1) Deamination
Se
(2) Bile storage
(3) Synthesis of plasma protein
In human being sphincter of Oddi is situated in :(1) Common bile duct
(2) Ampulla of vater
(3) Main pancreatic duct (4) Common hepatic duct
DS0009
Ptyalin is secreted by(1) Stomach
(3) Pancreas
(2) Liver
(1) Is necessary for fat digestion
DS0007
DIGESTIVE GLANDS
(1) Pancreas
DS0014
n
io
In human which teeth help in cutting ?
(1) Canine
(2) Incisor
(4) Premolar
(3) Molar
ss
6.
C-shaped widest part of intestine
DS0013
:2
5.
Enamel of teeth is secreted by :(1) Ameloblast
(2) Odontoblast
(3) Osteoblast
(4) Osteoclast
DS0002
(1) Islets of langerhans
0-
2.
Parietal cells of mucosa in stomach secretes :
(2) Pepsin
(1) Mucin
(3) HCl
(4) All of the above
DS0001
02
1.
In pancreas, pancreatic juice and hormone are
secreted by-
21
ALIMENTARY CANAL (MOUTH TO ANUS)
(2) Salivary gland
(4) Bile
DS0010
Ptyalin, an enzyme work in saliva in (1) Alkaline medium
(2) almost neutral medium
(3) Acidic medium
(4) all media
(4) Storage of fat soluble vitamin
DS0017
16.
Crypts of Leiberkuhn are found in between the villi.
They secrete :
(1) Glucagon
(2) Succus entericus
(3) Insulin
(4) None
DS0018
17.
Parotid salivary glands are present :
(1) Below the tongue
(2) Below the ears
(3) Below the eye orbits
(4) In the angle between two jaws
DS0011
DS0019
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38
E
ALLEN
18.
Pre-Medical : Biology
Specific cells found in liver are :
(1) Enterocyte cells
(2) Beta cells
(3) Hepatic cells
(4) Islets of Langerhans
DS0021
39
26.
Digestion of carbohydrate is affected by(1) Amylopsin
(2) Lipase
(3) Erepsin
(4) Pepsin
DS0030
27.
Trypsin is secreted by(1) Pancreas
(3) Liver
PHYSIOLOGY OF DIGESTION AND OTHERS
(2) Stomach
(4) Ileum
DS0031
19.
Casein present in milk,which is (1) bacterium
(2) sugar
(3) protein
(4) fat
28.
Proteins are broken down into amino acids in(1) Buccal cavity
(2) Stomach
(3) Intestine
(4) Rectum
DS0032
29.
Which reserve food is consumed by man during
starvation :(1) Fat
(2) Protein
(3) Glucose
(4) Vitamin
DS0033
30.
Ptyalin cannot work in stomach, because it
becomes(1) Inactive due to HCl
(2) Inactive due to renin
(3) Inactive due to pepsin
(4) None of these
DS0034
21.
Liver cells secrete(1) amylopsin
(3) lipase
Peristaltic movements found in different parts of
alimentary canal. In which one of these there is least
peristalsis(1) Stomach
(2) Duodenum
(3) Rectum
(4) Oesophagus
DS0026
31.
ss
Milk protein is curdled into calcium paracaseinate
by (1) Maltose
(2) Rennin
(3) Trypsin
(4) lactose
DS0027
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
Se
23.
io
n
:2
22.
(2) trypsin
(4) bile and no enzyme
DS0025
0-
Amylase enzyme acts on the (1) Starch
(2) Protein
(3) Fat
(4) Cane sugar
DS0024
02
20.
21
DS0023
E
24.
What is the important function of bile(1) For digestion by emulsification of fats
(2) Elimination of excretory products
(3) For digestion by enzymes
(4) Coordination of digestive activities
DS0035
32.
The enzyme invertase hydrolyses(1) Glucose into sucrose
Some proteolytic enzymes are(1) Trypsin, Erepsin, Pepsin
(2) Amylase, Lipase, Zymase
(3) Ampylopsin, Steapsin, Ptyalin
(4) Urease, Dehydrogenase, Zymase
DS0036
(2) Sucrose into glucose and fructose
(3) Starch into maltose
33.
Succus entericus is secreted by(1) Gastric glands
(2) Islets of langerhans
(3) Crypts of lieberkuhn & Brunner's gland
(4) Goblet cells
DS0037
34.
Glycogen is stored in(1) Blood
(3) Lungs
(4) Starch into sucrose
DS0028
25.
Amino acids are absorbed in(1) Blood capillaries of villi
(2) Wall of rectum
(3) lacteals and blood capillaries of villi
(4) lacteals of villi
DS0029
(2) Liver
(4) Kidney
DS0038
35.
36.
ALLEN
Pre-Medical : Biology
Chymotrypsin is(1) Proteolytic enzyme
(3) Vitamin
45.
Function of HCl in stomach is to(1) Kill micro-organism of food
(2) Facilitate absorption of food
(3) Dissolve hormones secreted by gastric glands
(4) Active trypsinogen to trypsin
DS0049
46.
Enzyme maltase in human gut acts on food at a
pH of (1) More than 7to change starch into maltose.
(2) Less than 7 to change starch into maltose.
(3) More than 7 to change maltose into glucose.
(4) Less than 7 to change maltose into glucose.
DS0050
Simple sugar of blood is(1) Dextrin
(2) Lactose
(3) Sucrose
(4) Glucose
(2) Fat digestive enzyme
(4) Hormone
DS0039
Emulsification of fats by bile takes place in(1) Duodenum
(2) Liver
(3) Stomach
(4) Intestine
DS0040
37.
Absorption of digested food chiefly occurs in(1) Stomach
(2) Colon
(3) Small Intestine
(4) Large Intestine
DS0041
38.
The enzyme trypsinogen is secreted from(1) Duodenum
(2) Pancreas
(3) Liver
(4) Stomach
DS0042
47.
