Exam 3- GI Hormones and Appetite Control Flashcards
what regulates food intake and energy balance?
hypothalamus
what is the term for something that stimulates the appetite?
orexigenic
what is the term for something that inhibits the appetite?
anorexigenic
what two subsets of neurons associated with appetite control does the arcuate nucleus in the hypothalamus have?
appetite center
satiety center
from where is the majority of the influence on the appetite center?
blood-borne factors: nutrient availability and peptide hormones produced in endocrine cells of the GI tract and adipose tissue
what hypothalamic neurotransmitters and neurohormones are involved in appetite control?
neuropeptide Y
orexin
melanocyte stimulating hormone (MSH)
what does neuropeptide Y (NPY) do?
stimulates appetite
what does orexin do?
stimulates appetite
promotes wakefulness
what does melanocyte stimulating hormone (MSH) do?
reduces appetite
what are the peptide hormones produced outside of the hypothalamus that influence appetite?
cholecystokinin (CCK)
peptide YY (PYY)
glucagon-like peptides (GLP-1, GLP-2)
insulin
ghrelin
leptin
what is cholecystokinin (CCK) released in response to and what does it do?
endocrine cells in small intestine release when lipids and proteins in intestine
stimulates secretion digestive enzymes from pancreas and contraction gallbladder
inhibits hypothalamic appetite center prior to digestion of food
what does peptide YY (PYY) do?
inhibits neuropeptide Y secreting neurons in hypothalamus: inhibits appetite
does glucagon-like peptide-2 (GLP-2) inhibit or stimulate appetite?
reduces appetite
what peptide hormone is produced in adipose tissue?
leptin
what does leptin do with appetite?
suppresses appetite: stimulates MSH-secreting neurons and inhibits NPY-secreting neurons
increases metabolic rate: activates sympathetic nervous system
what does leptin stimulate outside of appetite?
angiogenesis: growth of new blood vessels by stimulating mitosis of vascular endothelial cells
what does adiponectin do?
improves insulin sensitivity
inversely correlated with adipose tissue stores
what do elevated blood levels of amino acids do to appetite?
suppress appetite
what signals come from the satiety center?
inhibitory effect on appetite
what nerve carries inhibitory signals to the appetite center?
vagus nerve
what is ghrelin’s mechanism of action?
activates hypothalamic neuropeptide Y-secreting neurons
stimulates secretion of growth hormone from pituitary
what is adiponectin?
peptide adipokine
plasma levels inversely correlated with adipose tissue stores
what are the non-hormonal influences on appetite?
elevated blood glucose or volatile fatty acids (ruminants)
elevated blood levels of amino acids
ambient temperatures: cold stimulates, heat suppresses (neural interactions between temperature regulating centers and appetite control)
what hormone produced in the GI tract stimulates appetite?
ghrelin
what is the family of hormones with melanocyte stimulating hormone activity derived from post-translational cleavage of POMC?
melanocortins
