Green - Reg Of Food Intake Flashcards
Loss of appetite or lack of eating
Anorexia
Inhibits feeding
Anorexigenic
Overeating
Hyperphagia
Stimulates feeding
Orexigenic
Feeling of fullness and loss of hunger; sense of satisfaction that inhibits feeding center in hypothalamus
Satiety
Weight range at which adult animals stays w/o dieting or increased feeding
Set weight
What are short-term mechanisms which prevent overeating
Distention of stomach
(Stretch inhibitory signals transmitted by vagus nerve suppress feeding center)
GI hormones (secreted from intestine)
What does long-term food regulation do?
Maintains normal quant of energy stores
Mediated by blood gluc levels
______ is the control center for appetite and energy expenditure
Hypothalamus
What does the lateral nucleus of the hypothalamus do?
Feeding center
Stimulation - hyperphagia
Destruction - no desire for food
What does stimulation of the lateral nucleus of the hypothalamus do?
Causes hyperphagia
What does destruction of the ventrolateral nucleus do?
Causes voracious and continuous eating
What does stimulation of the ventrolateral nucleus do ?
Causes complete satiety
What is the ventrolateral nucleus’ function?
Satiety center
What do lesions of the paraventricular nucleus do?
Cause overeating
What do lesions of the dorsolateral nucleus do?
Depress eating behavior
What happens at the arcuate nucleus?
This is the location where multiple hormones from GI tract and adipose converge to reg food intake and energy use
Lacks complete BBB.
Convergence of Neuro and blood borne signals
Activation of POMC (proopiomelanocortin) neurons in the arcuate nucleus which produce alpha- MSH and CART does what?
Decreases food intake and increases energy expenditure
Activations of NPY-AgRP in the arcuate nucleus does ?
Increases food intake and reduces energy expenditure
__________ releases alpha-MSH which activates MCR 3 and MCR 4 which decreases food intake and increases energy expenditure
POMC
POMC release alpha-MSH which activates _____- and ______ and reduces food intake and increases energy expenditure
MCR3 and MCR4
POMC releases alpha-MSH which activates MCR3 and MCR4 which _______ and _______
Reduces food intake
Increases energy expenditure
Inhibition of MCR3 and MCR 4 does what?
Increases food intake and decreases energy expenditure
Most common cause of monogenic human obesity?
MCR-4 mutations
_______ is a natural antagonist of MCR-3 and MCR-4 (melanocortin receptors)
AgRP
Release of AgRP (increases feeding by inhibiting effects of alpha-MSH) is inhibited by _______
Insulin
Excessive formation of AgRP is associated with?
Excessive feeding and obesity
What do hypocretin/orexin do?
Promote food intake
Expression up during food deprivation
Neurons more active during fasting
Nicotine enhances firing of ______ neurons
POMC
Increased amount of adipose tissue causes a _____ amount of leptin
Increased
Leptin output _____ with insulin
Increases
Leptin is anorexigenic
Leptin output ______ w/ fasting and weight loss
Decreases
Leptin is anorexigenic
What does leptin do?
Goes to arcuate nucleus. Decreases NPY, AgRP.
Increases POMC products -> alphaMSH and CART
Decreases insulin secretion
Increases sympathetic to increase metabolic rate and energy use.
NPY stimulates food intake by :
Binding to Y receptors
AgRP stimulates food intake by binding to
MCR receptores
CART and aMSH ____ food intake by binding to MCR receptors
Inhibit
What does CCK do in regards to satiety?
Causes satiety.
1. By decreasing gastric emptying, increasing mechanostretch in stomach
- Affects brainstem and vagus nerve
Affect gone w/in 24 hours
What is the only known orexigenic (stimulates feeding) hormone
Ghrelin
Explain ghrelin
Ghrelin is the only known hormone that stimulates feeding (orexigenic)
It works by stimulating AgRP and NPY neurons.
It is increased by anorexia nervosa, weight loss, and cancer anorexia, as well as low calorie diets, stress, and sleep deprivation
Levels are decreased by weight gain and exercise
What increases ghrelin levels (x6)
Weight loss
Low calorie diet
Anorexia nervosa
Cancer anorexia
Sleep deprivation
Stres
What decreased ghrelin levels?
Weight gain
Exercise
Pro-glucagon derived peptide secreted from distal intestine in proportion to ingested calories
Anorexigenic (infusion quickly lessens hunger and food intake at single meal)
Repeated injections decrease body weight and increase activity related energy expenditure.
Oxyntomodulin
secreted by L cells in intestine after meal in proportion to caloric load (lipids>carbohydrates>proteins)
reduces gastric emptying and delays intestinal transit
anorexigenic
a. increased levels in disease states characterized by weight loss b. fasting plasma concentrations reduced in obese individuals
PYY