Small Intestines, Large Intestines and Anal Canal

Question 1

List the 3 sections of the small intestine. Which section is the shortest?

Answer 1

1. Duodenum: the first (and shortest section of the small intestine)
2. Jejunum
3. Ileum

Question 2

What are the names of the valves which are located at the beginning and end of the small intestine?

Answer 2

• Pyloric sphincter: runs from end of the stomach

- Ileocecal valve: at beginning of the large intestine

Question 3

List the names of the 3 specialized structures in the wall of the small intestine.

Answer 3

circular folds
villi
microvilli

Question 4

Where is bile formed and stored?

Answer 4

Bile is formed in the liver, and stored in the gallbladder.

Question 5

Describe in detail the 2 major functions of pancreatic juice.

Answer 5

• contains sodium bicarbonate, which neutralizes the chyme, and makes the pH of the small intestine slightly basic.
• contains digestive enzymes that further digest every major component of food.

Question 6

Describe how fats, sugars and amino acids are absorbed by the small intestine.

Answer 6

Each small intestinal villus contains blood vessels and a lacteal lymphatic vessel. Sugars and amino acids enter villi cells and then are absorbed into the bloodstream. Glycerol and fatty acids enter villi cells and are reassembled into fat molecules, which move into the lacteals.

Question 7

What are the 3 functions of the liver that are important in digestion?

Answer 7

The liver:

• produces Bile, which is then stored in the gallbladder before entering the small intestine, where it emulsifies fats.
• stores glucose as glycogen, and breaks down glycogen to glucose between meals to maintain a constant glucuse concentration (homeostasis) in the blood.
• produces UREA from amino groups that are removed from excess amino acids.

Question 8

List the 8 regions of the large intestine.

Answer 8

1. Cecum
2. Appendix
3. Ascending Colon
4. Transverse Colon
5. Descending Colon
6. Sigmoid Colon
7. Rectum
8. Anal Canal

Question 9

What are the 2 sphincters of the anal canal?

Answer 9

• INVOLUNTARY smooth muscle INTERNAL spinchter

- VOLUNTARY skeletal muscle EXTERNAL spinchter

Question 10

List the 4 functions of the large intestine.

Answer 10

• propels wastes
• reabsorbs water
• reabsorbs electrolytes
• absorbs Vitamin K and certain B vitamins produced by intestinal bacteria

Question 11

What are the 2 physiological problems caused by diarrhea?

Answer 11

• dehydration
• electrolyte loss

When materials pass through the colon too quickly, excess water is not reabsorbed, and diarrhea will result, which can lead to serious dehydration and electrolyte loss.

Question 12

List the content of feces.

Answer 12

75% water

25% solid matter containing: intestinal bacteria, undigested plant material, fats, bile pigments, inorganic material, mucus, and dead intestinal cells