The Digestive System Basics

Question 1

What can’t a person without a gallbladder do?

Answer 1

Store and concentrate bile.

Question 2

What stops a blood glucose concentration from dropping below a “set point”?

Answer 2

1. Glucose sparing by tissues other than neural tissue
2. Lipolysis in adipose tissue
3. Secretion of more glucagon
4. Glycogenolysis in the liver

Question 3

From which part of the GI tract is the most water absorbed?

Answer 3

The small intestine (through osmosis and is coupled with nutrient absorption).

Question 4

Where is insulin secreted from?

Answer 4

The beta cells of the pancreas.

Question 5

Where does most chemical digestion of food/chyme occur?

Answer 5

The small intestine.

Question 6

What are the functions associated with the GI system?

Answer 6

Motility, digestion, absorption & secretion.

Question 7

Name the “accessory organs” of the GI system.

Answer 7

Exocrine pancreas, liver, gallbladder, salivary glands.

Question 8

What is the cephalic phase of GI regulation?

Answer 8

Mediated by stimuli from the brain - sight, smell, taste, thought of food plus things like emotional state and stress levels.

Question 9

Where does the majority of carbohydrate digestion take place?

Answer 9

The small intestine.

Question 10

What is the role of the GI system?

Answer 10

To create optimal conditions for the transfer of nutrients, water and electrolytes from the external environment to the internal environment.

Question 11

What are the two types of digestion and what do they involve?

Answer 11

1. Physical - chewing, mixing, churning.

2. Chemical digestion - digestive enzymes, HCl

Question 12

How is enzymatic digestion achieved?

Answer 12

Hydrolysis.

Question 13

What does amylase break down?

Answer 13

Polysaccharides.

Question 14

What are the two enzymes that break down protein?

Answer 14

Pepsin and trypsin.

Question 15

Where does the vast majority of enzymatic digestion occur?

Answer 15

The small intestine.

Question 16

Where are vitamins and electrolytes absorbed?

Answer 16

The large intestine.

Question 17

What vitamins are produced by bacteria in the large intestine?

Answer 17

B & K

Question 18

Which organ secretes enzymes into the small intestine and which enzymes are they?

Answer 18

The pancreas. Amylase, trypsin and chymotrypsin, lipase.

Question 19

Where are the enzymes that are produced by the small intestine rather than the liver found?

Answer 19

Attached to the epithelial cells of the brush border.

Question 20

How do emulsifying agents work to digest fat?

Answer 20

They have a polar and non-polar side. The polar surface associates with water, non-polar with lipids. This results in smaller droplets = better access for pancreatic lipase.

Question 21

What are the two emulsifying agents and where do they come from?

Answer 21

1. Bile salts from bile.

2. Phospholipids from bile and ingested food.

Question 22

What is the makn energy source when in the absorptive state?

Answer 22

Glucose

Question 23

Where/how is glucose stored?

Answer 23

As glycogen in liver and skeletal muscle.

Question 24

Where/how are fatty acids stored?

Answer 24

As triglycerides in adipose tissue.

Question 25

Where/how are amino acids stored?

Answer 25

As proteins in skeletal muscle.

Question 26

What is the favoured energy source for ATP re-synthesis in the absorptive state?

Answer 26

Glucose

Question 27

What is glycogenesis?

Answer 27

Formation of glycogen from glucose.

Question 28

What is lipogenesis?

Answer 28

Synthesis of triglycerides from glycerol and fatty acids.

Question 29

What is glycogenolysis?

Answer 29

Break down of glycogen stores in liver and skeletal muscle.

Question 30

What is gluconeogenesis?

Answer 30

Amino acids, lactic acid and glycerol are converted to glucose in the liver and skeletal muscle.

Question 31

What is lipolysis?

Answer 31

The breakdown of lipids in the liver and adipose tissue to produce fatty acids and glycerol. Fatty acids used to synthesise ATP so glucose can be “spared” for use by nervous tissue.

Question 32

What is the major energy fuel in the post absorptive state?

Answer 32

Fatty acids.

Question 33

Which digestive state is anabolic?

Answer 33

Absorptive.

Question 34

Which digestive state is catabolic?

Answer 34

Post-absorptive.

Question 35

Where is glucagon secreted from?

Answer 35

Alpha cells in the pancreas.