35-RegulationOfFoodIntake

Question 1

short-term mechanisms of satiety sensing (x4)

Answer 1

• oropharyngeal receptors
• gastric distention
• intestinal nutrient sensing
• post-absorptive satiety (liver factors, portal vein)

Question 2

mechanism of gastric distension sensing

Answer 2

food intake
-> incr. mechanorecptor activity
-> incr. vagal
-> incr. NTS
-> decr. food intake

Question 3

NTS

Answer 3

Nucleus tractus solitarii

Question 4

mechanism of CCK gastric control

Answer 4

1. gallbladder contraction -> incr. bile release -> fat metabolism
2. pyloric constriction
3. gastric contractions

Question 5

mechanism of CCK satiety signaling

Answer 5

CCK released from duodenum
-> incr. CCK receptor activity
-> incr. vagal afferencents (mechanoreceptors)
-> incr. NTS
-> decr. food intake

Question 6

CCK

Answer 6

cholecystokinin, a hormone released from duodenum

Question 7

Ghrelin

Answer 7

hormone released by stomach

Question 8

mechanism of ghrelin cotnrol of satiety

Answer 8

fasting
-> release of ghrelin from stomach
-> incr. appetite (i.e. ghrelin is orexigenic)

Question 9

orexigenic

Answer 9

increases appetite

Question 10

increased leptin signals [increase or decrease] in food intake

Answer 10

decrease

Question 11

site of action for leptin (x2)

Answer 11

• brainstem
• hypothalamus

Question 12

LHA

Answer 12

lateral hypothalamic area

Question 13

lesion of LHA produces ___

Answer 13

aphagia (cessation of feeding)

Question 14

Peptides produced only in LHA

Answer 14

orexins

Question 15

Mechanism of LHA control of food intake

Answer 15

Activation of LHA
-> incr. anabolic
-> incr. orexin release
-> food intake

Question 16

PVN

Answer 16

paraventricular nucleus

Question 17

Mechanism of PVN control of food intake

Answer 17

PVN
-> parvocellular neurons send axons to brainstem
-> incr. ‘catabolic’ neurotransmitter
-> decr. food intake

Question 18

ARC

Answer 18

arcuate nucleus

Question 19

MEL/MSH-positive neurons

Answer 19

melanocortin-positive neurons

Question 20

MEL neurons project to ___ and ___ to [incr. / decr.] food intake

Answer 20

PVN and LHA, decrease

Question 21

Mechanism of ARC / MEL neuron control of food intake

Answer 21

leptin detected in ARC
-> activation of MEL neurons
-> decr. food intake

Question 22

NPY-positive neurons project both to ___ and ___ to [incr. / decr.] food intake

Answer 22

PVN and LHA, increase

Question 23

AgRP

Answer 23

endogenous melanocortin receptor antagonist

Question 24

Interaction between leptin and ARC / NPY to act on food intake

Answer 24

leptin inhibits NPY/AgRP neurons
-> decr. food intake

Question 25

Interaction between ghrelin and ARC to act on food intake

Answer 25

grelin
-> incr. NPY activity
-> incr. food intake