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The Digestive System
Chapter 15
15.1
Functions: mechanical and
chemical breakdown of food
*absorption of nutrients
Consists of alimentary canal
and accessory organs
Wall of the Alimentary Canal
15.2 Characteristics of the Canal
1. Mucosa - protects tissues and carries absorption
2. Submucosa - glands, blood vessels, nerves
3. Muscular Layer - smooth muscle tissue, circular &
longitudinal fibers, pushes food (PERISTALSIS)
4. Serosa (serous layer) - visceral perioneum, outer covering
of the tube, lubricates surfaces (serous fluid)
Mixing Movements
Contractions mix food with digestive juices
Peristalsis - pushes food down the tube
Anatomy of the Mouth
Anatomy of a Tooth
Teeth
Incisors
Cuspid (canine)
Bicuspids
Molars
Tooth Decay
METH
MOUTH
ROOT CANAL
Salivary Glands
Parotid - ear, cheek
Submandibular - below jaw
Sublingual - under tongue
Pharynx
nasopharynx
oropharynx
laryngopharynx
Esophagus
esophageal hiatus is
where it penetrates the
diaphragm
cardiac sphincter at
entrance to stomach
STOMACH MUSCLES: Longitudinal, Circular,
Oblique
Stomach
Regions
• Cardiac
• Fundic
• Body (greater and
lesser curvature)
• Pyloric
Stomach Lining
Gastric Juices contain acids that break down
food - secreted by gastric glands
PEPSIN - most important digestive enzyme for
breaking down food
Mucus prevents stomach
from digesting itself
Chyme - paste, after food has been broken
down, released then into the duodenum via the
pyloric sphincter valve
Rugae - folds within
stomach
Gastric Pits contain
glands to make
juices
PANCREAS - secretes insulin which
breaks down sugars
Pancreatic Juice also breaks down fat
Liver
1 large right lobe | 1 smaller left lobe
Liver - ducts and vessels
Hepatic duct --> to common bile duct
Hepatic portal vein - circulates blood throughout
liver
Liver Functions
1.
2.
3.
4.
5.
6.
7.
blood glucose levels
breakdown of lipids and fats
protein metabolism
stores vitamins
destroys damaged RBCs
removes toxins
secretes bile
Remember 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.
Gall Bladder - under liver
cystic duct --> common bile duct
stores bile, digests fat
*gallstones may form
Small Intestine
Starts at the pyloric
sphincter
1. Duodenum
2. Jejunum
3. Ileum
Greater Omentum
a "curtain-like" membrane that covers the
intestines, stores fat and lays like a drape
Greater Omentum
Intestinal villi - increase surface area to
absorb nutrients, connect to vessels
The main function
of the small
intestine is to
secrete chemicals
that break down
food and carry the
nutrients away in
the blood
stream. In one
word:
ABSORPTION
Large Intestine
Cecum
Appendix
Colon (4 parts)
Cecum
Ascending
Transverse
Descending
Sigmoid
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...
How to Make Fake Poop...
LABEL THIS!
1. esophagus
2. liver
3. stomach
4. pyloric sphincter
5. duodenum
6. pancreas
7. jejunum
8. ileum
9. cecum
10. appendix
11. ascending colon
12. descending colon
13. sigmoid colong
14. anus
Nutrition
Disorders of the Digestive System
GERD
Gastroesophageal
reflux disease
Dysentery or Diarrhea
HEPATITIS A, B, C
Hepatitis A Vaccine
Who should get this vaccine?
Many people are recommended to receive hepatitis A
vaccine, including people at increased risk for exposure to
hepatitis A virus infection and people who are more likely to
get seriously ill if infected with the virus
Hepatitis A is caused by eating food and drinking water
infected with a virus called HAV. While it can cause swelling
and inflammation in the liver, it doesn't lead to chronic, or life
long, disease. Almost everyone who gets hepatitis A has a full
recovery, but may need hospitization
Hepatitis B is caused by the virus HBV. It is spread by contact
with an infected person's blood, semen, or other body fluid.
And, it is a sexually transmitted disease (STD).
Information on Hepatitis B
Some people never develop symptoms, others develop chronic
symptoms that stay with them their whole life.
Hepatitis C is caused by the virus HCV. It is spread the same
way as hepatitis B, through contact with an infected person's
blood, semen, or body fluid (see above).
Like hepatitis B, hepatitis C causes swelling of the liver and
can cause liver damage that can lead to cancer. Most people
who have hepatitis C develop a chronic infection. This may
lead to a scarring of the liver, called cirrhosis.
Blood banks test all
donated blood for
hepatitis C, greatly
reducing the risk for
getting the virus from
blood transfusions or
blood products.
Crohn’s Disease
IBS - Irritable Bowel Syndrome
STOMACH ULCERS
Lactose
Intolerance
Inability to digest
milk, can cause
stomach upset
Appendicitis
Hernia
intestines
poke through
abdominal
muscles
When people with celiac
disease eat foods or use
products containing gluten,
their immune system responds
by damaging or destroying villi
Without healthy villi, a person
becomes malnourished, no
matter how much food one
eats.
Gallstones (Cholelithiasis)
Gallstones are made from cholesterol and other
things found in the bile. They can be smaller than a
grain of sand or as large as a golf ball.
Gastric Bypass Surgery
http://www.hurtbyadoctor.c
om/Gastric-BypassSurgery-MalpracticeLawsuits-InformationHome.htm
Colon Cancer
Colonoscopy is a screening technique to detect cancer.
See Katie Couric's Colonoscopy