Transcript The Digestive System

The Digestive System
Chapter 14
Learning Goals
14.1 – Know the functions and major divisions of the
digestive system
14.2 – Identify the characteristics of the Alimentary
Canal
14.3 – Identify the organs of the digestive system and
draw the path of food through the Alimentary
Canal
14.4 – Describe the structure and function of the major
organs of the digestive system
LG 14.1
Functions:
1. Mechanical and chemical
breakdown of food
2. Absorption of nutrients
3. Elimination of wastes
Consists of:
1. alimentary canal
2. accessory organs
Wall of the Alimentary Canal
14.2 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 that pushes food along
4. Serosa (serous layer) - 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
Salivary
Glands
Parotid - ear, cheek
Submandibular - below jaw
Sublingual - under tongue
Pharynx
-Back of mouth
-Throat area
-Above the larynx
Esophagus
- Tube that food travels
from mouth to stomach
esophageal hiatus - is
where it penetrates the
diaphragm
cardiac sphincter thickened muscular ring
surrounding the opening
between the esophagus
and the stomach
STOMACH MUSCLES: Longitudinal, Circular,
Oblique
Stomach
- stores
just
recently swallowed
food.
-Mixes food
-Contain acids to
help break down
food
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 through 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
****Mesentery
- Membrane holds it
together, contains
blood vessels
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)
Ascending
Transverse
Descending
Sigmoid
Rectum
Anus
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...
transverse
colon
ascending
colon
stomach
descending
colon
cecum
appendix
rectum
sigmoid colon
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
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 disease. Almost everyone who gets
hepatitis A has a full recovery, some may need hospitalization
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 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).
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.
Crampy abdominal pain
Fatigue
Loss of appetite
Pain with passing stool
(tenesmus); bloody
stool
Persistent, watery
diarrhea
Weight loss
Constipation
IBS - Irritable Bowel Syndrome
The muscles in the
bowel wall may contract
too forcefully or too
weakly, too slowly or
rapidly at certain times.
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.
Gallstones within the gall bladder
Gastric Bypass Surgery
Colon Cancer
Colonoscopy is a screening technique to detect cancer.
See Katie Couric's Colonoscopy
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