7 - Hunger and Satiety

Question 1

What is the hormone that triggers hunger as mealtimes approach?

Answer 1

Ghrelin

Question 2

What is the hormone that is secreted by the intestine after meals, acting as an appetite suppressant?

Answer 2

PPY

Question 3

What hormone is produced by adipose tissue?

Answer 3

Leptin

Question 4

As food enters the stomach, it distends, triggering ____ receptors via ____ nerve to brain stem (nucleus of ____ tract)

Answer 4

Stretch receptors
Vagus nerve
Solitary tract

Question 5

What is released from the small intestine, synergistically enhancing inhibitory effects of stomach distension?

Answer 5

Cholecystokinin (CCK)

Question 6

What kind of control (short or long term) does CCK exert?

Answer 6

Short term control

Question 7

What is the role of the nucleus of solitary tract / area postrema

Answer 7

• Integrates sensory signals from mouth to stomach, small intestine, panrceas and liver
• Sends signals to brain and brain stem
• Allows emotional/cognitive input

Question 8

What are the roles of the hypothalamus in regulating food intake?

Answer 8

Receive input from cortex, limbic system, and nucleus of solitary tract in brain stem

• Projects to brain stem - controlling vagus and other parasympathetic output of CNS and NST
• Controls fight or flight
• Regulates endocrine system

Question 9

Explain the role of the ob genes in mice.

Answer 9

Mice lacking gene ob are hyperphagic and obese

Leptin is produced by ob gene - transported across blood-brain barrier acting on hypothal.

Question 10

What is the dual centre hypothesis?

Answer 10

VMH (satiety centre) suppreses VLH (feeding centre)
VMH lesions = hyperphagic
VLH lesions = aphagia

Question 11

From group 1 neurons in the arcuate nucleus.
Is it catabolic or anabolic?
What are the 
A) peptides synthesised
B) Receptors
C) Actions on weight loss/feeding/energy

Answer 11

Catabolic
Peptides = alpha-MSH and CART
Receptors = MC3, MC4 in PVN,VMH,VLH
Actions = Less feeding, increased energy expenditure, weight loss

Question 12

From group 2 neurons in the arcuate nucleus.
Is it catabolic or anabolic?
What are the 
A) peptides synthesised
B) Where are the receptors
C) Actions on weight loss/feeding/energy

Answer 12

Anabolic
Peptides = NPY and AgRP
Receptors = in PVN, VLH
Actions = More feeding, decreased E expenditure, weight gain.