3.3.1 Controlling Body Temp

Question 1

Body temperature

Answer 1

37°C, optimum temp for enzymes

Question 2

Temp under 35°

Answer 2

Reduces core body temperature —> enzyme reactions occur too slowly —> respiration doesn’t release enough energy —> cells begin to die

Question 3

What Happens 40-42°C

Answer 3

Body overheats —> enzymes denature —> body réactions cannot occur —> may die

Question 4

Thermoregulatory system

Answer 4

Receptor cells in skin / internal receptor cells (blood temp)—> hypothalamus brain —> effectors= dermis (deep layer of skin)—> body returns to normal temp = homeostasis
NEGATIVE FEEDBACK

Question 5

What happens to body if too hot?

Answer 5

• Erector muscles relax = body hairs lie flat on skin = prevents air trapped
• sweat glands produce sweat (made of water + salt + urea)= as water evaporates it transfers energy from body to surroundings
• vasodilation= blood vessels supplying capillaries near surface of skin widen= increase in blood flow near surface= more heat lost by radiation/to surroundings

Question 6

What happens when body is too cold?

Answer 6

• Erector muscles contract = body hairs stand on end = traps layer of air closer to skin = insulates body
• sweat glands stop producing sweat
• vasoconstriction = blood vessels supplying capillaries near surface of skin narrow = reduces blood flow through capillaries near surface of skin = reduces heat lost to surroundings
• shivering begins= muscles contract and relax quickly = cells respiring quicker = transfer extra energy by heating