homeostasis and thermoregulation Flashcards
homeostasis is the maintenance of a state of …
dynamic equilibrium
constant internal environment
what are the factors that need to be controlled in homeostasis
pH
temperature
water potential
what is negative feedback
the body’s mechanism for reversing a change so that it returns to the optimum
what are the stages involved with negative feedback
stimulus
receptor
co-ordinator
effector
response
what is the normal human body temperature
37 degrees
what happens in extreme temperatures to the cells
cause the proteins in the cell membrane to denature, causing cell death
what is body temperature monitored and controlled by
thermoregulatory in the hypothalamus in the brain
what does the thermoregulatory monitor
temperature of the blood, also receives nerve impulses from receptors in the skin
what does the control of body temperature involve
automatic nervous system
what is the automatic nervous system divided into
sympathetic
parasympathetic
what is the role of the sympathetic nervous system
increases, speeds up processes in the body: dilate pupils, increases heart beat
what is the role of the parasympathetic nervous system
decreases, slows down processes into the body: constricts pupils, decreases heart beat
sympathetic nervous system helps to … body temp, parasympathetic nervous system helps to … body temp
increase
decrease
what happens to sweat glands in the skin if the core body temp is too high
sweat is produced, evaporates from the skin, transferring heat energy to the environment
what happens to the hairs on the skin if the body temp is too high
hairs lie flat
what happens to the arterioles leading to capillaries in the skin if the core body temp is too high
nerve impulses sent through the parasympathetic to the arterioles
blood vessels dilate (vasodilation) more blood flows to the skins surface
what happens to the liver cells if the core body temp is too high
rate on metabolism reduces, less heat generated from reactions like respiration
what happens to the skeletal muscles if the core body temp is too high
no spontaneous reactions
what happens to the sweat glands in the skin if the core body temp is too low
sweating stops, reducing transfer of heat energy to the environment
what happens to the hairs on the skin if the core body temp is too low
hairs stand up
what happens to the arterioles leading to the capillaries in the skin if the core body temp is too low
nerve impulses sent through the sympathetic nervous system to the arterioles
blood vessels constrict (vasoconstriction) less blood flows to the skins surface
what happens to the liver cells if the core body temp is too low
rate of metabolism increases, respiration generates more heat transferred to the blood
what happens to the skeletal muscles if the core body temp is too low
rapidly contract (shiver) respiring, transferring heat energy from glucose
what is the cause of hyperthermia
body temperature is too high, and usual cooling methods do not work - over exertion in hot weather