39.
Enzyme pepsin acts upon food at a pH of about(1) 3 to split proteins
(2) 2 to split carbohydrate
(3) 7 to change protein into peptones
(4) 2 to change protein in amino acids
DS0043
48.
40.
Our food mainly contains(1) Carbohydrates
(2) Cellulose
(3) Sucrose
(4) Glucose
DS0051
21
002
:2
49.
n
DS0044
io
Which one is differ from the category of other three(1) Gastrin
(2) Glucagon
(3) Secretin
(4) Ptyalin
DS0045
50.
42.
43.
44.
A carbohydrate splitting enzyme is secreted by (1) Liver
(2) Zymogen cells of gastric glands
(3) Spleen
(4) Crypts of Lieberkuhn
DS0046
Stomach is the main site for the digestion of (1) Fats
(2) Carbohydrate
(3) Protein
(4) All of these
DS0047
The hormone involved in the discharge of pancreatic
juice in mammal is called(1) Gastrin
(2) Secretin
(3) Secretin & CCK
(4) Enterogasterone
DS0048
Enterokinase stimulates which of the following(1) Pepsinogen
(2) Trypsin
(3) Pepsin
(4) Trypsinogen
DS0053
Maximum digestion of food take place in –
(1) Stomach
(3) Colon
Se
ss
41.
During prolonged starvation, body derives nutrition
from storage of (1) Liver and adipose tissue
(2) Spleen
(3) Liver and lungs
(4) Subcutaneous fat and Pancreas
DS0052
(2) Jejunum
(4) Duodenum
DS0054
51.
Absence of which of these in bile will make fat
digestion difficult(1) Cholesterol
(2) Bile salts
(3) Pigment
(4) Acids
DS0055
52.
Pancreatic juice is released into(1) Duodenum
(2) Ileum
(3) Stomach
(4) Jejunum.
DS0056
53.
The enzyme that catalyse the changing of emulsified
fats to fatty acids and glycerol is(1) Pepsin
(2) Lipase
(3) Amylase
(4) Sucrose
DS0057
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
40
E
ALLEN
54.
Point out the odd one(1) Rennin
(3) Calcitonin
Pre-Medical : Biology
63.
(2) Secretin
(4) Oxytocin
DS0058
Muscular contraction of alimentary canal are(1) Circulation
(2) Deglutition
(3) Churning
(4) Peristalsis
DS0068
65.
Fatty acids and glycerol are first absorbed by(1) Lymph vessels
(2) Blood
(3) Blood capillaries
(4) Hepatic portal Vein
DS0069
66.
During prolonged fasting(1) First fats are used up, followed by carbohydrate
from liver and muscles, and protein in the end
(2) First carbohydrate are used up, followed by fat
and proteins towards end
(3) First lipids, f ollo wed by proteins and
carbohydrates towards end.
(4) None of the above
DS0070
(2) Liver
(4) Blood
DS0060
57.
64.
Cholecystokinin is secretion of
(1) Duodenum that causes contraction of gall bladder
(2) Goblet cells of ileum stimulates secretion of
succus entricus
(3) Liver and controls secondary sex characters
(4) Stomach that stimulates pancreas to release
juice
DS0061
Enzyme trypsinogen is changed to trypsin by
(1) Gastrin
(2) Enterogastrone
(3) Enterokinase
(4) Secretin
DS0062
59.
Castle's intrinsic factor is connected with internal
absorption of(1) Pyridoxine
(2) Riboflavin
(3) Thiamine
(4) Cobalamine
DS0063
60.
Maximum number of enzymes occur in(1) Omnivorous
(2) Herbivores
(3) Carnivores
(4) None of the above
DS0064
61.
Cholesterol is synthesized in(1) Brunner's gland
(2) Liver
(3) Spleen
(4) Pancreas
67.
Which of the following is absorbed in ileum(1) Fat
(2) Bile salts
(3) Vit-K
(4) Glucose
DS0071
68.
Which food substance is absorbed, without digestion(1) Carbohydrates
(2) Proteins
(3) Vitamins
(4) Fats
DS0072
69.
Mucus is secreted by the :(1) Stomach
(2) Duodenum
(3) Large intestine
(4) All of the above
DS0073
70.
Water absorption is mainly occur in :(1) Colon
(2) Intestine
(3) Stomach
(4) Appendix
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
E
Se
ss
io
n
:2
58.
21
Bile is formed in(1) Gall bladder
(3) Spleen
DS0067
0-
56.
Pancreatic lipase acts upon(1) Glycogen
(2) Triglycerides
(3) Dissacharides
(4) Polypeptides
DS0059
DS0065
62.
Rennin acts on(1) Milk changing casein into calcium paracaseinate
at 7.2 - 8.2 pH
(2) Proteins in stomach
DS0074
71.
(3) Fat in intestine
(4) Milk, changing casein into calcium paracaseinate
at 1-3 pH
DS0066
Lacteals take part in (1) Digestion of milk
(2) Absorption of fat
(3) Digestion of lactic acid
(4) None of the above
02
55.
41
Which of the following absorbed in proximal
intestine:(1) Iron
(2) Sodium
(3) Bile salts
(4) Vitamin B12
DS0075
74.
Lactose composed of :(1) Glucose + galactose (2) Glucose + fructose
(3) Glucose + glucose
(4) Glucose + mannose
DS0078
75.
If for some reason the parietal cells of the gut
epithelium become partially non-functional, what
is likely to happen ?
(1) The pH of stomach will fall abruptly
(2) Steapsin will be more effective
(3) Proteins will not be adequately hydrolysed by
pepsin into proteoses and peptones
(4) The pancreatic enzymes and specially the trypsin
and lipase will not work efficiently
DS0079
In stomach after physical and chemical digestion
food is called:(1) Chyme
(2) Chyle
(3) Amino acid
(4) Bolus
DS0080
(3) Sucrose
82.
83.
84.
