Anatomy of Digestive System

Question 1

Which enzyme initiates the chemical digestion of carbohydrates in the mouth?

Answer 1

Salivary amylase

Question 2

What is a bolus? Chyme?

Answer 2

Bolus: A chewed up mass of food.

Chyme: A semi-fluid mass of partially digested food.

Question 3

What are the two main functions of saliva in the mouth?

Answer 3

1. moistens and lubricates food
2. produces salivary amylase

Question 4

Does digestion and/or absorption occur in the esophagus?

Answer 4

Neither! The esophagus ONLY functions in transport.

Question 5

What is the function of the esophagus?

Answer 5

Peristalsis

Question 6

What are the three major cell types located in the gastric glands of the stomach?

Answer 6

1. parietal cells (secrete HCl and intrinsic factor)
2. chief cells (secrete pepsinogen)
3. mucous cells (secrete mucus)

Intrinsic factor absorbs vitamin B12.

Question 7

The stomach has a low pH of 2 due to the presence of HCl. What is the significance of HCl?

Answer 7

• denatures proteins
• kills harmful bacteria
• converts pepsinogen into pepsin

Question 8

The pyloric glands of the stomach contain G cells that secrete gastrin. What are the two main functions of gastrin?

Answer 8

1. stimulates parietal cells to secrete more HCl
2. signals the stomach to contract, mixing its contents to form chyme

Question 9

The stomach secretes mucus. Why is this secretion very important?

Answer 9

• prevents autodigestion (the stomach from digesting itself)
• protects the stomach lining from its own acid

Question 10

What is the main function of HCl secreted by the parietal cells of the stomach?

Answer 10

Converts pepsinogen (inactive form) into pepsin (active form).

Question 11

What is the function of pepsin in the stomach?

Answer 11

Digests proteins

(works best at a very acidic/low pH, which is ONLY present in the stomach)

Question 12

Does digestion and/or absorption occur in the stomach?

Answer 12

Mainly digestion.

Question 13

What are the three segments of the small intestine?

Answer 13

1. duodenum
2. jejunum
3. ileum

Question 14

[Mnemonic]

Dow Jones Industrial

(how to remember the order of the small intestine)

Answer 14

Dow Jones Industrial

• Duodenum
• Jejunum
• Ileum

Question 15

In the digestive system, where does the most chemical digestion occur?

Answer 15

Duodenum

(The first segment of the small intestine.)

Question 16

The wall of the small intestine is lined with finger-like projections, called villi which are covered in microvilli. What is the function of both?

Answer 16

Increases surface area for better digestion and absorption.

Question 17

In the digestive system, where does the most absorption occur?

Answer 17

Jejunum and Ileum

(segments of the small intestine)

Question 18

Where in the small intestine are the fat-soluble vitamins (A, D, E and K) absorbed?

Answer 18

Ileum

Question 19

What are the four fat-soluble vitamins that dissolve directly into chylomicrons to enter the body?

Answer 19

1. Vitamin A
2. Vitamin D
3. Vitamin E
4. Vitamin K

Question 20

What is the main function of the large intestine?

Answer 20

Water absorption

(Absorbs what was NOT absorbed by the small intestine.)

Question 21

What are the three sections of the large intestine?

Answer 21

1. cecum
2. colon
   
   1. ascending colon
   2. transverse colon
   3. descending colon
   4. sigmoid colon
3. rectum

Question 22

Where are feces stored in the digestive system?

Answer 22

Rectum