controlling body temperature

Why control body temp?

Needs to maintain at 37 as it is the optimum condition for metabolic reactions

If more than 4 above 37, enzymes denature - permanent damage

If lower than 37 efficiency = not optimum

Describe how brain monitors body temp

Hypothalamus controls thermoregulatory centre which measures blood temp detected by receptor cells, which are sensitive to stimulus .

Vasodilation

Vessels( arterioles )supplying blood to capillaries/skin dilate- inc blood supply close to skin

This helps transfer more energy from skin ti surroundings

Sweat

produced by sweat glands and evaporates from skin , transferring energy to the surroundings

Cooling by evaporation of water

Hairs lie straight

Vasoconstriction

Blood vessels ( arterioles ) supplying skin constrict and tighten so less blood flows through capillaries near skin. This helps reduce heat loss to surrounding

Shivering

Hair becomes stood up to trap an insulating layer of air

Involves involuntary muscle contraptions, increasing body temp.