IB Biology SL D3.3 Homeostasis Questions

a. maintaining (stable) internal environment/conditions;
b. within (narrow) limits;
c. example (e.g. body temperature / blood pH / blood glucose / water / $\mathrm{CO}_{2}$ concentration);
d. levels of these variables are monitored (internally);
e. negative feedback mechanisms;
f. involves hormonal / nervous control;

a. maintained close to $36.7 / 37^{\circ} \mathrm{C} / 98.6^{\circ} \mathrm{F}$;
b. heat is transferred/distributed in body by blood;
c. hypothalamus contains thermoreceptors;
d. hypothalamus monitors temperature/sends message to effectors/causes response;
e. (vaso) dilation of skin arterioles warms skin/cools body;
f. (vaso) constriction of skin arterioles retains body heat;
g. skin/sweat glands produce sweat to cool the body when overheated;
h. removal of heat through evaporation of sweat;
i. shivering generates heat / increased metabolism / hair erection to retain heat;
j. example of behavioural change to warm/cool the body to thermoregulate;