Lec 13 - Food Intake

Question 1

3 pillars of food intake

Answer 1

• homeostasis
• reward/hedonic
• aversion

Question 2

2 systems that control homeostatic control of food intake

Answer 2

> short term system:
- mechanosensation
- chemosensation
- hormone release
- neural activation
long term system:
- maintence of adequate fat stores over long time

(remember theyre both intergrated)

Question 3

2 key components of energy balance

Answer 3

energy expenditure
energy intake

Question 4

energy surfeit

Answer 4

weight gain

Question 5

3 stages of short term homestatic

Answer 5

hunger
satitation (terminates individual meal)
satiety (fullness between meals)

Question 6

what are the 4 gut hormones that control short term control food intake

Answer 6

• CCK
• GLP-1
• GIP
• Ghrelin

Question 7

main adiposity signal

Answer 7

leptin

Question 8

what is gut brain axis

Answer 8

flow of info between GI tract and CNS

Question 9

orexigenic signal

Answer 9

stimulate feedback

Question 10

anorexigenic signal

Answer 10

inhibit feedback

Question 11

what are circumventricular organs (CVO)

Answer 11

structures that permit polypeptide hypothalamic hormones to leave the brain without disrupting the blood-brain barrier (BBB)

Question 12

what part of hypothalamus are key anorexegnic/orexigenic signal

Answer 12

arcuate hormones

Question 13

what do POMC neurons release

Answer 13

alpha-melanocyte stimulating hormone (aMSH)
= anorexigenic

Question 14

3 main orexegnic hormones

Answer 14

ALL released by AgRP/NPY neurons
AgRP (agouti related peptide)
NPY (neuropeptide Y)
GABA (a neurotrans which inhibits POMC neurons)

Question 15

what neurones does aMSH activate

Answer 15

MC4R neurons

Question 16

what action does AgRP have

Answer 16

inverse agonist of MC4R

Question 17

what does NPY do

Answer 17

inhibits PVH neurons

Question 18

what does GABA do

Answer 18

inhibit POMC neurons

Question 19

what is POMC cleaved by to make alphaMSH

Answer 19

PC1/3 and PC2

Question 20

mutations in what are mongenic causes of obsesity in humans and rodents

Answer 20

POMC, PC1 or MCR4 (most common)

Question 21

what is area postrema (AP)

Answer 21

a circumventricular organ
exposed to blood borne signals

Question 22

what is Nucleus of the solitary tract (NTS)

Answer 22

recieves input front afferent vagus nerve fibres
= main hub for neuronal input from GI tract

Question 23

what does the vago vagal circuit control

Answer 23

gastric motility
= if increased = enhanced hunger

Question 24

how, via leptin, does adiposity effect food intake

Answer 24

increase adiposity = increase leptin = an anorexigenic hormone
- activates POMC
- inhibits AgRP/NPY hormones

Question 25

what can chronic disruption of energy intake lead to

Answer 25

dysfunctional body weight:
e.g.
- obesity
- anorexia nervosa
- cancer induced cachexia

Question 26

what are most forms of obesity caused by

Answer 26

caused by a multi-factorial genes x environment interaction creating an imbalance
between energy intake and energy expenditure
(but could be monogenic, see previous flashcard)