Biology · May / June 2024 · Paper 41 · Question 2

28.0 (°C) to 39.0 (°C) ;

any six from:

1

(internal temperature is maintained by) homeostasis / negative feedback ; 2

external temperature detected by, (thermo)receptors / sensory neurones, in the skin ;

3

(nerve) impulses (via sensory neurones) to the brain ;

4

change / increase / decrease in, blood / internal / core, temperature is detected by the brain ;

5

(nerve) impulses are sent (via motor neurones) to (effectors in) the skin ; 6, 7, and 8 when environmental temperature below body temperature / body is cold / before 3½ hours:

6

vasoconstriction / arterioles become narrow ;

7

decrease in blood flow (to capillaries), to / in, the skin ;

8

shivering / increase in metabolism (to generate heat) / hairs raised (to trap air for insulation) ;

9, 10 and 11 when environmental temperature above body temperature / body is hot / after 3½ hours:

9

(increase in) sweating / produce sweat ;

10 vasodilation occurs / arterioles widen ;

11 increase of blood flow (to capillaries), to / in, the skin ;

12 AVP ;

name of the part

letter in

role in maintaining internal body Fig. 2.2

temperature

fatty tissue

D

OR

insulation

hair

F

(contracts) to raise hair (to trap (hair) erector

E

heat) / (relax to) lower hair (to lose muscle

heat)

receptor / sensor

B

detect temperature changes

/ sensory neurone

;;;