4.5.2.4 Control of body temperature (biology only)

Body temperature:

monitored and controlled by the thermoregulatory centre in the brain

The thermoregulatory centre:

contains receptors sensitive to the temperature of the blood

The skin:

- contains temperature receptors

- sends nervous impulses to the thermoregulatory centre

Increase in body temperature...

due to increase in respiration during exercise

If the body temperature is too high: Receptors

temperature receptors in skin and in thermoregulatory centre (in the brain)

If the body temperature is too high: Coordination Centre

Body temperature is monitored and controlled by the thermoregulatory centre (in the brain)

If the body temperature is too high: Effectors

Muscles in:

- blood vessels under skin

- sweat glands

If the body temperature is too high: Response

- these muscles relax

- vasodilation of blood vessels

- more sweat is released from sweat glands

If the body temperature is too high: Response EXPLANATION

Both these mechanisms cause a transfer of energy from the skin to the environment, cooling the body down

Decrease in body temperature...

due to temperature of surroundings falling

If the body temperature is too low: Receptors

temperature receptors in skin and in thermoregulatory centre (in the brain)

If the body temperature is too low: Coordination Centre

Body temperature is monitored and controlled by the thermoregulatory centre (in the brain)

If the body temperature is too low: Effectors

Muscles in:

- blood vessels under skin

- supplying capillaries

If the body temperature is too low: Response

- skeletal muscles involuntarily contract (shiver)

- vasoconstriction of blood vessels

- stop sweat being released from sweat glands

If the body temperature is too low: Response EXPLANATION

- These mechanisms reduce heat loss to the surroundings

- skeletal muscle contraction increases heat released in the body

Negative feedback

a mechanism where any movement away from ideal conditions results in changes occurring which bring them back