homeostasis Flashcards
where is the thermoregulation control centre
hypothalamus
what are the 4 types of heat loss. define them
evaporation
convection: heat up surronding air, new cool air comes in
conduction: contact with a solid surface
radiation: radio waves to the outside
Why does the body lose heat more quickly when immersed in water
water has much higher specific heat capacity therefore conductivity of heat will be much higher
what is it called when you lose heat via water evaporation through the mouth, nose etc
insensible heat loss
what are the two sort of sweat glands and where are they
appocrine mostly in axillae adn groin
eccrine for heat loss mostly all over
how do hair follicles assist in heat loss
hair muscles cause hair to lie flat to increase convection
what can happen in the hands to assist heat loss, how is it regulated
cutaneous vasodilation, regulated by ANS
what is shivering
uncontrolled muscle contraction brought about by thermoregulation c in hypothalamus in order to restore homeostasis
what is a by-product of most cellular processes
heat
name some non-shivering thermogenetic mechanisms
stimulation of brown fat - very inefficient at making ATP
catecholamines such as adrenalin and noradrenalin stimulate thermogenesis
thyroid hormones
how does piloerection work
traps warm air, prevents some convection
how does vasoconstriction happen in response to cold?
sympatheitic nervous activity increases, noradrenaline acts on alpha adrenoreceptors - smooth muscles contract (tunica media),
what are the vessels called that allow the capillaries of extremities to be bypassed in order to conserve heat
ateriovenous anastomoses
what can happen if there is prolonged exposure to cold
frostbite. blood flow decreases in extremities to protect core temperature.
what two activities are stimulated by glucagon
glycogenolysis in the liver
gluconeogenesis
