Feeding Regulation Flashcards
Where are feeding control centers located in the brain? What are some of the major areas?
Hypothalamus
Lateral nucleus (feeding center), paraventricular nucleus, and arcuate nucleus (central control region)
What affect does the anorexigenic pathway have on feeding?
Explain the pathway
What hormones regulate the pathway
Anorexigenic pathway decreases food intake/appetite
POMC neurons release alpha-MSH which binds MCR-4 in the paraventricular nucleus to increase NTS sensitivity to dec appetite
Insulin, CCK, and leptin all stimulate this pathway
What effect does the orexigenic pathway have on appetite?
Explain the pathway
What hormones regulate this pathway
Orexigenic pathway increases appetite and food intake
Hunger stimulates NPY release which binds Y1R in the lateral hypothalamus which dec sensitivity of NTS to inc feeding
Ghrelin stimulates this pathway
If vagal stimulating is blocked, what is the effect on meal size with regards to stomach contents?
Block vagal stimulation -> contents in stomach have no influence on meal size
Where is Ghrelin secreted from?
What are its actions?
Ghrelin is secreted from gastric endocrine cells
Ghrelin binds GHSR and stimulates NPY(orexigenic pathway) to increase feeding
Ghrelin increases appetite, gastric motility, HCl secretion
Ghrelin decrease insulin secretion
What are the actions of insulin?
Insulin binds receptors that inhibit NPY (orexigenic) and stimulate POMC (anorexigenic) pathways to decrease appetite and increase metabolism
What effect does CCK have on the vagal-NTS-hypothalamus circuit?
CCK decreases ghrelin secretion to elicit fullness
What cell releases PYY?
What are PYY actions?
PYY is released from L cells
PYY binds Y2R to inhibit NPY (orexigenic)
What cells secrete leptin?
What are its actions?
Leptin is secreted from adipose cells
Leptin binds receptors to inhibit NPY and stim POMC to decrease appetite and ghrelin release and increase metabolism
Are leptin levels elevated or decreases with obesity?
Leptin levels are elevated with obesity leading to leptin resistance
When is GLP1 secreted?
What are its actions?
GLP1 is secreted with PYY following a meal
GLP1 reduces food intake, suppresses glucagon, and slows gastric emptying
What cells release oxyntomodulin?
What effect does it have?
Oxyntomodulin is released from L cells and has a anorexigenic effect
What hormones are affected following a gastric bypass?
GLP1 and PYY (which are co-secreted) will be elevated following a gastric bypass which results in decreased feeding
Anorexia nervosa
- how are leptin levels affected?
- what happens to ghrelin?
- which hormone contributes to decreased nutrient intake?
Leptin levels are reduced due to reduction of adipose
Ghrelin resistance develops
PYY levels are elevated which decreases food intake
