Obesity

Question 1

An increase in what turns on the ventromedial hypothalamus?

Answer 1

Blood glucose - from eating

Question 2

What two hormones does the paraventricular nucleus in the hypothalamus secrete?

Answer 2

Corticotropin-releasing hormone

Thyrotropin-releasing hormone

Question 3

What two areas of the hypothalamus are involved in the regulation of food intake?

Answer 3

Arcuate nucleus

Paraventricular nucleus

Question 4

Why is the arcuate nucleus a privileged site?

Answer 4

It can sample the peripheral circulation through semi-permeable capillaries in the underlying median eminence

Question 5

What is the PVN adjacent to?

Answer 5

The superior part of the third ventricle in the anterior hypothalamus

Question 6

What turns on the lateral hypothalamus?

Answer 6

A decrease in blood glucose - when someone is hungry

Question 7

What does a lesion of the VMH lead to?

Answer 7

Hyperphagia - excessive eating or increase appetite

Question 8

What is leptin and what is it produced by?

Answer 8

Adipostat - produced by adipose tissue

Question 9

What are leptin levels proportional to?

Answer 9

Body fat

Question 10

Which part of the brain does leptin act on?

Answer 10

Arcuate nucleus of hypothalamus

Question 11

What is the effect of leptin on the brain?

Answer 11

Inhibits circuits that stimulate eating and activate circuits that increase energy expenditure

Question 12

For which receptor is ghrelin an endogenous ligand for?

Answer 12

Growth hormone secratogogue receptor (GHS-R)

Question 13

What is the effect of insulin in the CNS?

Answer 13

Reduction in food intake

Question 14

Where is ghrelin produced?

Answer 14

The fundus of the stomach

Question 15

What are the two effects of ghrelin?

Answer 15

Stimulate growth hormone

Increase food intake

Question 16

What secretes peptide YY and when is it secreted?

Answer 16

From endocrine L cells of the small and large bowel

Release into circulation after meals

Question 17

What does peptide YY do?

Answer 17

Inhibits food intake

Question 18

What is co-secreted with peptide YY?

Answer 18

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

Question 19

What does GLP-1 do?

Answer 19

Inhibits feeding
Enhances insulin secretion
Suppresses glucagon secretion

Question 20

What releases neuropeptide Y?

Answer 20

Neurons that extend from arcuate nucleus to the paraventricular nucleus

Question 21

What stimulates secretion of neuropeptide Y?

Answer 21

Low leptin and insulin levels

Question 22

What does neuropeptide Y do?

Answer 22

Stimulates food intake

Question 23

When is there a rapid increase of neuropeptide Y in the PVN?

Answer 23

Before mealtimes and they remain elevated as long as food is withheld

Question 24

How does neuropeptide stimulate feeding?

Answer 24

Through activation of Y1 and Y5 receptors

Question 25

How does AgRP increase food intake?

Answer 25

Through antagonism of the melanocortin MC3 and MC4 receptors and thus block action of anorexigenic agonist alpha-MSH

Question 26

Are the effects of AgRP short- or long-lived?

Answer 26

Long-lived

Question 27

Where is AgRP exclusively found?

Answer 27

In neurons of arcuate nucleus

Question 28

What do virtually all AgRP neurone co-secrete?

Answer 28

Neuropeptide Y

Question 29

What are neuropeptide Y/AgRP neurons inhibited by?

Answer 29

Leptin | Insulin

Question 30

What are neuropeptide Y/AgRP neurons activated by?

Answer 30

Ghrelin

Question 31

What does alpha-MSH stand for, and what is it also known as?

Answer 31

Alpha-melanocyte-stimulating hormone, also known as alpha-melanocortin

Question 32

What stimulates the release of melanocortin?

Answer 32

Leptin

Question 33

What does melanocortin do?

Answer 33

Inhibit food intake

Question 34

What are melanocortins derived from?

Answer 34

Precursor molecule proopiomelanocortin (POMC)

Question 35

What does POMC give rise to in the anterior pituitary?

Answer 35

ACTH

Question 36

What does ACTH do?

Answer 36

Stimulates adrenal steroidogenesis

Question 37

What is co-expressed with POMC in the arcuate nucleus?

Answer 37

cocaine-and-amphetamine-regulated-transcipt (CART)

Question 38

What are classed as anorexigenic peptides?

Answer 38

CART | alpha-MSH

Question 39

In regards to serotonin, what drugs cause reduction in feeding?

Answer 39

Drugs that inhibit reuptake of serotonin or agonists of 5-HT receptors

Question 40

In terms of regulating appetite, what are the 3 important subregions of the hypothalamus?

Answer 40

Lateral Ventromedial Arcuate nucleus

Question 41

What region of the brain is thought to "know" your weight set point?

Answer 41

Lateral hypothalamus

Question 42

What does a lesion of the lateral hypothalamus cause?

Answer 42

A decline in body weight