85.
86.
n
80.
Stool of a person contain whitish grey colour due
to malfunction of which type of organ:
(1) Pancreas
(2) Spleen
(3) Kidney
(4) Liver
DS0084
Glucose and galactose unite to form
(1) Maltose
(2) Sucrose
(3) Isomaltose
(4) Lactose
DS0088
Gastric enzyme pepsin acts only in acidic medium
with in a limited pH concentration. It varies:
(1) 1.20 to 1.80
(2) 1.00 to 1.50
(3) 2.00 to 2.50
(4) 1.50 to 2.60
DS0089
Stomach in vertebrates is the main site for digestion
of :
(1) Proteins
(3) Fats
ss
In mammals, milk is digested by action of(1) Rennin
(2) Amylase
(3) Intestinal bacteria
(4) Invertase
DS0083
Hydrolysis of lipid yields :(1) Fats
(2) Fatty acids and glycerol
(3) Mannose and glycerol
DS0087
87.
A person who is eating rice. His food contains
(1) Cellulose
(2) Starch
(3) Lactose
(4) Protein
DS0082
79.
(4) Amino acid
DS0086
(4) Maltose and fatty acid
io
78.
Fully digested food reaches to liver by
(1) Hepatic portal vein (2) Hepatic artery
(3) Hepatic vein
(4) All the above
DS0081
If all the peptide bonds of protein are broken, then
the remaining part is :(1) Amide
(2) Oligosaccharide
(3) Polypeptide
Se
77.
(4) Galactose
DS0085
:2
76.
Which of the following is a dissacharide :
(1) Glucose
(2) Fructose
(2) Carbohydrates
(4) Nucleic acids
DS0090
The chief function of bile is to :
(1) Digest fat by enzymatic action
(2) Emulsify fats for digestion
(3) Eliminate waste products
(4) Regulate digestion of proteins
DS0091
88.
The toxic substance are detoxicated in the human
body by :
(1) Lungs
(2) Kidneys
(3) Liver
(4) Stomach
DS0092
89.
The end product of carbohydrate metabolism is :
(1) CO2 and H2O
(2) NH3 and CO2
(3) NH3 and H2O
(4) CO2
DS0093
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
Jaundice is a disorder of :
(1) Skin and eyes
(2) Digestive system
(3) Circulatory system
(4) Excretory system
DS0077
81.
21
73.
Substances which are not related with hepatic portal
circulation :(1) Amino acid
(2) Fatty acid
(3) Glucose
(4) Fructose
DS0076
0-
72.
ALLEN
Pre-Medical : Biology
02
42
E
ALLEN
Pre-Medical : Biology
End products of protein hydrolysis are :
(1) Mixture of amino acids
(2) Sugars
(3) Peptides
(4) 25 amino acids
DS0095
Ptyalin is an enzyme of
(1) Salivary juice
(2) Pancreatic juice
(3) Intestinal juice
(4) None of these
DS0096
92.
93.
The hormone 'secretin' stimulates secretion of
(1) Pancreatic juice
(2) Intestinal juice
(3) Salivary juice
(4) Gastric juice
DS0097
Which one of the following amino acids is not found
in proteins ?
(1) Arginine
(2) Ornithine
(3) Aspartic acid
(4) Tyrosine
DS0098
95.
Succus entericus is also called are:
(1) Gastric juice
(2) Intestinal juice
(3) Bile juice
(4) Saliva
DS0099
96.
Just as hydrochloric acid is for pepsinogen, so is
the:
(1) haemoglobin to oxygen
(2) enterokinase to trypsinogen
(3) bile juice to fat
(4) glucagon to glycogen
DS0100
n
io
ss
Se
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
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97.
Where the lysozymes are found :
(1) In saliva and tears both
(2) In tears
(3) In saliva
(4) In mitochondria
DS0101
98.
100. Pancreatic juice is :
(1) Alkaline in nature
(2) Acidic in nature
(3) Neutral in nature
(4) Both acidic and alkaline in nature
DS0104
101. Bilirubin and Biliverdin are present in :
(1) Pancreatic Juice
(2) Saliva
(3) Bile juice
(4) Intestinal juice
DS0105
102. The amount of gastric juice secreted per day from
man's stomach is about :
(1) 500 ml. to 1000 ml
(2) 2000 ml to 3000 ml
(3) 100 ml to 500 ml
(4) 10 ml to 15 ml
DS0106
103. The function of enterogasterone hormone is :
(1) to control excretion
(2) to inhibit gastric juice secretion
(3) regulate the absorption of food
(4) to stimulate gastric glands to release gastric juice
DS0107
:2
94.
Trypsin differs from pepsin because it digests :
(1) Carbohydrate in alkaline medium in stomach
(2) Protein, in alkaline medium in stomach
(3) Protein, in acidic medium of stomach
(4) Protein, in alkaline medium in duodenum
DS0103
21
91.
99.
0-
The muscular contraction in the alimentary canal
is known as :
(1) Systole
(2) Diastole
(3) Peristalsis
(4) Spasm
DS0094
02
90.
