Additional Study Material for Exam 3
Give any two characteristic features of thymus which are not present in a lymph node.
No sinus below capsule, parenchymal bridges, Hassall’s corpuscles
The lymph node receives lymph through what kind of vessels?
Afferent lymphatic vessels through capsule
The hilus of a lymph node contains what three vessels?
Efferent lymphatic vessels, arteries and veins
Spleen white pulp consists of:
lymphocytes and red pulp consists of venous blood
Spleen filters blood or lymph? And why?
Spleen filters blood but not lymph because it does not receive lymph from
anywhere – there no afferent lymphatic vessels.
What are the 4 major basic tissue layers in the wall of alimentary canal?
Mucosa, submucosa, muscularis externa, serosa
The epithelium in the mucous membrane of mouth is: stratified squamous
The V- shaped groove on the tongue is called: sulcus terminalis
The type III cells are believed to have: gustatory cells.
The mineral hydroxyapatite is present in: dentin, enamel and bone
The cells that produce dentin are: odontoblasts and
those that produce enamel are: ameloblasts
The kinds of secretions from mucous and serous acini of salivary glands respectively are:
viscous and water
The kind of epithelium in pharynx is:
stratified squamous epithelium in oral and laryngeal pharynx and stratified
ciliated columnar with goblet cells in the nasal pharynx
The surface epithelium in the esophagus is: stratified squamous
The 4 layers in the wall of esophagus are:
mucosa, submucosa, muscularis externa and adventitia
The surface epithelium in the stomach is: simple columnar
The gastric mucosa is thrown into large folds called: rugae
which in turn have smaller pits called: foveolae
The three kinds of glands in gastric mucosa are: cardiac, oxyntic and pyloric
Give the names and secretion(s) / function(s) of 5 kinds of cells in the gastric glands:
Mucous Neck Cells - Columnar, lodged between large rounded oxyntic cells,
Nucleus displaced in the base of the cell PAS+ secretory granules in
cytoplasm with mucigen
Stem Cells - Responsible for continuous renewal of gastric mucosa, Surface
mucous cells are replaced every four days
Oxyntic or Parietal Cells - Most conspicuous, pyramidal with large spherical
nucleus, produce HCl, have broad rounded bases and large mitochondria,
apical surface has invaginations called secretory canaliclui, microvilli
project into the lumen of secretory canaliculi, cytoplasm has no secretory
granules, active oxyntic cells have five fold increase in secretory
canaliculi and microvilli, 60-80 % of the increase is due to H+ / K+
ATPase for acid secretion, Oxyntic cells also produce gastric intrinsic
factor (GIF) for absorption of vitamin B 12, Deficiency of GIF results in
erythrocyte immaturity and Pernicious anemia, Deficiency of acid results
in achlorhydria
Chief or Zymogenic Cells - found in lower third of oxyntic glands, absent in
cardia, sparse in fundus and rare in pylorus, Numerous apical secretory
granules containing pepsinogen, Well developed Golgi complex, rough
ER and lysosomes,
Enteroendocrine cella - found scattered individually among the cells of all glands,
are called argentaffin or enterochromaffin cells, produce biogenic amines
and peptide hormones
• G cells – gastrin for gastric motility and acid secretion
• EC cells – secretin for gastric motility
• D cells – somatostatin – inhibits other enteroendocrine cells
• A cells – enteroglucagon – raises blood sugar level
• ECL cells – histamine for gastric secretions
The enzyme localized in the membranes of oxyntic cells is: H+ / K+ ATPase
What is the pH of the gastric secretions? 0.9 -2.0
The three specializations that increase surface area in small intestine are:
plicae circulares, villi and microvilli
What are the names and functions of the secretions from the following cells in small
intestine?
A or α cells in pancreas and stomach; produce glucagon for carbohydrate
metabolism
B or β cells in pancreas; produce insulin for carbohydrate metabolism
D or δ cells in pancreas, stomach and intestine; produce somatostatin which
inhibits secretion of glucagon and insulin
D1 cells in pancreas, stomach and intestine; produce vasoactive intestinal
polypeptide for vasoconstriction
EC cells in pancreas, stomach and intestine; produce serotonin for
vasoconstriction
ECL cells in fundic stomach; produce histamine for vasodilation
G cells in duodenum and pyloric stomach; produce gastrin for gastric secretions
I cells in jejunum and ileum; produce cholecystokinin which inhibits secretion of
gastric juices and stimulates pancreatic juices and bile ejection from
gallbladder
S cells in jejunum and ileum; produce secretin which inhibits secretion of gastric
juices and stimulates pancreatic juices
The kind of epithelium is small intestine is: simple columnar
What are kinds of cells / glands present in SI epithelium? And their functions?
