Homeostasis and Behavior Flashcards
homeostasis
maintenance of an internal balance regardless of external environment
maintaining homeostasis increases…
fitness
adapting to land required…
managing water retention and loss
maintaining water balance relies on…
osmosis
changes in osmotic conditions / tonicity causes…
thirst - motivation to seek and ingest water
2 types of thirst
1) osmotic (intracellular thirst)
2) hypovolemic (extracellular thirst)
osmotic thirst
osmosensory neurons in the brain detect any increased osmolality of extracellular fluid
hypovolemic thirst
baroreceptors in major blood vessels detect any pressure drop from fluid loss
thirst is mediately directly by…
vasopressin (AVP/ADH) via salt balance
AVP causes…
water retention by kidneys
after max water retention is achieved by the kidneys, what occurs?
thirst is triggered
Brattleboro rats have a genetic mutation that…
leads to the inability to produce AVP; they lose copious amounts of water through urination and consume water to compensate
AVP release is triggered by…
osmoreceptors in the hypothalamus
2 brain regions involved in thirst
paraventricular nuclei (PVN)
supraoptic nuclei (SON)
hypovolemic thirst is mediated by…
renin-angiotensin-aldosterone system (RAAS)
renin causes release of angiotensin (parahormone in blood) that triggers…
release of aldosterone from adrenal glands which triggers drinking behavior (and salt uptake)
