Regulation Of Food Intake

Question 1

What part of the brain controls satiety and feeding?

Answer 1

Hypothalamus

Question 2

The hypothalamus includes (5)

Answer 2

Lateral nucleus (LH)
Ventromedial nucleus (VM)
Paraventricular nucleus (PV)
Dorsomedial nucleus (DM)
Arcuate nucleus (Arc)

Question 3

What 2 “systems” regulate energy balance?

Answer 3

Neural and hormonal systemms.

Question 4

Where does most of the integration signaling that regulates food intake and energy expenditure occur?

Answer 4

Arcuate nucleus

Question 5

What are the 2 pathways in the arcuate nucleus?

Answer 5

1. Anorexigenic pathway

2. Orexigenic pathway

Question 6

Anorexigenic pathway overview

Answer 6

Alpha-melanocortin (a-MSH) is released by POMC neurons.
A-MSH binds to MCR-4 in second order neurons.
–> decrease food intake

Question 7

What hormones activate the anorexigenic pathway? (3)

Answer 7

Insulin
Leptin
CCK

Question 8

Orexigenic pathway

Answer 8

Hunger signals stimulat NPY.
NPY binds Y1R.
AGRP is released, which antagonizes MCR-4.

Question 9

What hormone stimulates the orexigenic pathway?

Answer 9

Ghrelin

Question 10

In obese patients, they may have mutations in which genes? (2)

Answer 10

POMC

MCR-4

Question 11

How does the vagus n affect hunger?

Answer 11

It has the afferent fibers that stimulate hunger.

Question 12

Hormones released by which structures regulate feeding? (3)

Answer 12

GI Tract
Pancreas
Adipose

Question 13

Where is ghrelin secreted?

Answer 13

Endocrine cells of the stomach.

Question 14

What does ghrelin bind?

What does it stimuate?

Answer 14

Binds to GHSR and stimulates NPY –> orexigenic pathway.

Question 15

Actions of ghrelin

Answer 15

Increased appetite
Increased gastric motility
Increased gastric acid secretions.
Increased adipogenesis.
Decreased insulin secretions.

Question 16

What does insulin bind to?

Answer 16

POMC and NPY.
POMC +
NPY -

Question 17

Actions of insulin in feeding

Answer 17

Decreased appetite

Increase metabolism

Question 18

What is the association of insulin in pts with DM?

Answer 18

Increased food intake w/ decreased insulin released.

Question 19

CCK acts on what? To do what?

Answer 19

Vagus n –> NTS –> decrease ghrelin and increase gastric distension.

Question 20

PYY is released by what cells?

What does it do?

Answer 20

Released by L cells in ileum and colon after eating.

Binds to Y2R in hypothalamus to inhibits NPY.

Question 21

Lepin activates what pathway? Inhibits which one?

Answer 21

+ POMC
- NPY
(Decreases appetite, increases metabolism, decreased ghrelin)

Question 22

Obesity in children is associated with a failure to respond to which hormone?

Answer 22

Leptin

Question 23

What controls long-term regulation of energy balance?

What controls it in a meal-by-meal basis?

Answer 23

L-T is via adipose.

S-T is by gut peptides.

Question 24

Glucagon-like peptide-1 (GLP-1) functions (3)

Answer 24

Reduces food intake, suppresses glucagon secretion and delays gastric emptying.

Question 25

Oxyntomodulin function

Answer 25

Anorectic affect

Question 26

GLP-1 and oxyntomodulin are relases by which cells in which organ?

Answer 26

L cells in the intestine.

Question 27

Pancreatic peptide function (PP)

Answer 27

Decrease food intake

Question 28

Glucagon function in food intake

Answer 28

Decreased food intake

Question 29

Amylin inhibits which molecule, having an affect on which pathway?

Answer 29

• NPY –> anorectic affects

Question 30

Gut hormone targets for obesity therapies (4)

Answer 30

GLP-1
Oxyntomodulin
Leptin
Peptide YY

Question 31

3 kinds of bariatric surgery

Answer 31

RYGB
Gastric banding
Biliopancreatic diversion

Question 32

Physio changes after RYGB affect which kind of signaling?

What hormones become elevated soon after the operation?

Answer 32

Gut-brain.

GLP-1, PYY can remain elevated for almost 10 yrs.

Question 33

Anorexia nervosa

Answer 33

Self-starvation and weight loss.

Pts become malnourished –> dysfunctions in almost every organ system.