14- homeostasis Flashcards
homeostasis
the maintenance of a constant
internal environment for the
organism to stay healthy.
warm blooded
-They maintain a constant body temperature despite
external environment changes. (mammals, birds)
-have mechanisms to lose / gain heat when too
hot or too cold.
when does negative feedback occur
when conditions change from the ideal or set point and returns conditions to this set point
hypothalamus
a part of the brain that acts like a thermostat detecting temperature of the blood going through it.
what does the hypothalamus do after it detects a change in heat
- changes are detected by receptors and sent as impulses to the brain through sensory neurons
- reflex action sends electrical impulses, along motor neurons, to effectors to regulate the temp
shivering
muscles contract and relax, to produce heat and warm body
vasoconstriction
arterioles near the skin become narrower so less blood can flow through them to conserve heat
other things that happen in the body to save and produce heat
- metabolism increases to release energy
- goosebumps
how are goosebumps produced
erector muscle contracts causing the hair to stand up
sweating
droplets of sweat evaporate, cooling the body
vasodilation
arterioles near the skin become wider so more blood can flow to loose heat
how do goosebumps help conserve heat
when the erector muscles are contracted, they stand up trapping air which is a great insulator
how are blood glucose levels controlled
by a negative feedback mechanism involving the production of two hormones (insulin and glucagon-made in pancereas)
when is insulin produced in body
when blood glucose rises
- goes to liver converts glucose in blood to stored glycogen
when in glucagon produced in body
when blood glucose falls
-goes to liver converts stored glycogen to glucose to be passed into the blood
