Regulation of energy intake Flashcards
- Describe the roles of the arcuate nucleus and the paraventricular nucleus
Arcuate- acts on paraventricular
- NPY/AgRP pathway is the anabolic pathway
- NPY activates NPY receptor in the PVN to increase anabolic drive (Leptin and insulin inhibit this pathway) - AgRP inhibits MCR in the PVN stopping the catabolic pathway
- POMC/CART (MSH) pathway acts on the MCR which is the catabolic pathway
- leptin and insulin upregulate this
- Describe the mechanisms used by the hypothalamus to promote and inhibit food intake, and predict the impact on food intake and body weight of: a. ‘knocking out’ the POMC gene (and therefore, -MSH) b. ‘knocking out’ the NPY gene c. loss-of-function mutations in the melanocortin receptor (MCR)
Knock out POMC- u become obese
knock out NPY you decrease food intake and increse energy expendicture
- Describe the role of peripheral hormones derived from the GI tract (ghrelin, cholecystokinin, gastrin releasing peptide, glucagon-like peptide), pancreas (insulin, glucagon), and adipose tissue (leptin) in regulating food intake and body weight.
ghrelin- stomach hormone that makes us feel hungry
-upregulates NPY, downregulates POM CCART
PYY- distal ileum inhibits food intake
-downregulates NPY, up regulates POM CCART
Leptin and insulin- inhibit food intake
CCK- inhibit food intake
GLP-1 inhibits food intake
- Discuss the role of brain reward pathways and environmental cues in the development of obesity.
reward pathway is active with food
we have homeostatic dysregulation of food intake
non homeostatic factors(environmental cues, availability, social context, time cues) can influence homeostatic factors (reard mechanisms, craings, focus on food, reatraint, leatrned behavior, attention)
obese prone have persistent attention, reward, motivation and memory involved with food
ventromedial nucleus
Ventromedial nucleus- satiety center
lateral hypothalamus
lateral nucleus- hunger center
