Digestive System

Question 1

The alimentary canal or gastrointestinal (GI) tract

Answer 1

digests and absorbs food

Question 2

Alimentary canal

Answer 2

mouth, pharynx, esophagus, stomach, small intestine, and large intestine

Question 3

Accessory digestive organs

Answer 3

teeth, tongue, gallbladder, salivary glands, liver, and pancreas

Question 4

There are six essential activities:

Answer 4

1. Ingestion
2. Propulsion
3. Mechanical digestion
4. Chemical digestion
5. Absorption
6. Defecation

Question 5

From esophagus to the anal canal the walls of the
GI tract have the same four tunics (layers)

Answer 5

mucosa, submucosa, muscularis externa, and serosa

Question 6

Three major functions of mucosa:

Answer 6

• Secretion of mucus – protects tissue from enzymes and acid
• Absorption of end products of digestion
• Protection against infectious disease

Question 7

Chemical Digestion: Carbohydrates

Answer 7

Starts in the mouth, finishes in small intestines

Question 8

How does the body absorb carbohydrates

Answer 8

via cotransport with Na+, and facilitated diffusion
Enter the capillary bed in the villi
Transported to the liver via the hepatic portal vein

Question 9

Enzymes used

Answer 9

salivary amylase, pancreatic amylase, and brush border enzymes

Question 10

Chemical Digestion: Proteins

Answer 10

Broken down in stomach, absorbed in small intestines
Absorption: similar to carbohydrates
Enzymes used: pepsin in the stomach
Enzymes acting in the small intestine

Question 11

Pancreatic enzymes

Answer 11

trypsin, chymotrypsin, and carboxypeptidase

Question 12

Chemical Digestion: Fats

Answer 12

Absorption: Diffusion into intestinal cells where
they:
Combine with proteins and extrude chylomicrons
Enter lacteals and are transported to systemic circulation via lymph

Question 13

Glycerol and short chain fatty acids are:

Answer 13

• Absorbed into the capillary blood in villi
• Transported via the hepatic portal vein

Question 14

Enzymes/chemicals used:

Answer 14

bile salts and pancreatic lipase

Question 15

Most ions are actively absorbed along the length of

Answer 15

small intestine

Question 16

Na+ is coupled with absorption of

Answer 16

glucose and amino acids

Question 17

Ionic iron is transported into

Answer 17

mucosal cells where it binds to ferritin

Question 18

Anions passively follow the electrical potential established by Na+
K+ diffuses across the

Answer 18

the intestinal mucosa in response to osmotic gradients

Question 19

Ca2+ absorption:

Answer 19

Is related to blood levels of ionic calcium
Is regulated by vitamin D and parathyroid hormone (PTH)

Question 20

95% of water is absorbed in the

Answer 20

small intestines by osmosis

Question 21

Water moves in both directions across

Answer 21

intestinal mucosa

Question 22

Net osmosis occurs whenever a …….. …….. is established by active transport of …….. into the ……. ……..

Answer 22

concentration gradient / solutes / mucosal cells

Question 23

What is reclaimed in the large intestine?

Answer 23

Vitamins, water, and electrolytes

Question 24

What’s the large intestine’s main function?

Answer 24

propulsion of fecal material
toward the anus

Question 25

Liver sinusoids

Answer 25

enlarged, leaky capillaries located between hepatic plates

Question 26

Kupffer cells

Answer 26

hepatic macrophages found in liver sinusoids

Question 27

Hepatocytes’ functions include:

Answer 27

Production of bile
Processing bloodborne nutrients
Storage of fat-soluble vitamins
Detoxification