43
The major site of protein breakdown to form free
amino acids, is in the
(1) Kidney
(2) Spleen
(3) Intestine
(4) Bone-marrow
DS0102
104. What is the common passage for bile and pancreatic
juices
(1) Ampulla of Vater
(2) Ductus Choledochus
(3) Duct of Wirsung
(4) Duct of Santorini
DS0108
105. Pepsinogen is secreted from :
(1) argentaffin cells
(2) goblet cells
(3) chief cells
(4) parietal cells
DS0109
106. Cells of the pancreas is not digested by their own
enzymes because :
(1) enzymes are secreted in inactive form
(2) cells are lined by mucous membrane
(3) enzymes are released only when needed
(4) none of the above
DS0110
ALLEN
Pre-Medical : Biology
0-
21
115. Another substance of the category of glucose,
sucrose and maltose is(1) Myoglobin
(2) Starch
(3) Amino acids
(4) Haemoglobin
DS0119
116. A person with bleeding gums should daily take(1) Milk
(2) Carrots
(3) Lemons
(4) Butter
DS0120
117. Rickets is a disease of which category(1) Infective disease
(2) Deficiency disease
(3) Communicable disease
(4) Inheritable disease
DS0121
118. Thiamine is another name for(1) Vit B2
(2) Vit A
(3) Vit B1
(4) Vit B Complex
DS0122
119. Vit D is also called(1) Calciferol
(2) Ascorbic acid
(3) Retinol
(4) Folic Acid
DS0123
120. In mammals carbohydrate are stored in the form
of(1) Lactic acid in muscles
(2) Glycogen in liver and muscles
(3) Glucose in liver and muscles
(4) Glycogen in liver and spleen
DS0124
121. Which pairing is not correct(1) Vit D -Rickets
(2) Vit K - Sterility
(3) Thiamine - Beri-Beri (4) Niacin - Pellagra
DS0125
122. Beri-Beri, Scurvy and Rickets are respectively
caused by deficiency of (1) B, D & C
(2) B, C & D
(3) D, B & A
(4) A, D & C
DS0127
123. Vit K is a required for(1) Change of Prothrombin to thrombin
(2) Synthesis of Prothrombin
(3) Change of Fibrinogen to Fibrin
(4) Formation of thromboplastin
DS0128
124. Vitamin which induces maturation of R.B.C.:(1) B1
(2) A
(3) B12
(4) D
DS0131
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
Se
ss
io
n
:2
107. Secretin :
(1) Stimulates enzymes secretion by pancreas,
inhibits acid secretion in stomach, stimulates gall
bladder
(2) Stimulates bicarbonate secretion by pancreas,
inhibits acid secretion in stomach, stimulates
bicarbonate secretion by liver
(3) Stimulates acid secretion in stomach, potentiates
action of CCK, inhibits intestinal movement
(4) Stimulates gall bladder, inhibits acid secretion in
stomach, stimulates bicarbonate secretion by
pancreas
DS0111
108. Vitamins are (1) Inorganic substances and can't be synthesized by
animals.
(2) Inorganic substances and can be synthesized by
animals.
(3) Organic substances which cannot mostly be
synthesized by animals.
(4) Organic substances which can mostly be
synthesized by animals.
DS0112
109. Which should not be eaten too much during hot
months(1) Vitamins
(2) Fats
(3) Mineral salts
(4) Proteins
DS0113
110. To get ample supply of carbohydrates, one should
eat (1) Meat
(2) Gram
(3) Carrots
(4) Rice
DS0114
111. Protein are mainly required in the body for(1) Growth
(2) Repair
(3) Both of these
(4) None of these
DS0115
112. A person deficient in Rhodopsin (visual pigment)
should take(1) Tomatoes
(2) Radish
(3) Carrot
(4) Guavas
DS0116
113. Rickets is caused by the deficiency of(1) Vit A
(2) Vit C
(3) Vit D
(4) Vit B
DS0117
114. Pernicious anaemia is caused by deficiency of
vitamin(1) C
(2) B1
(3) B12
(4) B6
DS0118
02
44
E
ALLEN
Pre-Medical : Biology
130. In adults the deficiency of vitamin D causes :
(1) Rickets
(2) Beri-beri
(3) Scurvy
(4) Osteomalacia
DS0137
131. Which of the following vitamin synthesise in animal
body by bacteria :
(1) C
(2) A
(3) E
(4) B12
DS0138
132. Marasmus disease is caused due to :
(1) Protein deficiency
(2) Obesity
(3) Dwarfism
(4) Deficiency of vitamins
DS0139
133. Which of the following does not belong to vitamin B
group :
(1) Riboflavin
(2) Niacin
(3) Cyanocobalamine
(4) Tocopherol
DS0140
134. Certain B vitamins are:
(1) Enzymes
(2) Co-enzymes
(3) Hormone
(4) Digestive substance
DS0141
135. Deficiency of thiamine causes :
(1) Beri-beri
(2) Rickets
(3) Caries
(4) Pellagra
DS0142
136. Vitamin C is helpful in the :
(1) Formation of visual pigment
(2) Growth of bones
(3) Treatment of pernicious anaemia
(4) Wound healing
DS0143
125. Which one is wrong pair :(1) Scurvy – Vitamin C
(2) Rickets – Vitamin D
(3) Night blindness – Vitamin A
(4) Beriberi – Vitamin K
126. Which one is correctly matched :(1) Vit. E – Tocoferol
(2) Vit. D – Riboflavin
(3) Vit. B – Calciferol
(4) Vit. A – Thiamine
DS0132
DS0133
127. Vitamin–C is :–
(1) Ascorbic acid
(3) Phosphoric acid
2
3
4
5
6
3
1
1
1
3
Que.
16
17
18
19
Ans.
2
2
3
3
Que.
31
32
33
34
35
0-
02
:2
n
io
1
Ans.
ANSWER KEY
8
9
10
11
12
13
14
15
2
2
2
2
2
3
3
3
3
2
20
21
22
23
24
25
26
27
28
29
30
1
4
3
2
2
1
1
1
3
1
1
36
37
38
39
40
41
42
43
44
45
Se
7
ss
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Que.
21
(2) Citric acid
(4) Glutamic acid
DS0134
128. Which one of the following is the correct matching
of a vitamin, its nature and its deficiency disease :
(1) Vitamin K–Fat soluble–Beri–Beri
(2) Vitamin A–Fat soluble–Beri–Beri
(3) Vitamin K– Water soluble–Pellagra
(4) VitaminA – Fat soluble–Night blindness
DS0135
129. Scurvy disease is due to :
(1) Presence of h-factor in blood
(2) Deficiency of vitamin E
(3) Virus
(4) Deficiency of vitamin C
DS0136
EXERCISE-I (Conceptual Questions)
45
Ans.
