appetite Flashcards
hypothalamus and appetite: describe the major hypothalamic neuronal populations that regulate appetite, and how mutations in these systems can affect energy balance
diagram of major hypothalamic neuronal populations that regulate appetite
slide 3
what is body weight homeostasis
food intake = energy expenditure
3 inputs to hypothalamus to maintain body weight homeostasis
ghrelin, PPY and other gut hormones; neural input from periphery and other brain regions (e.g. afferent vagal nerve); leptin
hypothalamus: locations of paraventricular nucleus, arcuate nucleus, ventromedial hypothalamus and lateral hypothalamus
paraventricular nucleus dorsal to 3rd ventricle, arcuate nucleus bilateral and ventral to arcuate nucleus, ventromedial hypothalamus bilateral but most medial to 3rd ventricle, lateral hypothalamus bilateral to ventromedial hypothalamus
what is the key brain area of hypothalamus involved in regulation of food intake
arcuate nucleus
feature of arcuate nucleus to allow it to access peripheral hormones
incomplete blood brain barrier (median eminence)
what signals does the arcuate nucleus integrate
peripheral and central feeding signals
2 neuronal populations of arcuate nucleus, and whether stimulatory or inhibitory of appetite
stimulatory: NPY/Agrp neuron; inhibitory: POMC neuron
where do NPY/Agrp and POMC neurons extend to
cell bodies in arcuate nucleus, but axons extend to other hypothalamic and extra-hypothalamic regions
what neuronal population has mutations or deficiency, and what are these and what do they cause
POMC neuron by POMC deficiency (specifically a-MSH, causing pale skin and red hair; also affects ACTH so glucocorticoids deficient) and MC4-R mutations, which cause morbid obesity (no NPY or Agrp mutations)
