Chapter 12 Flashcards
where is temperature controlled?
thermoregulatory centre
where is the thermoregulatory centre?
the hypothalamus, brain
how does the thermoregulatory centre detect changes?
receptors test temperature of blood in brain
receptors in skin
how dos the body cool down
sweat
vasodilation
what is vasodilation?
the blood vessels near the skin dilate so more blood is exposed to the cool air and cools down
how does sweat cool you down?
it evaporates from the skin taking heat with it
how does the body warm up
vasoconstriction
shiver
hairs stand on end
how does hair standing on end warm you up?
it catches and traps an insulating layer of air
how does shivering warm you up?
the movement of the skeletal system means more respiration (an exothermic process). this heats up body
what is vasoconstriction and how does it warm you up?
blood vessels constrict near the skin so less blood is available to the cold air
why should the body not get too hot?
denatures enzymes
what are the two main waste products?
carbon dioxide and urea
when is carbon dioxide produced?
respiration
why is carbon dioxide so dangerous?
when it dissolves, it produces acid which effects the enzymes in cells
how do you get rid of CO2
diffuses from cells into blood stream
diffuses from blood stream into lungs
this air is exhaled
how is urea produced?
breakdown of excess amino acids turns into ammonia, which turns into urea
where is urea produced?
liver
why is urea dangerous?
it is poisonous to cells
how do you get rid of urea?
kidneys filter it out
3 ways in which you lose water from body
exhaling
sweat
urine
function of kidneys
filters substances like urea from the blood
maintains a healthy water level
how do the kidneys conserve water?
you produce very concentrated urine with not much water