Exam 3- GI Hormones and Appetite Control

Question 1

what regulates food intake and energy balance?

Answer 1

hypothalamus

Question 2

what is the term for something that stimulates the appetite?

Answer 2

orexigenic

Question 3

what is the term for something that inhibits the appetite?

Answer 3

anorexigenic

Question 4

what two subsets of neurons associated with appetite control does the arcuate nucleus in the hypothalamus have?

Answer 4

appetite center
satiety center

Question 5

from where is the majority of the influence on the appetite center?

Answer 5

blood-borne factors: nutrient availability and peptide hormones produced in endocrine cells of the GI tract and adipose tissue

Question 6

what hypothalamic neurotransmitters and neurohormones are involved in appetite control?

Answer 6

neuropeptide Y
orexin
melanocyte stimulating hormone (MSH)

Question 7

what does neuropeptide Y (NPY) do?

Answer 7

stimulates appetite

Question 8

what does orexin do?

Answer 8

stimulates appetite
promotes wakefulness

Question 9

what does melanocyte stimulating hormone (MSH) do?

Answer 9

reduces appetite

Question 10

what are the peptide hormones produced outside of the hypothalamus that influence appetite?

Answer 10

cholecystokinin (CCK)
peptide YY (PYY)
glucagon-like peptides (GLP-1, GLP-2)
insulin
ghrelin
leptin

Question 11

what is cholecystokinin (CCK) released in response to and what does it do?

Answer 11

endocrine cells in small intestine release when lipids and proteins in intestine
stimulates secretion digestive enzymes from pancreas and contraction gallbladder
inhibits hypothalamic appetite center prior to digestion of food

Question 12

what does peptide YY (PYY) do?

Answer 12

inhibits neuropeptide Y secreting neurons in hypothalamus: inhibits appetite

Question 13

does glucagon-like peptide-2 (GLP-2) inhibit or stimulate appetite?

Answer 13

reduces appetite

Question 14

what peptide hormone is produced in adipose tissue?

Answer 14

leptin

Question 15

what does leptin do with appetite?

Answer 15

suppresses appetite: stimulates MSH-secreting neurons and inhibits NPY-secreting neurons
increases metabolic rate: activates sympathetic nervous system

Question 16

what does leptin stimulate outside of appetite?

Answer 16

angiogenesis: growth of new blood vessels by stimulating mitosis of vascular endothelial cells

Question 17

what does adiponectin do?

Answer 17

improves insulin sensitivity
inversely correlated with adipose tissue stores

Question 18

what do elevated blood levels of amino acids do to appetite?

Answer 18

suppress appetite

Question 19

what signals come from the satiety center?

Answer 19

inhibitory effect on appetite

Question 20

what nerve carries inhibitory signals to the appetite center?

Answer 20

vagus nerve

Question 21

what is ghrelin’s mechanism of action?

Answer 21

activates hypothalamic neuropeptide Y-secreting neurons
stimulates secretion of growth hormone from pituitary

Question 22

what is adiponectin?

Answer 22

peptide adipokine
plasma levels inversely correlated with adipose tissue stores

Question 23

what are the non-hormonal influences on appetite?

Answer 23

elevated blood glucose or volatile fatty acids (ruminants)
elevated blood levels of amino acids
ambient temperatures: cold stimulates, heat suppresses (neural interactions between temperature regulating centers and appetite control)

Question 24

what hormone produced in the GI tract stimulates appetite?

Answer 24

ghrelin

Question 25

what is the family of hormones with melanocyte stimulating hormone activity derived from post-translational cleavage of POMC?

Answer 25

melanocortins