section 4

Question 1

explain Lipostatic hypothesis and Glucostatic hypothesis.

Answer 1

Lipostatic hypothesis Suggest that adipose tissues produce something to regulate appetite
Seen by hiberniting animals
Body requirement of fat accumulation that regulate amount needed

Glucostatic hypothesis: Insulin was already discovered. They is a balance glucose level and everything is produce to keep that glucose level

Question 2

(TF) visual and olfactory sensation doesn’t impact food intake.

Answer 2

False
food intake is regulated by endocrine, metabolic factors, visual, olfactory, taste sensation, memory, emotions and life conditions

Question 3

Explain briefly metabolic role these hormones:
Secretin
GIP
GLP-1
Ghrelin

Answer 3

Secretin: (from exocrine pancreas) help absorption in intestin
GIP: regulate incretin activity, help insulin and glucagon to regulate glucose level
GLP-1: also impact insulin and glucagon -> glucose level
Ghrelin: + stimulate NPY neurons -> eat more -> only orexic hormone

Question 4

What is the satiety center ?

Answer 4

VMH (Specific nuclei). by experiment of lesioning result to hyperphagia (animal overeat w/o VMH). Give signal eat enough

Question 5

What is the hunger center ?

Answer 5

lateral hypothalamus nucleus if lesion lead to anorexia (animal don’t know when to eat)

Question 6

What control the satiety and hunger center ?

Answer 6

SCN. regulated by light which regulate circadian rythym for whole body. lesion of SCN -> hyperphagia and obesity

Question 7

Which hormones regulate HPT (hypothalamus-pituitary thyroid) and HPA (hypothalamus-pituitary-adrenal) in central regulation of feeding ?

Answer 7

PVN and ARC

Question 8

Which 2 organs are crucial in central regulation of feeding ?

Answer 8

Hypothalamus and Brain stem (neurotransmetters)

Question 9

Explain briefly how alpha-MSH and NPY neurons regulate food intake.

Answer 9

They receive hormonal input from peripheral organs in Arcuate neurons and translate into signal to hypothalamus. alpa-MSH=anorexic; NPY=orexic
More fat -> more leptin -> + regulate a-MSH & inhibit NPY neurons -> anorexic hormone -> lipostatic hypothesis
Insulin (pancreas) -> inhibit NPY -> anorexic hormone
PYY and GLP -> inhibit NPY -> anorexic hormone
Grelin -> + stimulate NPY neurons -> eat more -> only orexic hormone

Question 10

Explain endocannabinoid system.

Answer 10

both endocannabinoid (AEA & 2-AG) are produce in tissues by enzymes -> GPCR receptors (CB1 and CB2) that inhibit cyclic AMP synthesis -. anabolic effect (store energy)

Question 11

What is the precursor of both endocannabinoids?

Answer 11

arachidonic acid

Question 12

what happend when inhibiting endocannabinoid system?

Answer 12

weight lost/ increase catabolism system
more satiety and less lipogenesis

Question 13

explain the blood supply to the pancreas.

Answer 13

aorta -> hepatic artery -> divide into smaller arteries different part pancreas

Question 14

explain the blood supply from the pancreas.

Answer 14

Splenic and mesenteric veins -> portal vein -> collect all blood from GIT -> liver to metabolize it

Question 15

Name each Islets of Langerhans and which hormone they secrete.

Answer 15

alpha-cells: Glucagon
beta-cells: Insulin
gamma-cells: Somatostatin
E-cells: Ghrelin
F-cells: Pancreatic polypeptide

Question 16

Which Islets of Langerhans received blood supply first?

Answer 16

Beta-cells detect glucose levels -> secrete insulin if needed

Question 17

Explain briefly beta-cells synthesis.

Answer 17

a lot of proliferation before 5yr old then decrease. lifespan of 25yrs. Stem cell in periphery of islets transform into beta cells when needed
B-differentiation -> stop being beta function before dying

Question 18

(TF) glucagon always stimulate insulin synthesis.

Answer 18

False. Glucagon stimulate insulin but also indirectly inhibit insulin (through somatostatin)

Question 19

(TF) C-peptide better representation of beta cells than insulin.

Answer 19

True

Question 20

(TF) C-peptide is metabolized by liver.

Answer 20

False. Insulin metabolized by liver and C-peptide metabolized by kidney

Question 21

What is the Glucagon synthesis progression

Answer 21

Preproglucagon -> proglucagon -> glucagon