1
1
3
2
1
1
3
2
1
1
4
4
3
3
1
Que.
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Ans.
3
4
1
4
4
2
1
2
1
2
2
1
3
4
1
Que.
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
Ans.
2
4
2
4
1
2
2
3
4
2
1
2
2
1
3
Que.
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
Ans.
1
1
2
1
4
3
4
2
4
4
1
2
3
1
3
Que.
91
1
92
1
93
1
94
2
95
2
96
2
97
1
98
3
99
4
100
1
101
3
102
2
103
2
104
1
105
3
107
108
109
110
111
112
113
114
115
116
117
118
119
120
2
3
2
4
3
3
3
3
2
3
2
3
1
2
122
123
124
125
126
127
128
129
130
131
132
133
134
135
2
2
3
4
1
1
4
4
4
4
1
4
2
1
Ans.
Que. 106
Ans.
1
Que. 121
Ans.
2
Que. 136
Ans.
4
ALLEN
Pre-Medical : Biology
AIPMT/NEET
EXERCISE-II (Previous Year Questions)
5.
AIPMT 2007
1.
A young infant that feed entirely on mother's milk
which is white in colour but the stools which the infant
Which one of the following is a fat-soluble vitamin
and its related deficiency disease ?
(1) Calciferol
– Pellagra
(2) Ascorbic acid
– Scurvy
(3) Retinol
– Xerophthalmia
(4) Cobalamine
– Beri-beri
passes out is quite yellowish. This yellow colour due
to ?
(1) Pancreatic juice poured into duodenum
(2) Intestinal juice
(3) Bile pigments passed through bile juice
(4) Undigested milk protein casein
DS0145
AIPMT 2008
2.
Which one of the following is the correct matching
of the site of action on the given substrate, the enzyme
acing upon it and the end product ?
(1) Small intestine:Proteins
(2) Stomach : Fats
Pepsin
Lipase
DS0149
6.
Amino acids
AIPMT 2015
micelles
7.
Trypsin
:2
02
0-
µAmylase
(4) Small intestine : Starch
Disaccharide (Maltose)
DS0146
8.
n
What will happen if the secretion of parietal cells
of gastric glands is blocked with an inhibitor ?
(1) In the absence of HCl secretion, inacitve
pepsinogen is not converted into the active
enzyme pepsin
(2) Enterokinase will not be released from the
duodenal mucosa and so trypsinogen is not
converted to trypsin
(3) Gastric juice will be deficient in chymosin
(4) Gastric juice will be deficient in pepsinogen
DS0147
NEET-I 2016
In the stomach, gastric acid is secreted by the :-
io
(3) peptic cells
ss
Se
DS0154
(1) gastrin secreting cells (2) parietal cells
(4) acidic cells
DS0155
9.
Which of the following guards the opening of
hepatopancreatic duct into the duodenum ?
(1) Semilunar valve
(2) Ileocaecal valve
(3) Pyloric sphincter
(4) Sphincter of Oddi
AIPMT 2009
4.
Gastric juice of infants contains :(1) nuclease, pepsinogen, lipase
(2) pepsinogen, lipase, rennin
(3) amylase, rennin, pepsinogen
(4) maltase, pepsinogen, rennin
21
(3) Duodenum : Triglycerides
monoglycerides
3.
AIPMT 2014
The initial step in the digestion of milk in humans
is carried out by ?
(1) Lipase
(2) Trypsin
(3) Rennin
(4) Pepsin
DS0153
DS0156
Which one of the following pairs of food components
in humans reaches the stomach totally undigested?
(1) Starch and cellulose
(2) Protein and starch
(3) Starch and fat
(4) Fat and cellulose
DS0148
10.
NEET-II 2016
Which hormones do stimulate the production of
pancreatic juice and bicarbonate?
(1) Cholecystokinin and secretin
(2) Insulin and glucagon
(3) Angiotensin and epinephrine
(4) Gastrin and insulin
DS0157
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46
E
ALLEN
Pre-Medical : Biology
NEET(UG) 2017
(1) Stomach
(2) Kidneys
(3) Intestine
(4) Heart
(a) Crypts of Lieberkuhn (i) Pancreas
Which cells of "Crypts of Lieberkuhn" secrete
antibacterial lysozyme ?
(1) Paneth cells
(2) Zymogen cells
(3) Kupffer cells
(4) Argentaffin cells
DS0160
The hepatic portal vein drains blood to liver
from :
18.
DS0256
13.
(b) Glisson's Capsule
(ii) Duodenum
Which of the following options best represents the
(c) Islets of Langerhans
(iii) Small intestine
enzyme composition of pancreatic juice ?
(d) Brunner's Glands
(iv) Liver
Select the correct option from the following :
(a)
(b)
(c) (d)
(1) (iii)
(i)
(ii) (iv)
(2) (ii)
(iv)
(i)
(iii)
(3) (iii)
(iv)
(i)
(ii)
(4) (iii)
(ii)
(i)
(iv)
DS0258
NEET(UG) 2019 (ODISHA)
(1) amylase, pepsin, trypsinogen, maltase
(2) peptidase, amylase, pepsin, rennin
(3) lipase, amylase, trypsinogen, procarboxypeptidase
(4) amylase, peptidase, trypsinogen, rennin
io
n
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
E
16.
Which of the following terms describe human
dentition ?
(1) Thecodont, Diphyodont, Homodont
(2) Thecodont, Diphyodont, Heterodont
(3) Pleurodont, Monophyodont, Homodont
(4) Pleurodont, Diphyodont, Heterodont
DS0165
Se
15.
ss
NEET(UG) 2018
Match the items given in column I with those in
column II and choose the correct option :
02
19.
:2
14.
DS0161
A baby boy aged two years is admitted to play school
and passes through a dental check - up. The dentist
observed that the boy had twenty teeth. Which teeth
were absent?
