injestive behavior--------- Flashcards
what are two types of thirst
osmotic thirst
hypovolemic thirst
why do people drink
chemical concentration in body fluids must be maintained for biochemical reactions to proceed.
osmotic thirst
diffusion of water
caused by eating salty foods or not drinking enough water
osmotic pressure
water flows from higher to lesser concentration. flows from where salt is low concentration to high concentration.
can salt cross cell membrane?
NO!
it sucks the water out of cells therefore they shrink in size.
dehydration is the shrinking of cells
vasopressin
helps combat osmotic thirst. increases blood flow
hypovolemic thirst (under volume)
caused by loosing body fluids (water and salt)
can be done by bleeding, diarrhea, profuse sweating.
what are salt cravings?
the outer area of a cell loses water, if you drink water, it makes the cells swell, but it doesn’t equalize the salt/water content.
adiposity
fat cells release a hormone LEPTIN. the more fat you have the more lepitin
what is LEPTIN
it circulates in blood and acts on neurons in hypothalamus. (makes you want to food intake decreases/physical activity increases)
hypothalamus role in feeding
later hypothalamus promotes hunger, initiates feeding, influenced by taste. you over eat yummy things.
paraventrical nucleus PVN
inhibits feeding. projects to later hypothalamus. DECREASES HUNGER
2 types of arcuate nucleus
hunger
satiety
