Control of appetite

Question 1

Where is the appetite control centre located?

Answer 1

Hypothalamus

Arcuate nucleus

Question 2

What does nucleus mean?

Answer 2

A cluster of neurones

Question 3

What is the sensory function of primary neurones?

Answer 3

Sense nutrient and hormone levels in blood

Question 4

What is the sensory function of secondary neurones?

Answer 4

Recieve inputs from primary neurones

Question 5

What is the processing function of the secondary neurones?

Answer 5

Integrate the inputs recieved from the multiple different primary neurones

Question 6

What are the different types of primary neurones?

Answer 6

Stimulatory

Inhibitory

Question 7

How do stimulatory neurones affect appetite?

Answer 7

Stimulate appetite duh

Question 8

How do inhibitory neurones affect appetite?

Answer 8

Inhibit appetite duh

Question 9

Which peptides do stimulatory neurones release?

Answer 9

Neuropeptide Y (NPY)

Agouti-related peptide (AgRP)

Question 10

What do inhibitory neurones release?

Answer 10

POMC pro-hormone

Question 11

What does POMC produce?

Answer 11

ACTH

B-endorphin

a-MSH

Question 12

What are the hormonal signals released from the gut that affect appetite?

Answer 12

Ghrelin

Peptide tyrosine tyrosine (PYY)

Question 13

What releases ghrelin?

Answer 13

Stomach wall

Question 14

When is ghrenlin released from the stomach wall?

Answer 14

When the stomach is empty

Question 15

What effect does ghrelin have on the primary neurones? And hence on appetite?

Answer 15

Stimulates the stimulatory neurones

Promotes appetite

Question 16

What inhibits ghrelin release?

Answer 16

Filling of stomach

stretches stomach wall

Question 17

What releases PYY?

Answer 17

Cells of ileum and colon

Question 18

When is PYY released?

Answer 18

In response to feeding

Question 19

What effect does PYY have on the primary neurones? And hence on appetite?

Answer 19

Stimulates the inhibitory neurones
Inhibits the stimulatory neurones

Therefore suppresses appetite

Question 20

What abnormality of PYY signalling has been noticed in people who are obese?

Answer 20

Lack of response to PYY

Question 21

What are the hormonal signals released from the body that affect appetite?

Answer 21

Leptin

Insulin

Amylin

Question 22

Where is leptin released from?

Answer 22

Adipocytes

Question 23

How does leptin affect the primary neurones? And hence appetite?

Answer 23

Stimulates the inhibitory neurones
Inhibits the stimulatory neurones

Suppresses appetite

Question 24

How does leptin affect stage 4 of metabolism?

Answer 24

Increases expression of uncoupling proteins in mitochondria

Energy dissipated as heat

Question 25

How does insulin affect appetite?

Answer 25

Similarly to leptin

Question 26

Which is more significant in suppressing appetite - leptin and insulin?

Answer 26

Leptin

Question 27

Where is amylin released from?

Answer 27

B-cells of pancreas

Question 28

How does amylin affect appetite?

Answer 28

Suppresses appetite

Question 29

How does amylin affect glucagon?

Answer 29

Decreases glucagon secretion

Question 30

How does amylin affect the stomach?

Answer 30

Delays gastric emptying

Question 31

What is pramlintide? What is it used for?

Answer 31

Analogue of amylin

Used to treat type 2 diabetes

Question 32

What leptin abnormality has been discovered in some people who are obese? How is this treated?

Answer 32

Mutations in leptin gene
Gives loss of function of leptin

Leptin injections

Question 33

What have some people who are obese developed in relation to leptin?

Answer 33

Have developed resistance against leptin