(1) Canines
(2) Pre-molars
(3) Molars
(4) Incisors
DS0162
21
12.
NEET(UG) 2019
Identify the cells whose secretion protects the lining
of gastro-intestinal tract from various enzymes :(1) Chief Cells
(2) Goblet Cells
(3) Oxyntic Cells
(4) Duodenal Cells
DS0257
Match the following structures with their respective
location in organs :
17.
0-
11.
20.
Column-I
Column-II
(a) Rennin
(i) Vitamin B12
(b) Enterokinase
(ii) Facilitated transport
(c) Oxyntic cells
(iii) Milk proteins
(d) Fructose
(iv) Trypsinogen
(1) a-iii, b-iv, c-ii, d-i
(2) a-iv, b-iii, c-i, d-ii
(3) a-iv, b-iii, c-ii, d-i
(4) a-iii, b-iv, c-i, d-ii
DS0259
Kwashiorkor disease is due to :-
Which of the following gastric cells indirectly help
(1) Simultaneous deficiency of proteins and fats
in erythropoiesis ?
(2) Simultaneous deficiency of proteins and calories
(1) Chief cells
(2) Mucous cells
(3) Deficiency of carbohydrates
(3) Goblet cells
(4) Parietal cells
(4) Protein deficiency not accompained by calorie
deficiency
DS0260
DS0166
ANSWER KEY
EXERCISE-II (Previous Year Questions)
Que.
Ans.
Que.
Ans.
47
1
3
2
4
3
1
4
4
5
3
16
4
17
2
18
3
19
4
20
4
6
3
7
2
8
2
9
4
10
1
11
1
12
3
13
3
14
2
15
2
ALLEN
Pre-Medical : Biology
Master Your Understanding
EXERCISE-III (Analytical Questions)
EXERCISE-III(A) (NCERT BASED QUESTIONS)
1.
6.
Select the correct statements.
(a) Salivary glands situated just outside the buccal
cavity.
(b) Liver is the largest digestive gland.
(c) Hepatic duct not arises from gall bladder.
(d) Sphincter of Oddi can regulate the released of
pancreatic and bile juice in duodenum.
(1) a, b, c & d
(2) a, b & d
(3) b, c & d
(4) a, b & c
DS0177
7.
The process of digestion is accomplished by :(1) Mechanical process
(2) Chemical process
(3) Electrical process
(4) Both 1 & 2
DS0178
8.
Which of the following helps in lubricating and
adhering the masticated food particles into a bolus.
(1) Salivary amylase
(2) Mucous
(3) Secretion of lachrymal gland
(4) Gastric juice
DS0179
Select the incorrect statements :(a) alimentary canal begins with an anterior cavity
called buccal cavity.
(b) tooth is embedded in a socket of mandible bone
only.
(c) human shows strict diphyodont type of dentition.
(d) oesophagus and the trachea open into the
pharynx.
(1) a, b, c & d
(2) a, b & c
(3) a, c & d
(4) a, b & d
DS0172
2.
The oesophagus is a thin, long tube which extends
_____ passing through the neck.
(1) anteriorly
(3) horizontally
(4) obliquely
21
(2) posteriorly
In human __________ is a small blind sac, which
(2) Colon
(3) Rumen
(4) All of these
n
(1) Caecum
:2
hosts some symbiotic micro-organism.
ss
io
DS0174
9.
Which of the following electrolytes is/are present
in saliva of human?
(1) Na+
(2) K+
(3) Cl–
(4) above all
DS0180
10.
Select the correct statements.
Select the correct structural sequence of alimentary
Se
4.
02
3.
0-
DS0173
canal facing from inside to outside.
(1) Serosa ® Muscularis ® Submucosa ® Mucosa
(2) Muscularis® Serosa ® Mucosa ® Submucosa
(3) Mucosa® Submucosa ® Muscularis ® Serosa
(4) Submucosa ® Mucosa ® Muscularis ® Serosa
Chymotrypsin
(1) Trypsinogen ¾¾¾¾¾
® Trypsin
DS0175
5.
Pepsin
(2) Procarboxypeptidase ¾¾¾¾
® carboxypeptidase
All of the following are correct with respect to
Ptylin
(3) Proamylase ¾¾¾
® Amylase
intestine of human except.
(1) Colon having ascending, descending and
HCl
(4) Pepsinogen ¾¾¾
® Pepsin
transverse part.
DS0181
(2) Duodenum is C-shaped structure
(3) Taeneae & haustra is present all along the length
of intestine.
(4) Highly developed villi is restricted to small
intestine.
DS0176
11.
Select the odd with respect to enzymes present in
adult human.
(1) Rennin
(2) Renin
(3) Trypsin
(4) Pepsin
DS0182
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48
E
ALLEN
12.
Pre-Medical : Biology
Which of the following is not produced by the brush
16.
49
Find out the correct match from the following table :-
border cells of the intestinal mucosa.
(1) dipeptidases
Column-I
(2) nucleosidases
(2) lipases
Column-II Column-III
A Goblet cells Mucus
Prevent
mucosa layer
from damage
of HCl
B
Lysozyme
Saliva
Antibacterial
agent
C
Saliva
Subparotid
gland
Secrete
salivary
amylase
HCl
Stimulate
gastric lipase
(4) steapsin
DS0183
13.
All of the following is correct w.r.t. large intestine
except.
(1) No significant digestive activity.
(2) Absorption of some water
(3) Absorption of certain minerals.
D Oxyntic
cells
(4) Absorption of remaining glucose and amino acid.
DS0184
14.
In which of the following disease liver is affected,
skin and eyes turn yellow due to the deposition of
(1) Only 'A'
(2) A and B
(3) Only C
(4) C and D
DS0187
(1) Vomiting
17.
