GI Appetite Hormones Flashcards Preview

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Flashcards in GI Appetite Hormones Deck (34):
1

hypothalamus eating centers

feeding center (lat): stim appetite
satiety center (ven): decrease appetite

2

Appetite hormones

ghrelin (up)
CCK (down)
glucagon-like peptide (GLP-1) (down)
peptide YY3-36 (PYY3-36) (down)

3

ghrelin made by

cells in stomach, SI, hypothalamus

4

ghrelin release stimulated by

goes up: before meals
goes down: after eating (esp protein). carbs are temporary.

5

ghrelin levels in obese/anorexic

decrease is absent or blunted w/ obesity
anorexics have chronically high ghrelin - ignore it

6

CCK made by

cells in duodenum and jejunum

7

CCK release stimulated by

respond to stretch/distension in GI nerves

8

CCK effect on brain

short-lived satiety

9

ghrelin effect on brain

increase appetite

10

GLP-1 made by

ileal L cells

11

GLP-1 stimulated by

nutrients in lumen of SI

12

GLP-1 actions

stim glucose dependent insulin secretion
suppress glucagon secretion
inhibit gastric secretion (delays absorption of carbs - makes you feel satiated)

13

PYY3-36 made by

L cells in SI/LI

14

PYY3-36 stim by

after meals

15

PYY3-36 actions

bind to NPY receptor (inhibit NPY secretion)
reduce appetite
inhibit gastric motility

16

NPY actions

up food intake
up fat storage
reduce anxiety/stress
reduce pain perception

17

NPY levels/times

high before meal and high as long as food is w/held

18

NPY stimulated by

low: leptin, insulin, PYY
high: ghrelin
(like it is while fasting)

19

agouti-related peptide (AgRP)

antagonist of alpha-MSH

20

agouti-related peptide actions

increase appetite

21

orexigenic factors

increase food consumption
NPY
AgRP

22

anorexigenic factors

decrease food consumption
leptin

23

leptin stimulated by

levels proportional to body fat

24

leptin actions

act on hypothalamus receptors
inhibit appetite (long-term)
"starvation signal" to maintain adequate fat

25

absence of leptin -->

uncontrolled food intake and obesity

26

leptin resistance mech

usually: feast --> up leptin --> down appetite
fattys: feast all the time --> up leptin --> down regulare receptors --> less regulation of appetite

27

insulin and leptin

insulin is leptin-antagonist
chronically high insulin blocks leptin signaling
why? @ puberty/pregnancy need to gain weight - hyperinsulinemic states

28

chronic cortisol levels

up food intake
down leptin
up ghrelin
+ makes you store fat in belly

29

endocannabinoid (EC) comes from

PHL in cell membranes
(esp omega-6 FAs)

30

EC actions

bind to CB-1 receptors -->
brain: stim caloric intake
liver, AT, skeletal muscle, GI: form and store lipids

31

EC and obesity

if EC system is overactivated --> weight gain, lipogenesis

32

blocking CB-1

EC's cant bind
down food consumption
up weight loss
down body fat
problem: suicidal tendencies

33

satiety vs continuing a meal

satiety signals make GABA released from pre-synaptic neurons to inhibit postsynaptic neuron from continuing the meal
blocked by palatable food, pleasing social, etc --> Ca up --> up EC (bind to CB1 on pre-synaptic) --> down GABA --> keep eating

34

alpha-MSH actions

stim satiety