The Digestive System
Notes Packet
Essential Questions:
1. How do animals (and
humans) obtain nutrients?
What happens when animals
don’t get proper nutrients?
2. How is waste eliminated
from the body?
3. What disorders can affect
the working of the digestive
system?
A fistulated cow is a cow with a passageway (cannula) connecting
the cow’s rumen (stomach) to the outside. Researchers study how
a cow’s stomach works, the microflora in the cow’s stomach, and
how fast certain foods are digested.
What is scurvy?
A condition caused by a lack of
vitamin C.
A lack of vitamin C means that
collagen, a protein found in body
tissue such as skin and blood
vessels, cannot be replaced, leading
to tissue breakdown
Adult patients may suffer from
bleeding gums, swelling, slowhealing wounds, bruising.
Scurvy is a disease of malnutrition, often associated
with sailors who were at sea for long periods and had
no access to fresh fruits or vegetables.
Bleeding gums and tooth loss were some of the first
symptoms.
What is the function of the
digestive system?
- mechanical and chemical
breakdown of food and the
absorption of nutrients
-Consists of alimentary canal
and accessory organs
Characteristics of the Alimentary Canal
1. Mucosa - protects tissues and carries absorption
2. Sub-mucosa - glands, blood vessels, nerves
3. Muscular Layer - smooth muscle, pushes food
4. Serosa - lubricates surfaces
Draw this!
In the small
intestine...
Villi increase surface
area for absorption
of nutrients.
Celiac disease
damages the villi,
leaving your body
unable to absorb
nutrients necessary
for health and
growth.
Gluten in diet triggers immune cells to
attack the villi of the small intestine.
Mixing Movements
mix food with
digestive juices
Peristalsis - pushes
food down the tube
Anatomy of the Mouth - the first place of digestion
Mouth - begins digestion by chewing and mixing with saliva
Tongue - moves food, connects to floor of mouth via FRENULUM
Palate - forms roof of oral cavity (hard and soft); Uvula - back of the mouth
Palatine Tonsils - part of
the immune system
Tonsillitis is an
inflammation of the tonsils
and will often, but not
necessarily, cause a sore
throat and fever. In
chronic cases
tonsillectomy may be
indicated.
Teeth
INCISORS
Canines
Premolars
Molars
Salivary Glands
AMYLASE
- enzyme breaks down
starch into sugars
Mucus cells also
produce mucus for
lubrication during
swallowing
1.Parotid Gland
2. Submandibular Gland
3. Sublingual Gland
Pharynx
nasopharynx
oropharynx
laryngopharynx
STOMACH MUSCLES: Longitudinal, Circular, Oblique
Cardiac sphincter
ESOPHAGUS
FUNDUS
CARDIAC REGION
Longitudinal muscles
LESSER CURVATURE
PYLORIC SPHINCTER
Circular muscles
DUODENUM
Oblique muscles
BODY
RUGAE
of stomach
Stomach Lining
Mucus prevents stomach from
digesting itself
Rugae - wrinkles
within the lining
Pepsin - digestive enzyme for
breaking down food
Chyme - paste released then into
the duodenum
Acid reflux occurs when
stomach acid splashes back
into the esophagus, causing a
burning sensation (Heartburn.)
PANCREAS - secretes insulin which breaks down sugars
Pancreatic Juice also breaks down fat
Both empty
into the
DUODENUM
Liver - functions to create BILE
Liver Functions
1. Production of bile
2. Production of proteins
3. Storage of glycogen
4. Storage of vitamins
5. Blood clotting
6. Clears bilirubin
7. Detoxification
Bile – yellowish-green liquid aids
in digestion, breakdown of fat
The liver is an organ that
regenerate (regrow)
Bilirubin - produced when
blood cells break down.
Jaundice occurs when liver
fails to clear the bilirubin.
Causes yellowing of the skin
and eyes.
Treated with bili-lights.
Bili Lights
Using bili lights is a therapeutic procedure performed on newborn or
premature infants to reduce elevated levels of bilirubin. If blood levels of
bilirubin become too high, the bilirubin begins to dissolve in the body tissues,
producing the characteristic yellow eyes and skin of jaundice.
The Gallbladder
liver
- stores bile
- bile duct connects to
duodenum
- bile can form
gallstones
gallbladder
5 Day Old Pasta by
ChubbyEmu
https://www.youtube.com
/watch?v=5ujTYLV2Qo4
pancreas
duodenum
Gallbladder is removed if gallstones block ducts.
