I didn't do Either, but I think I can still answer them if I
want. Any questions?
Confirming my answers :)
Can't remember the exact question but it's along the lines
of,
(a) "In extremely cold conditions, the cells in fingers and toes
die. This is frostbite. Explain why wearing thick gloves, socks and
shoes does not prevent frostbite." [5]
I wrote that the constriction of arterioles and dilation of
shunt vessels prevents the flow of blood to the capillaries in the
skin, thereby cutting off blood supply to the skin. Fingers and
toes contain capillaries. When the blood supply is cut off for too
long, the cells in fingers and toes do not receive oxygen for
respiration or nutrients vital for survival, and the cells will
eventually die. This is frostbite. Thick gloves, socks and shoes
only prevent heat loss through radiation or convection, and do not
prevent the cutting off of blood supply to the skin. (I also added
in redundant parts about the sweat production decreasing and
metabolic rate increasing to lengthen my answer)
(b) "In cold conditions, shivering takes place. Explain why this
happens." [3]
When production of sweat is decreased, metabolic rate is
increased and blood flow to the skin is stopped is not sufficient
to reduce heat loss and increase body temperature back to normal,
this stimulates us to shiver. Movements in the muscles warm the
body up.
(c) "Explain how the mechanics for control of body temperature
are synchronised." [2]
They are synchronised by homeostasis. When the hypothalamus
detects the body temperature rising above or falling to below
average, the brain sends signals to various body parts to work to
increase or decrease body temperature, depending on if the body
temperature is below or above normal.
Something like that.