GI Physiology 1

Question 1

What are the main functions of the stomach?

Answer 1

Temporary storage of food input

Mechanical digestion (breaking food into smaller particles)

Chemical digestion (breakdown of proteins)

Regulation of chyme output into the duodenum

Secretion of intrinsic factor for vitamin B12 absorption

Question 2

Name the anatomical parts of the stomach.

Answer 2

Gastro-Oesophageal Sphincter

Cardia

Fundus

Greater Curvature

Lesser Curvature

Body (Corpus)

Pylorus (and pyloric sphincter)

Question 3

What is the function of mucous cells in the stomach?

Answer 3

Secrete alkaline mucin to protect the stomach lining from acid

Question 4

What is the function of parietal cells?

Answer 4

Produce hydrochloric acid (HCl)

Question 5

What is the function of chief cells?

Answer 5

Produce pepsinogen, which is converted into pepsin to break down proteins

Question 6

What do G cells secrete and what is their function?

Answer 6

Secrete gastrin, which stimulates acid production

Question 7

How much hydrochloric acid (HCl) is secreted daily by the stomach?

Answer 7

2 liters per day

Question 8

What is the alkaline tide?

Answer 8

The release of bicarbonate (HCO3-) into the blood following acid production

Question 9

What is the role of intrinsic factor in the stomach?

Answer 9

It binds to vitamin B12 for absorption in the terminal ileum

Question 10

What regulates gastric emptying?

Answer 10

Volume in the stomach, chyme pH, and duodenal feedback mechanisms

Question 11

What are the three phases of gastric secretion?

Answer 11

Cephalic phase

Gastric phase

Intestinal phase

Question 12

What triggers the cephalic phase of gastric secretion?

Answer 12

Sight, smell, taste, or thought of food

Question 13

What stimulates gastric secretion during the cephalic phase?

Answer 13

Vagal stimulation and gastrin release

Question 14

What happens during the gastric phase?

Answer 14

Food distends the stomach, stimulating acid and enzyme secretion

Question 15

What inhibits gastrin release during the gastric phase?

Answer 15

Low stomach pH

Question 16

What triggers the intestinal phase?

Answer 16

Chyme entering the duodenum

Question 17

Which hormones inhibit gastric secretions during the intestinal phase?

Answer 17

Secretin, Gastric Inhibitory Peptide (GIP), and Cholecystokinin (CCK)

Question 18

What effect does fatty chyme have on gastric emptying?

Answer 18

It slows gastric emptying to allow digestion and absorption

Question 19

What are the three sections of the small intestine?

Answer 19

Duodenum

Jejunum

Ileum

Question 20

What is the primary function of the small intestine?

Answer 20

Digestion and absorption of nutrients

Question 21

What feature increases the surface area of the small intestine?

Answer 21

Villi and microvilli (brush border)

Question 22

What enzymes aid digestion in the small intestine?

Answer 22

Enzymes from the pancreas, bile, and intestinal wall amylase (carbohydrate digestion), lipase (fat digestion), and proteases such as trypsin and chymotrypsin (protein digestion).

Question 23

How is carbohydrate absorbed in the small intestine?

Answer 23

Broken down into monosaccharides and absorbed via co-transport with sodium

Question 24

How is fat absorbed in the small intestine?

Answer 24

Emulsified by bile salts, broken down into micelles, and absorbed passively

Question 25

What is the function of lacteals in the villi?

Answer 25

They absorb dietary fats into the lymphatic system

Question 26

What role does sodium play in nutrient absorption?

Answer 26

It helps co-transport glucose and amino acids across the intestinal lining via sodium-dependent active transport

Question 27

What are the exocrine functions of the pancreas?

Answer 27

Secretion of digestive enzymes such as amylase (carbohydrate digestion), lipase (fat digestion), and proteases (protein digestion), as well as bicarbonate to neutralize stomach acid.

Question 28

Which hormone stimulates pancreatic secretion?

Answer 28

Secretin

Question 29

Name the enzymes secreted by the pancreas.

Answer 29

Amylase (breaks down carbohydrates into maltose) Lipase (breaks down fats into glycerol and free fatty acids) Ribonuclease (breaks down RNA into nucleotides) Deoxyribonuclease (breaks down DNA into nucleotides) Proteases (e.g., trypsin, which breaks down proteins into peptides)

Question 30

What is the role of bicarbonate in pancreatic secretions?

Answer 30

Neutralizes acidic chyme entering the duodenum

Question 31

What are the main functions of the liver?

Answer 31

Protein synthesis (e.g., clotting factors) Metabolism of carbohydrates, proteins, and fats Detoxification of ammonia, hormones, and drugs Storage of glycogen and vitamins

Question 32

What structures make up the hepatic triad?

Answer 32

Hepatic portal vein, hepatic artery, bile duct

Question 33

What is the role of bile?

Answer 33

Aids in fat digestion and absorption

Question 34

Where is bile stored?

Answer 34

Gallbladder

Question 35

What stimulates bile release?

Answer 35

Cholecystokinin (CCK) and vagal stimulation

Question 36

What is bilirubin?

Answer 36

A breakdown product of hemoglobin

Question 37

Where is bilirubin processed?

Answer 37

Liver

Question 38

How is bilirubin excreted?

Answer 38

In bile via the intestines

Question 39

What condition can arise from excess bilirubin?

Answer 39

Jaundice

Question 40

What are the two forms of bilirubin?

Answer 40

Unconjugated (indirect) and conjugated (direct)