Gastrointestinal Hormones and Appetite Regulation

Question 1

• What is the primary function of the GIT?

Answer 1

The digestion and absorption of nutrients

Question 2

• What types of signalling take place in the GIT?

Answer 2

Autocrine, paracrine, endocrine & neurocrine

Question 3

• What is the main difference between exocrine and endocrine cells in the GI tract?

Answer 3

Location of their secretory granules

Question 4

• How is GI function regulated?

Answer 4

Enteric nervous system & enteric endocrine system

Question 5

• What are the main GI hormones?

Answer 5

Insulin, glucagon, gastrin, secretin, cholecystokinin (CCK), gastric inhibiting peptide (GIP), ghrelin, motilin

Question 6

• What are the main GI regulatory hormones?

Answer 6

Gastrin, secretin, cholecystokinin, GIP, motilin

Question 7

• What inhibits the production of gastrin?

Answer 7

A fall in pH to below 3

Question 8

• What is secretin?

Answer 8

Bicarbonate secreted from the exocrine part of the pancreas

Question 9

• What are the main functions of CCK?

Answer 9

Stimulates secretion of pancreatic enzymes from exocrine pancreas & contraction and emptying of the gall bladder

Question 10

• What are the three phases of gastric secretion?

Answer 10

Cephalic – preparation of the body for eating and digestion
Gastric – presence of food in stomach and decrease in pH
Intestinal – partially digested food enters the duodenum

Question 11

• What are the main inputs to the hypothalamus controlling appetite regulation?

Answer 11

Neurons in arcuate nucleus, sensing blood glucose and hormones, satiety centre, appetite centre

Question 12

• What are the four theoretical regulators of appetite?

Answer 12

Lipostat, gut peptides, glucostat, thermostat

Question 13

• What is the anorexigenic hormone involved in the lipostat hypothesis?

Answer 13

Leptin – acts on the hypothalamus to decrease food intake and increase energy output

Question 14

• What are the gut peptides involved in appetite regulation?

Answer 14

CCK, PYY & ghrelin

Question 15

• Where does PYY act?

Answer 15

Upon receptors in arcuate nucleus

Question 16

• Which of the gut hormones involved in appetite regulation is orexigenic?

Answer 16

Ghrelin

Question 17

• What is the glucostat hypothesis?

Answer 17

High glucose – satiety centre stimulated (amino acids do the same)

Question 18

• What are the main two hormones involved in appetite regulation?

Answer 18

Ghrelin & leptin