Hunger/Satiety DSA

Question 1

Insulin

Answer 1

• hormone that decreases appetite under endocrine control
• released from pancreas, can cross blood-brain barrier to bind to hypothalamic receptors which control food intake
• Type I diabetic patients with inadequate insulin have increased food intake
• potentiates satiety effect of gut hormones

Question 2

Leptin

Answer 2

• endocrine hormone that decreases appetite
• Released from adipose tissue, and crosses BBB and tells brain how much fat is stored.
• Receptors on neurons in arcuate nucleus
• stimulates melanocortin pathway and inhibits neuropeptide Y pathway
• As fat sores increase, leptin feeds back to inhibit feeding behavior and increase energy used
• Leptin resistance may be responsible for some obesity

Question 3

CCK

Answer 3

• released from duodenal mucosa in response to food higher in lipid content
• inhibits feeding via effects on vagal afferent fibers
• inhibits gastric emptying
• potentiates effects of leptin

Question 4

Peptide YY

Answer 4

• Released from enteroendocrine cells of ileum and colon by fat digestion products.
• inhibits gastric emptying and secretion
• promotes SHORT TERM satiety
• Crosses BBB and binds to Y2 receptor on hypothalamus directly
• Inhibits NPY neurons and stimulates POMC neurons
• acts on arcuate nucleus to suppress appetite
• low serum level associated with obesity

Question 5

Ghrelin

Answer 5

• secreted by oxyntic gland cells of stomach in response to fasting
• binds GH receptor to stimulate release of GH
• increases appetite
• stimulates neurons of NPY pathway
• acts directly on vagal afferents
• plasma level is low with obesity, therefore does not drive hunger in obese individuals. increases after weight loss due to dieting. promotes GH release.

Question 6

NPY/AGRP pathway

Answer 6

• hunger signals release NPto increase appetite
• binds to Y1 receptors to initate feeding and storage of calories
• Ghrelin stimulates this pathway
• stimulates desire for food

Question 7

POMC/CART ()Melanocortin pathway)

Answer 7

• appetite-inhibiting neurons containing POMC
• POMC inhibits food intake ad increases metabolism
• stimulated by Insulin, leptin, CCK
• mutation of MC4 receptor linked with obesity

Question 8

childhood obesity:

Answer 8

linked with mutation of MC4 receptor, which stimulates satiety by binding POMC (stimulated by leptin, CCK, insulin)

Question 9

arcuate nucleus of hypothalamus and nucleus tractus solitarius of hindbrain

Answer 9

regulates food intake and satiety/hunger signals

Question 10

endocrine system

Answer 10

provides long-term regulation via insulin released by pancreas and leptin released by fat cells - both of which limit food intake.