Download The Digestive System

The Digestive System
Period 3, Haas (Q2 2011)
Bo Dunham, Kelsey Williams,
Hanna Shokouhi, Kyle Love
Digestive System
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Mouth
Esophagus
Stomach
Small Intestine
Liver
Gallbladder
Pancreas
Large Intestine
Colon
Rectum
Anus
Mouth
• Mechanical Digestion:
Chewing food and
breaking it into smaller
pieces
• Chemical Digestion:
Begins with amylase in
saliva released by
salivary glands
• Amylase: begins to
break down starches
(polysaccharides to
monosaccharides)
Esophagus
• After swallowing,
moves food from the
mouth to the stomach
• Rhythmic contractions
of muscles along sides
to push food to
stomach (peristalsis)
Stomach
• Food mixes to make chyme
• Chyme is a mixture of the partially
broken down food and chemicals
• Chemical digestion begins in the
stomach with the HCl (hydrochloric
acid) and other chemicals
• Another chemical that breaks down
proteins is pepsin which is the active
form of pepsinogen. It becomes
active in the presence of HCl
• The stomach is protected from the
HCl by the mucous membrane.
When that fails to be made properly,
such as during chemotherapy, the
HCl begins to break down the
stomach lining and causes ulcers
Small Intestine
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Chyme enters the small intestine
(beginning is the duodenum)
from the stomach through the
pyloric valve
Where the most nutrient
absorbtion occurs
Enzymes help with absorbtion
that come from the parcreas
(sodium bicarbonate) and liver
(bile)
When chyme enters the small
intestine the carbs and proteins
are only partially digested,
digestion finishes here
Villi (singular- villus) are small
folds in the lining of the small
intestine that increase the
surface area to absorb more
nutrients
Liver
• Secreates bile (not an
enzyme)
• Bile is stored in the
gallbladder until it is inserted
into the small intestine to help
with digestion. Helps break
down fat by emulsifying it and
not letting it congeal
• Emulsify: to break into
smaller pieces
• Molecules of bile are
amphipathic so they stick to
the fat on one side and repel
from each other, breaking the
fat apart
Emulsification
Web Resources
• http://www.5min.com/Video/Learn-howthe-Digestive-System-Works-117554716
• http://www.5min.com/Video/Ways-to-HelpYour-Digestive-System-93890102
• http://www.5min.com/Video/Learn-aboutthe-Digestive-System-117551302
• http://vimeo.com/15992520
Pancreas
• Located behind the stomach
• Secreates sodium
bicarbonate (not an enzyme)
which it releases into the
small intestine to help
digestion
• Sodium bicarbonate: liquid
chalk
• Very basic solution (as
compared to acidic chyme)
so helps to neutralize the
environment in the small
intestine
Large Intestine
• After the small intestine the
indigestible material enters here
• The main function of the large
intestine is to reabsorb the water
from the indigestible material
• Amount of water left in indigestible
material determines consistency of
excretion
• Some bacteria also located here
that helps break down indigestible
carbohydrates (lactase) and
synthesize vitamin B and K
complexes
Colon, Rectum, Anus
• Colon: The last few inches of the large
intestine
• Rectum: Where the indigestible material is
collected before it is released.
• Anus: Last opening through which
indigestible material is expelled
Practice Questions
1.
What type of break down occurs in the mouth?
A.
Mechanical
B. chemical
C. Both
2. What enzyme is released by your salivary glands?
A.
Bile
B. HCl
C. Amylase
3. What connects the mouth to the stomach?
A.
The large intestine B. the liver
C.
The esophagus
4. What is the contraction of the smooth muscles in the esophagus?
A.
Hector B. peligalus C. peristalsis D. Bo
5. What is the large muscle sack that the esophagus connects to?
A.
Liver B. Gallbladder C. Stomach
Practice Questions
6. What makes the stomach acidic?
A.
H2O B. Cl C. HCl
7. What is released into the stomach that speeds up digestion?
A.
Pepsinagen B. Pepsi C. Pepsin
8. Pepsin breaks ______ into small peptide fragments.
A.
Fats B. Carbs C. Protein
9. What type of digestion takes place in the stomach?
A.
Chemical B. Mechanical C. Both
10. Chyme is _______?
A.
Secreted by the pancreas B. produced by the liver C. made in the
stomach
Practice Questions
11. From the stomach, your food goes to the ____?
A. Liver B. large intestine C. small intestine
12. Most of the digestions occurs in the _____?
A. Stomach B. large intestine C. small intestine
13. Where is the pancreas located?
A. The brain B. left pinky toe C. behind the stomach
14. What does that pancreas make that neutralizes
stomach acid?
A. HCl B. bile C. Sodium Bicarbonate
15. The small intestine has circular folds that contain
_____.
A. Sodium B. HCl C. villi
Practice Questions
16. The _____ is after the small intestine.
A. Rectum B. stomach C. large intestine
17. The large intestine does ____.
A. Absorb bile B. take HCl from waste C. removes the
water
18. The large intestine produces ______.
A. HCl B. bile C. Vitamin B and K
19. Stuff exits the body through the ____.
A. Mouth B. stomach C. anus
20. The coolest student in Mr. Haas’s class is?
A. Kelsey B. Bo C. Alana and Bridget D. Love
Key
C