02
regarding digestion and absorption of food in
(3) Diarrhoea
human beings :-
:2
(4) Dysentry
io
n
DS0185
ss
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Coloum I
amylase in our oral cavity
proenzyme trypsinogen
Se
Match the following :
(a) About 90% of starch is hydrolysed by salivary
(b) Entero-endocrine cells in our stomach secrete the
EXERCISE-III(B) (ANALYTICAL QUESTIONS)
15.
Which of the following statements is/are incorrect
0-
(2) Jaundice
21
bile pigments.
(c) Vitamin-D is produced in human body in skin
(d) Bile salts act as activator of pancreatic lipase
Coloum II
(1) Two, a and b
(A) Salivary gland (i) Trypsinogen
(2) Two, a and c
(B) Stomach
(ii) Bile pigments
(3) Two, a and d
(C) Pancreas
(iii) Saliva
(4) Three, a, b and d
(D) Intestine
(iv) Erepsin
(E) Gall bladder
(v) Gastric juice
DS0188
18.
Largest internal organ of the body is :(1) Skin
(1) A-v, B-iii, C-i, D-ii, E-iv
(2) Liver
(2) A-iii, B-v, C-i, D-iv, E-ii
(3) Pancreas
(3) A-iv, B-iii, C-ii, D-i, E-v
(4) Small intestine
(4) A-ii, B-v, C-i, D-ii, E-iv
DS0186
DS0189
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Pre-Medical : Biology
50
19.
Identify A, B, C and D and choose correct option
regarding their number in upper jaw :-
22.
Conversion of large fat globules into smaller globule
is :-
A
B
C
(1) Emulsification
(2) Digestion
(3) Assimilation
(4) Specification
DS0193
23.
D
Micelle formation occurs in :(1) Enterocyte
(2) Duodenum
A
B
D
(1)
Incisor-2
Canine-2
Premolar-2 Molar-3
(2)
Incisor-4
Canine-4
Premolar-8 Molar-12
(3)
Incisor-4
Canine-2
Premolar-4 Molar-6
(4)
Incisor-2
Canine-1
Premolar-2 Molar-3
(3) Lacteals
(4) Pancreas
DS0194
24.
Chymotrypsinogen is produced by
(1) Liver
(2) Pancreas
(3) Stomach
(4) Duodenum
DS0195
DS0190
Identify the correct match from the column I, II
and III.
(2) gastrin
Column-III
Salivary
gland
a
Lacteal
i
Emulsification
of fat
B
Villi
b Goblet cells
ii
One pair
C
Intestinal
epithelium
c
Bile juice
iii
Absorption of
fat
D
Liver
d
Sub maxillary
gland
iv
Mucous
(4) none of these
26.
DS0196
n
io
Read the following statements (A-D)
(A) The stomach stores the food for 4-5 hours
(B) The food mixes throughly with the acidic
intestinal juice
(C) Trypsinogen is activated by an enzymeenterogastrone, secreted by the intestinal
mucosa
(D) Renin is enzyme found in gastric juice of infants
which helps in digestion of milk protein
How many of the above statements are wrong ?
(1) Four
(2) One
(3) Two
(4) Three
DS0192
because :
(1) Liver stores excess of protein
(3) Liver stores excess of starch
ss
DS0191
A person addict for alcohol gets his liver destroyed
(2) Liver stores excess of fat
(4) Liver stores excess of glycogen
Se
(1) A-d-i, B-a-iii, C-b-iv, D-c-ii
(2) A-d-ii, B-a-iii, C-b-iv, D-c-i
(3) A-a-ii, B-d-iv, C-b-iii, D-c-i
(4) A-b-i, B-a-ii, C-c-iii, D-d-iv
(3) cholecystokinin
0-
A
21.
(1) citric acid + acetyl Co-A
21
Column-II
Contraction of gall bladder is carried by :
02
Column-I
25.
:2
20.
DS0197
27.
Anti-sterility vitamin is :
(1) Vitamin B12
(2) Vitamin D
(3) Vitamin E
(4) Vitamin A
DS0198
28.
The longitudinal muscular folds of inner wall of
stomach are called :
(1) Papilla of vater
(2) Rugae
(3) Villi
(4) Fissure
DS0199
29.
Gastric rugae are found in
(1) Kidney
(2) Liver
(3) Nephron
(4) Stomach
DS0200
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30.
Pre-Medical : Biology
Trypsinogen is :
39.
Which of the following vitamins are fat soluble?
(1) A, B, C, K
(2) A, B, D, E
(3) A, D, E, K
(4) A, D, C, K
DS0210
40.
The organ in human body where Brunner's glands
are present ?
(1) Large intestine
(2) Small intestine
(3) Liver
(4) Kidney
DS0211
41.
'Crypts of Lieberkuhn' are found in :
(1) gall bladder
(2) liver
(3) pancreas
(4) intestinal wall
(1) Hormone secreted by mucosa
(2) Enzyme secreted by mucosa
(3) Inactive enzyme secreted by pancreas
(4) Secreted by endocrine gland related to digestion
DS0201
31.
32.
33.
Part of bile juice useful in digestion is :
(1) Bile salt
(2) Bile pigment
(3) Bile matrix
(4) All of them
DS0202
From which of the following pepsin is secreted :
(1) Lungs
(2) Stomach
(3) Salivary gland
(4) Sebaceous gland
DS0203
Secretin hormone stimulates :
(1) Gastric glands
(2) Pancreas
(3) Gall bladder
(4) Crypts of Lieberkuhn
DS0212
42.
43.
21
Fint out the correctly matched pair :
(1) Pepsinogen ® Zymogenic cells
(2) HCl ® Goblet cells
(3) Mucus ® Oxyntic cells
(4) Pancreatic juice ® Salivary glands
0-
35.
n
io
Castle interinsic factor helps in absorption of
(1) Vitamin - B12
(2) Vitamin - B6
(3) Vitamin - A
(4) Vitamin - C
DS0216
45.
