Thermoregulation

Thermoregulation

Regulation of body temp

Too High

Denature enzymes

Nerve disfunction

Change protein structure

Too Low

Slow rate of reactions - respiration

Metabolic Rate

Rate at which energy released by breakdown of food

Conduction

Transfer of heat by direct contact between particles

Convection

Transfer of heat by movement of liquid/gas

Radiation

Transfer of heat by infrared radiation emitted as waves

Evaporation

Process of liquid forming gas, absorbing heat

Warm Up - physiological

Vasoconstriction

Shivering

Stimulation of adrenal medulla

Increase thyroxine

Warm up - behavioural

Increase voluntary activity

Clothing

Reduce surface area

Cool Down - physiological

Vasodilation

Sweating

Decrease thyroxine

Cool Down - behavioural

Decrease voluntary activity

Shade

Clothing

Vasoconstriction

Narrowing of blood vessels to minimise heat loss from skin via convection/radiation

Vasoconstriction Process

Hypothalamus send impulse

Stimulate sympathetic nerves

Blood vessels constrict

Decrease flow of warm blood from internal organs to skin

Vasodilation

Widening of blood vessels to increase heat loss from skin via convection/radiation

Vasodilation Process

1. Hypothalamus send impulse

2. Stimulate ANS

3. Blood vessels widen

4. Increase flow of warm blood to skin

Shivering

Oscillating, rhythmic muscle tremors that increase heat production

Shivering Process

1. Hypothalamus send impulse

2. Stimulate skeletal muscle contraction

3. Increase heat production

4. Cerebral cortex can consciously suppress

Stimulation fo Adrenal Medulla

Sympathetic nerves stimulate adrenaline/noradrenaline secretion

Sweating

Active secretion of fluid from sweat glands

Sweating Process

1. Hypothalamus send impulses

2. Stimulate sympathetic nerves

3. Increase secretion from sweat glands

4. Heat loss from skin when liquid forms vapour

5. Cooling effect