Thermoregulation

Question 1

Thermoregulation t

Answer 1

the maintenance of body temperature within a range that enables cells to function efficiently

Question 2

Ectotherms 

Answer 2

Ectotherms depend on air temperature to regulate metabolic rates
 “cold-blooded”

 activity is regulated by environment

 behavioural adaptations enable these organisms to overcome this limitation (i.e. reptiles sun themselves on rocks when body temp gets too
low)

Question 3

Endotherms

Answer 3

maintain a constant body temperature regardless of environment
 “warm blooded”
 a decrease in temperature causes increase in cellular respiration rate to
produce heat

Question 4

Response to heat

Answer 4

Response to heat:
 sensors in brain detect a rise in body temperature, nerve message is coordinated with the hypothalamus(brain coordinating) center and a signal is sent to the sweat glands to initiate sweating
 evaporation of perspiration(sweat) from skin causes cooling
 nerve message also sent to blood vessels in skin causing
vasodilation
 vasodilation allows more blood flow to skin
 blood loses heat to the skin, blood returning from skin to core of body cools internal organs

Question 5

Response to cold:

Answer 5

Response to cold:
 thermoreceptors in skin send message to hypothalamus
 hypothalamus sends message to organs and tissues to increase body temperature
 nerves going to arterioles(small blood vessels that carry blood away from your heart) of skin cause smooth muscles to contract
and arterioles to constrict (vasoconstriction)
 limits blood flow and loss of heat from skin

 nerve messages also carried to smooth muscle that surrounds hair follicles causing hair to stand on end, erect hair traps warm, still air
next to skin surface reducing heat loss
 hypothalamus also sends nerve messages that initiate shivering, shivering is rhythmic contractions of skeletal muscle which generate, heat production by increasing metabolism