Pancreatic juice contain bicarbonate which is
secreted by :
(1) paneth cells
(2) goblet cell
(3) kupffer's cell
(4) aciner cell
DS0217
46.
Identify the false statement :
(1) oesophagus does not secrete any enzyme
(2) gall bladder concentrate bile juice
(3) human teeth are thecodont
(4) there are two pairs of salivary glands in humans
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
Se
ss
44.
E
DS0206
38.
Among mammals, a significant role in the digestion
of milk is played by :
(1) Rennin
(2) Invertase
(3) Amylase
(4) Intestinal bacteria
DS0207
pH of gastric juice is :
(1) 2
(2) 4
(3) 6
(4) 8
DS0208
Which of the following hormone helps in secretion
of HCl from stomach ?
(1) renin
(2) gastrin
(3) secretin
(4) somatostatin
DS0209
The main digestive function of enterokinase is :
(1) conversion of pepsinogen into pepsin
(2) conversion of trypsinogen into trypsin
(3) conversion of trypsin into trypsinogen
(4) stimulation of the gastric glands to secrete gastric
juice
DS0214
02
Prorennin is secreted by :
(1) zymogen cells
(2) sertoli cells
(3) Islets of langerhans
(4) hepatacytes
DS0205
:2
34.
37.
Glisson's capsule is asociated with :
(1) liver
(2) pancreas
(3) lungs
(4) kidney
DS0213
DS0204
36.
51
DS0218
47.
Pepsinogen is activated by
(1) Castle intrinsic factor (2) HCl
(3) Bile juice
(4) Enterokinase
DS0219
Column I
Column II
A. Hepatic lobule
i. Submucosal glands
B. Brunner's glands
ii. Base of villi
C. Crypts of lieberkuhn
iiii. Glisson's capsule
D. Sphincter of Oddi
iv. Gall bladder
E. Cystic duct
v. Hepatopancreatic duct
vi. Serous glands
D
E
v
iv
vi
i
v
iv
ii
i
DS0220
(1)
(2)
(3)
(4)
A
iii
v
iii
iv
B
vi
ii
i
vi
C
ii
iii
ii
v
Which an organ is affected in jaundice ?
(1) Stomach
(2) Pancreas
(3) Liver
(4) Parotid glands
DS0221
50.
Secretin and cholecystokinin are digestive
hormones. They are secreted by :
(1) Oesophagus
(2) Ileum
(3) Duodenum
(4) Pyloric stomach
DS0222
Kwashiorkar disease is due to deficiency of :
(1) protein
(2) fat
(3) sugar
(4) hormone
DS0226
55.
Carbohydrate digestion occurs first in which
structure?
(1) mouth
(2) intestine
(3) stomach
(4) none of these
DS0227
56.
Enzyme pepsin acts in :
(1) acidic medium in the pancreas
(2) acidic medium in the stomach
(3) intestine
(4) mouth
DS0228
57.
Bile secretion is proportional to the concentration
of :
(1) protein
(2) fat
(3) carbohydrate
(4) none of these
DS0229
58.
Digestive enzymes are :
(1) hydrolase
(3) transferase
Protein deficiency leads to :
(1) Kwashiorkar
(2) Marasmus
(3) Cretinism
(4) both (1) and (2)
DS0231
60.
Pepsinogen is secreted by :
(1) chief-cells
(2) oxyntic cells
(3) mast cells
(4) parietal cells
DS0232
61.
In mammals the teeth are
(a) of different types
(b) embedded in the cuplike socket in the jaw bones
(c) two sets present throughout life
The condition are referred as :
(1) heterodont, thecodont, diphyodont
(2) thecodont, heterodont, diphyodont
(3) diphyodont, thecodont, heterodont
(4) heterodont, diphyodont, thecodont
DS0233
Se
(1) bile is secreted by liver
(2) stomach is divided into two parts
(3) parietal cell lie in wall of stomach
(4) liver is the largest gland of human body
DS0223
52.
Which part of body secretes the hormone secretin?
(1) stomach
(2) oesophagus
(3) illeum
(4) duodenum
DS0224
53.
Which one is correct about the "rennin" ?
(1) It helps in digestion of milk-sugar.
(2) It is found in gastric juice of adult human.
(3) It is proteolytic enzyme found in saliva.
(4) It is found in gastric juice of infants.
DS0225
(2) oxido-reductase
(4) none of these
DS0230
59.
io
Identify the false statement ?
ss
51.
n
:2
49.
54.
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
Find out the correct match :
21
48.
ALLEN
0-
Pre-Medical : Biology
02
52
E
ALLEN
53
Which of the following process will be affected by
the absence of enterokinase?
(1) Lipid ® Fatty acid + glycerol
(2) Dipeptides ® Amino acid
(3) Proteoses ® Dipeptide
(4) Amylose ® Maltose
DS0234
Z:\NODE02\B0B0-BA\TARGET\BIO\ENG\MODULE_7\03-DIGESTION AND ABSORPTION_EXE.P65
Se
ss
io
n
:2
02
0-
21
62.
Pre-Medical : Biology
E
EXERCISE-III (Analytical Questions)
Que.
Ans.
Que.
Ans.
Que.
Ans.
Que.
Ans.
Que.
Ans.
ANSWER KEY
1
2
2
2
3
1
4
3
5
3
6
1
7
4
8
2
9
4
10
4
11
1
12
4
13
4
14
2
15
2
16
2
17
1
18
2
19
3
20
2
21
4
22
1
23
2
24
2
25
3
26
2
27
3
28
2
29
4
30
3
31
1
32
2
33
2
34
1
35
1
36
1
37
1
38
2
39
3
40
2
41
4
42
1
43
2
44
1
45
4
46
4
47
2
48
3
49
3
50
3
51
2
52
4
53
4
54
1
55
1
56
2
57
2
58
1
59
4
60
1
61
1
62
3
ss
io
n
:2
02
021
Pre-Medical : Biology
E
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IMPORTANT NOTES