Small Intestine
Main function: absorption of nutrients
1. Duodenum
2. Jejunum
3. Ileum
MESENTERY - supports coils of
small intestine and contains
blood vessels
Greater Omentum (peritoneum)
membrane that covers the intestines, stores fat
Large Intestine
1. Cecum = start of large intestine,
has an attached appendix
- Ileocecal valve
(between sm. Intestine and cecum)
2. Colon = 4 sections,
ascending / transverse /
descending / sigmoid
3. Rectum – stores waste before it
is expelled from the body
4. Anus -muscular sphincter which
controls the exit of waste
Ileocecal valve
Stomach
Transverse Colon
Ascending Colon
Jejunum
Cecum
Appendix
Rectum
Descending
Colon
Ileum
Sigmoid Colon
The Appendix
Recent news on the function
of the appendix.
The appendix acts as a
storehouse for good bacteria,
“rebooting” the digestive
system after diarrheal
illnesses.
ScienceDaily Article
Appendicitis occurs when the structure
becomes infected or inflamed.
Function of Large Intestine
Secretes mucus, reabsorbs water, contains bacteria to aid in
digestion (intestinal flora)
Mass Movements (defecation) - removes undigested food
The main job is
WATER
REABSORPTION..
The Bristol Stool chart analyzes the
consistency of FECES.
*Feces is a fancy name for poop.
Disorders of the Digestive System
A Gastroenterologist is a physician with dedicated training and
unique experience in the management of diseases of the
gastrointestinal tract and liver.
Colonoscopy Test is used to
detect cancer in
the colon.
Dysentery or Diarrhea
Failure to reabsorb water in the large intestine,
which leads to watery stool. Dehydration can
lead to death.
Causes Include:
Parasitic Infection (Ameba, Cryptosporidium)
Bacterial Infection (Cholera, E. coli, Salmonella)
Viruses (Norovirus and other stomach bugs)
Food allergy or intolerance
Gastroenteritis is a generic name used
to describe vomiting and diarrhea
Cholera
Cholera bacteria
causes diarrhea,
leading to massive
loss of water that
can be fatal.
Bacteria is
transmitted through
unclean water
sources and
contaminated food.
The MICROBIOME
The average human digestive tract is
home to as many as 1,000 species of
microorganisms When something upsets
the balance of these organisms in your
gut, otherwise harmless bacteria can
grow out of control and make you sick.
One of the worst offenders is a bacterium
called Clostridium difficile(or C. diff).
Become a Stool Donor at OPENBIOME.org
HEPATITIS A, B, C
Hepatitis A -caused by eating food
or water infected with the virus
Hepatitis B & C - transmitted through
body fluid (STI)
Hepatitis B & C can lead to long term
(chronic) disease and even liver
failure.
Crampy abdominal pain
Loss of appetite
Bloody stool
Watery diarrhea
Weight loss
Constipation
IBS = Irritable bowel syndrome
STOMACH ULCERS
Burning upper
abdominal pain,
particularly between
meals, early in the
morning, or after
drinking orange juice,
coffee, or alcohol,
Treated with antibiotics
to kill H. pylori
bacteria.
Constipation
difficulty in emptying the bowels,
usually associated with hardened
feces.
symptoms of chronic constipation include:
● Passing fewer than three stools a week
● Having lumpy or hard stools
● Straining to have bowel movements
● Feeling as though you can't completely
empty the stool from your rectum
Hemorrhoids
swollen veins in your anus
and lower rectum
may result from straining
during bowel movements or
from the increased pressure
on these veins during
pregnancy
Can cause pain, itching, and
minor bleeding during bowel
movements
Lactose Intolerance
Inability to digest
milk, can cause
stomach upset
Hernia
intestines poke through
abdominal muscles
Malnutrition
lack of proper nutrition, caused by not
having enough to eat, not eating enough
of the right things, or being unable to use
the food that one does eat
- Scurvy (lack of vitamin C)
- Rickets (lack of vitamin D)
An essential nutrient is a nutrient required
for normal body functioning that can not be
synthesized by the body.
Most animals can synthesize their own
vitamin C, so they don’t need it in their diet.
Exceptions: primates, guinea pigs, fruit bats
*What do these animals have in common?
(2A)Assignment: Read “Broken Genes” by
Nathan Lents, Excerpt from Human Errors
Patient presents with bleeding gums and corkscrew shaped hairs
on legs. What is the diagnosis?
LABEL THIS!
esophagus
liver
gallbladder
stomach
pancreas
duodenum
transverse colon
ascending colon
descending colon
jejunum
ileum
cecum
appendix
anus
rectum
LABEL THIS!
Liver
Right Hepatic duct
Common Hepatic duct
Cystic duct
Common Bile duct
Gallbladder
Pancreatic duct
Pancreas
Duodenum