Absorptive cells - Simple columnar with microvilli and surface coat made of
glycoproteins, Microvilli have actin and myosin that are responsive to
ATP and Ca++, Lateral walls of cells are widened for absorption of fat
and accumulation of chylomicra, Digestion occurs at the surface,
Disaccharides to monosaccharides by disaccharidases, Polypeptides to
amino acids by proteases
Goblet cells - Unicellular exocrine cells secreting PAS+ mucus
Enteroendocrine cells, Scattered at the base of epithelium, Also called
enterochromaffin or argentaffin cells, Secrete hormones into lamina
propria, Common in duodenum, fewer in jejunum – see above for all
details of enteroendocrine cells
Crypts of Lieberkuhn - Are intestinal glands at the base of the villi, Produce
watery intestinal juices which serve as solvent for digested nutrients
Paneth Cells - Are small group of cells at the base of crypts of Lieberkuhn,
Produce and release antibacterial lysozyme and phospholipase A2
What are lacteals and where are they located? What is their function?
lacteals are lymphatic capillaries in SI villi for absorption of lymph loaded with
ats.
The specific location for Peyer’s patches is: lamina propria of ileum
What are M cells? Cells that help capture microorganisms in Peyer’s patches
What is the function of Paneth cells? They produce antibacterial lysosomes and
phospholipase 2 - and where are they located? Bottome of crypts of Lieberkuhn
Give the specific location for the Brunner's glands: Submucosa of duodenum
Give the names of a protein digesting enzymes secreted from small intestine:
leucine amino peptidase
Give any 2 specific characteristic features of appendix that are not present in the rest of
the large intestine?
Cross section of appendix shows angular outline, Villi are absent in appendix but
crypts of Lieberkuhn are present
What change in epithelium occurs in rectum and anus? Becomes stratified squamous
The three nerve plexus that form deeper intrinsic system in the intestines are:
GI is innervated by divisions of autonomic nervous system - Parasympathetic,
sympathetic and enteric, Parasympathetic and sympathetic constitute extrinsic
division and enteric constitutes intrinsic division
The Intrinsic Division - Located within the walls, is autonomous and can work
without CNS - Superficial in subserous area
Deeper and most conspicuous
Myenteric (Auerbach’s) plexus between longitudinal and circular muscles,
Deep muscular plexus – mucosal aspect of circular muscles
Submucosal (Meissner’s) plexus
Give the special features of colon and cecum mucosa
Simple columnar epithelium, No plicae circulares, No villi beyond ileocecal
sphincter, Numerous crypts of Lieberkuhn, No Paneth cells, Abundant goblet
cells
Hepatic sinusoids are branches of: hepatic portal vein
What vessels are expected to be found in a portal canal – arteries, veins, lymphatic
vessels and bile ducts
The blood capillaries in the liver are called: sinusoids
A classical liver lobule is defined as: cells radiate around central veins
What kind of cells are found in sinusoidal lining?
endothelial and Kupffer
What is space of Disse and what is its function?
space between endothelium and hepatocytes, the function is formation of lymph
Give specific features of a hepatocyte - Cells are polyhedral (6 or more sides) with three
surfaces, One side is exposed to space of Disse, A second side is exposed to bile
canaliculi, A third one in contact with the adjacent cell, Large single nuclei, most cells
single nucleated; about 25 % are binucleate, One or more nucleoli per nucleus, rich in
rough ER, fat, glycogen, mitochondria and peroxisomes with enzymes uricase
The walls of bile canaliculi are rich in: ATPase activity
Order of bile duct branching is - Bile canaliculi  terminal ductules  (canals of
Hering)  drain into interlobular bile ducts  right and left hepatic ducts  common
bile duct after joining with cystic duct from gallbladder
Functions of liver include:
It filters and cleans blood – Kupffer cells involved
It is a blood storage site - sinusoids have enormous volume ~ 400 ml
Resistance to blood flow in liver causes development of ascites and leads to
cirrhosis
It processes and transfers nutrients
Maintains normal blood sugar level by glycogenesis and glycogenolysis
Maintains normal lipid levels by transporting or transforming
It is the site of synthesis of plasma proteins - Substantial rate of production of albumin,
alpha and beta globulins, glycoproteins, lipoproteins, prothrombin, fibrinogen etc.
