Download Ch. 38-2 Digestive System notes only

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Vocabulary
Digestive
System
Ch. 38-2
I. Anatomy and Function
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
esophagus
peristalsis
stomach
small intestine
pancreas
liver
villus
large intestine
9.  amylase
10. pepsin
11. chyme
12. gall bladder
13. bile
II. The Alimentary Canal
A.  Functions
1.  Convert food into smaller
molecules that can be
absorbed by cells
2.  Remove solid waste
B.  2 Major components
1.  the Alimentary Canal (your food
tube)
2.  Digestive glands
How does digestion relate to cellular
respiration?
A.  Mouth – 2 types of digestion
1.  Mechanical digestion – tear &
crush food (chewing)
2.  Chemical digestion
a.  saliva = produced by salivary
glands, moisten food making it
easier to chew
b.  Contains amylase (breaks down
carbs) and lysozyme (kills
bacteria)
DRAW Figure 38-10 pg 979
C.  Esophagus
1.  Moves food to the
B. Pharynx (throat)
1.  Connects mouth to esophagus
2.  Swallow chewed up food ball called a bolus
3.  Epiglottis covers the trachea Why?
stomach by
peristalsis (wave-like
contractions to move
food to stomach)
2.  Lined with mucus
3.  No digestion occurs
D.  Cardiac Sphincter
1.  Thick ring of muscle that
Epiglottis
closes the esophagus
after food enters the
stomach.
  Why is this important?
2.  Heartburn (acid reflux) __________
  What causes it?
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3.  HCl kills bacteria and activates
E.  Stomach
pepsin
1.  Food moves through in 2-4 hours
a.  Pepsin breaks down large
2.  Food mixes with hydrochloric acid
protein molecules into small
chains of __________
(HCl) and pepsin to form chyme
(semi-digested food that leaves the
stomach).
 
What protects the stomach from
pepsin and HCl?
The Small Intestine
4.  After 1-2 hours, pyloric
valve opens and chyme
flows into the small intestine.
2.  Jejunum and Ileum
a.  inside of the intestine - not
F. Small Intestine - where most of
smooth, small folds called villi and
the villi have many microscopic
folds called microvilli
your food is digested and absorbed
(12-20 feet long)
1.  Duodenum
a.  Digestive enzymes from
the pancreas and the liver
are added to the food.
b.  The gall bladder adds bile
(a green-ish fluid that
breaks down lipids)
c.  The pancreas adds
sodium bicarbonate to…
WHY?
 
 
Why all of the folds?
Once absorbed, how do nutrients get
to cells?
Villi
Microvilli!
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G. 
Large Intestine (Colon)
Alimentary Canal
(Gastrointestinal GI Tract)
1.  Reabsorbs water from
undigested material
What happens when too much
water is absorbed? Too little?
2.  Bacteria in colon produce
Vitamin K and live off
undigested organic material
(e.g. E. coli)
3.  Bacteria generate gases
(methane and hydrogen
sulfide) as a by-product of
their metabolism 
H. 
Remaining undigested material
(feces) is excreted through the
rectum and anus
Accessory Organs
1. Mouth
2. Pharynx
3. Esophagus
4. Stomach
6. Large Intestine
5. Small Intestine
7. Rectum
III. Digestive Glands
A. 
Liver
1.  Detoxifies the blood
2.  Stores vitamins and minerals
3.  Converts foodstuffs from one form
8. Salivary
Glands
10. Liver
to another
4.  Produces bile
9. Pancreas (behind stomach)
11. Gall Bladder
B.  Gall Bladder
1. Stores and releases bile
2. Bile breaks down fats
C.  Pancreas
1.  Produces _______ and ________
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