From Mouth to Anus - Sun Prairie High School
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Transcript From Mouth to Anus - Sun Prairie High School
From Mouth to Anus
The Digestive System
Challenges
Food Presents all animals with at least two
challenges:
1.
2.
How to obtain it?
How to break food down into small molecules that
can be passed to cells that need them?
Function
To help convert foods into simple molecules
that can be absorbed and used by the cells of the
body.
The digestive system is built around an alimentary
canal a one-way tube that passes through the
body.
This is also known as the Gastro Intestinal Tract (G.I.
Tract)
Anatomy and Physiology of the G.I. Tract
Mouth (oral cavity): place where food enters;
mechanical and chemical digestion begins
Tongue: moves food around, pushes it to back
of the mouth for swallowing, clump of food is
then called a bolus.
Teeth (mechanical): breaks down food into
smaller particles to increase surface area for
chemical digestion
A & P of G.I. Tract
Salivary Glands (chemical): secretes saliva, which
contains an enzyme called amylase. Salivary
amylase breaks down starch into disaccharides.
A & P of the G. I. Tract
Esophagus: muscular tube that connects the
mouth to the stomach
Peristalsis: wave-like motion that pushes food
down
A & P of G.I. Tract
Stomach:
HCl and pepsin break
down proteins.
Lined with mucus so that
it doesn’t digest itself
Stomach muscles
contract to mix food into
chyme.
Food stays here 2-4
hours
A & P of G.I. Tract
Small Intestine: approx. 6 meters long
Made of three sections: duodenum, jejunum,
ileum
Most important digestive organ, as digestion of
carbs, fats, and proteins is completed here.
Also the site of nutrient absorption (villi and
capillaries)
A & P of G.I. Tract
Large intestine a.k.a. “COLON”
Approx. 1.5 meters long
Site of water absorption
Leaves behind solid material called feces
Food stays here 18-24 hours
Not enough water absorbed= diarrhea
Too much water absorbed= constipation
A & P of G.I. Tract
Rectum: stores solid waste until appropriate
time for removal
Anus: solid waste exits through this opening
Entire journey takes approx. 24-33 hours
ACCESSORY TO DIGESTION
These structures are
NOT a part of the G.I.
Tract, food does NOT
travel here!
LIVER: produces bile,
which helps break down
fats
GALLBLADDER:
stores bile
Accessory to Digestion
CBD: common bile duct,
transfers digestive juices
from liver, pancreas, and
gallbladder to the small
intestine
Pancreas: secretes fluid
to help breakdown fats,
carb’s, and proteins in
the small intestine.
Digestive System Anatomy
Quiz
1. Where does digestion
begin?
2. What is the name of
the tube that connects
the mouth to the
stomach?
3. What enzyme does
your salivary glands
secrete?
4. What is the name of
the wave-like motion
that pushes food
throughout the G.I.
Tract?
5. In which organ does
nutrient absorption take
place?
6. In which organ does
water absorption take
place?
QUIZ
7. Trace the pathway a
hamburger will travel,
from the mouth to the
anus. Hint: You should
include 7 structures.
8. What is the function
of the liver?
9. In which organ do the
digestive juices work in?
10. What organic
compound does your
stomach start breaking
down?
11. Where are
carbohydrates broken
down? Careful!
12. How do nutrients
get from the small
intestine to the
bloodstream?
ANSWERS
1. Mouth
2. Esophagus
3. Amylase
4. Peristalsis
5. Small intestine
6. Large intestine
7. Mouth esophagus
stomach s.intestine
l.intestinerectum
anus
8. Produce bile
9. Small intestine
10. Proteins
11. Mouth and small
intestine
12. Villi, capillaries