Thermoregulation Flashcards
Why are humans described as ‘homeotherms’?
Because we maintain body temperature within very narrow limits despite wide fluctuations in ambient temperate.
How do body core and surface temperatures differ?
Body core temperature is maintained within very narrow limits, whereas body surface temperature can vary depending on the environmental conditions.
In women, when is body core temperature higher and why?
During the 2nd half of the menstrual cycle due to the effects of the hormone progesterone
How is body temperature maintained?
By balancing heat gain/production and heat loss
What are the 2 thermoregulatory responses to heat?
Vasodilation (increased skin blood flow to periphery)
Sweating
Why does vasodilation of blood vessels in the skin near the extremities occur?
It happens due to a reduction of sympathetic nervous stimulation
What are 2 thermoregulatory responses to cold?
Vasoconstriction (decreased blood flow to periphery)
Shivering
Why/how is shivering used as a response to the cold?
Muscular contraction releases heat because ATP is broken down.
In response to cold, voluntary movements increase, preventing core temperature to drop.
Shivering is a specialised form of muscular contraction where virtually all energy of contraction is converted to heat (result of stimulation by somatic motor neurons).
What is ‘hyperthermia’?
When core body temperature becomes dangerously high (38-40.5 degrees C)