It is the site of detoxication of lipid soluble drugs such as barbiturates (sleep inducers)
Enzymes in the smooth endoplasmic reticulum (microsomes) called microsomal
enzymes are responsible
Administration of drugs such as barbiturates stimulates activities of microsomal
enzymes
Has excretory function - Bilirubin from the breakdown of red blood cells is eliminated by
Kupffer cells, Bilirubin  urobilinogen  feces, Accumulation of bilirubin 
hyperbilirubinemia  jaundice, Causes of jaundice include increased production of
bilirubin, decreased uptake of blood by liver, disturbance in conjugation of bilirubin with
other substances and interference with its secretion
Major function of liver concerned with the digestive system is the secretion of bile
Bile consists of: Cholesterol, Lecithin, Fatty acids, Electrolytes, Bile salts, Bile salts
emulsify fat molecules
The function of bile is – emulcification of fats
The important histological features of gallbladder are:
Gallbladder wall consists of distinct
Mucosa – see below, Submucosa – dense connective tissue, Muscularis – all
smooth muscles, Subserosa – loose connective tissue, Serosa – loose
connective tissue
Epithelium is tall simple columnar with microvilli and is thrown into folds called
Rugae, Outpouchings called Rockitansky-Aschoff sinuses cross lamina propria and
muscles – this is a pathological condition, Lamina propria has loose connective
tissue with mucosal glands, Smooth muscles are longitudinal, transverse and
oblique, Frequently dense connective tissue with Luschka ducts are found among
smooth muscles, Luschka ducts are embryonic bile ducts which never established
connection with lumen – a histological feature
Junction of gallbladder with pancreas consists of A portion of duodenum wall,
The common bile duct, The pancreatic duct, The ampulla of Vater, The sphincter
of Oddi
Bile concentration by gallbladder is by which process?
Active transport of NA= followed by water by osmosis.
Describe the release and actions of small intestinal hormone for pancreatic stimulation
and secretion:
Hormonal stimuli are through the release of two hormones both from small intestinal
mucosa
Secretin – causes release of large volumes of bicarbonates solution to neutralize
acidic chyme
Cholecystokinin – causes release of large volumes of enzyme solution and
activates gallbladder for bile release
Pancreatic exocrine secretion contains
Pancreatic amylase for starch and glycogen digestion
Pancreatic lipase for digestion of lipids
Trypsinogen, chymotrypsinogen, procarboxypeptidases and trypsin inhibitor for
protein digestion
Also DNAse and RNAse
Pancreatic endocrine cells are located in – islets of Langerhans
Hormones from pancreatic endocrine cells and their secretions are
Alpha
Beta
Delta
cells
cells
cells
F
cells
Location
Periphery
Throughout
Throughout
Scattered
%/#
next to beta
70 %
third
least
Granules
large/dense
less dense
heterogeneous
-
Mitochondria
smaller
larger
-
-
Golgi
Complex
less
prominent
more
prominent
-
Hormones
glucagon
insulin
somatostatin
pancreatic
Polypeptide
Names of cartilages in larynx are
Three unpaired – thyroid, cricoid and epiglottis
Three paired – arytenoid, corniculate and cuneiform
Gradual changes that appear when trachea branches include
Cartilage ring to cartilage plates to complete disappearance
Epithelium columnar to low columnar or cuboidal to suamous in alveoli
Appearance of smooth muscles in bronchioles
What specific kinds of epithelium are found in the following locations?
Olfactory - pseudostratified columnar ciliated
Trachea – pseudostratfied columnar ciliated with goblet cells
Primary bronchi – ciliated columnar with goblet cells
Bronchiole – ciliated low columnar to cuboidal
Respiratory bronchioles – cuboidal to low cuboidal
Alveolar ducts – simple squamous
What are two chemical substances produced in type 2 alveolar cells?
Pulmonary surfactant consisting mainly of dipalmitoyl phosphatidyl-choline –
reduces surface tension of water
Also dense secretory granules called lamellar bodies rich in phospholipids
Also have alkaline phosphatase activity with clinical
What is the significance of Clara cells?
Are specialized cells which populate the epithelium of the respiratory tree from the
level of terminal bronchiole to alveolar duct.
Are polyhedral, non-ciliated with cytoplasmic biosynthetic organelles
Clara cells are known to have a role in:
• Surfactant production; their product is not the same as that produced by
the type II alveolar cells, but it may form one constituent of surfactant
• Detoxification; the number of Clara cells increases in response to
increased exposure to pollutants e.g. chronic cigarette inhalation
• Clara cells have secretory granules and produce guanylin for the control of
water an electrolyte transport in the GI
Barrier to diffusion of gases in alveoli consists of
• A layer of fluid surfactant
• A thin slender epithelium
• A basal lamina of the epithelium
• A thin interstitium
• A basal lamina of the capillaries
• A capillary endothelium
What are the kinds of pressure that help regulate breathing?
• Atmospheric Pressure – 760 mm Hg
• Intrapulmonary Pressure in the alveoli
• Intrapleural Pressure - 4 mm Hg lower than atmospheric pressure –
negative pressure is important for keeping lungs inflated
What are the muscles of inspiration? – diaphragm and external internalcostals
What are the muscles of expiration – for normal expiration just the relaxation of muscles
of inspiration is sufficient. For forced expiration the required muscles are abdominals and
internal intercostals.
Non-respiratory functions of respiratory system include
Metabolism - Monoamine oxidase and P450 microsomal enzymes
Endocrine function - Prostaglandin and histamine secretions
Speech - Vocal cords
Smell - Olfactory cells of nose