Exam 6: hypothalamic control of eating Flashcards
What are the short-term signals that control food intake?
Gastric stretch, nutrients in the intestines, glucose and fatty acid sensors in liver
What are the satiety factors that act on the CNS?
Mechanoreceptors signal via vagal afferents to solitary nucleus to decreas food intake, cholycystokinin, ghrelin makes you want to eat more
What are the actions of cholecystokinin?
increase gallbladder contraction, increase pyloric constriction and gastric contractions
what are the CNS signaling pathways for CCK?
CCK receptors –> vagal afferents –> Solitary nucleus –> decreased food intake
What is the action of ghrelin?
increases appetite
What are symptoms of prader-willi syndrome?
fetal hypotonia, mental retardation, hypogonadotropic hypogonadism (leads to obesity and hyperphagia), increased ghrelin secretion
What is the long-term signal to control eating?
Adipose tissue releasing leptin
Where is the site of action of leptin?
brainstem (solitary nucleus) and hypothalamus
What does a lesion of the lateral hypothalamic area lead to?
aphasia (cessation of eating), due to loss of neurons that synethsize orexin
What does activation of paraventricular nucleus lead to?
release of corticotrophin hormone that leads to decreased eating
What are the two populations of neurons of the arcuate nucleus?
Neuropeptide Y neurons and melanocortin (POMC-derived peptide) neurons
What is the response of leptin in both the NPY neurons and melanocortin neurons of the arcuate nucleus?
Leptin inhibits NPY, activates melanocortin. Both leads to decreased food intake
What is NPY neurons of arcuate nucleus responsible for?
increased eating
What is malanocortin neurons of the arcuate nucleus responsible for?
Decreased eating
Where do neurons of the arcuate nucleus project to?
both Paraventricular nucleus and lateral hypothalamic area
