Describe the physiological (non-psychosocial) mechanisms that influence food intake. Include the following in your answer : CCK, NTS, ghrelin, PYY, insulin, leptin, NPY, melanocortins, orexins, and CRH
What will be an ideal response?
As time between meals increases, the stomach secretes more ghrelin, a hormone that causes the hypothalamus to secrete neuropeptide Y (NPY). The NPY inhibits the NTS (satiety center) in the brain stem and causes the release of orexins in the hypothalamus. Orexins initiate appetite-enhancing pathways leading to food intake. After food intake, stretch receptors in the stomach initiate nerve signals that stimulate the NTS, which sends signals to the hypothalamus to suppress appetite. Food intake also causes the release of CCK and PYY from the small intestine. CCK stimulates the NTS directly, while PYY inhibits the production of NPY, but the effect in both cases is suppression of appetite. Food intake causes the pancreas to release insulin, which stimulates the storage of fat. As fat deposits increase, adipocytes secrete the leptin, a hormone that inhibits the release of NPY and stimulates the release of melanocortins in the hypothalamus. Melanocortins inhibit the release of orexins and stimulate the release of corticotropin-releasing hormone that results in suppression of appetite.
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What will be an ideal response?
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Indicate whether the statement is true or false
Answer the following statements true (T) or false (F)
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Ablation of the ________ in the midbrain would impair the ability to respond to sounds.
A. inferior colliculi B. substantia nigra C. red nucleus D. medial colliculi