4.5.2.4 - Control of body temperature

What monitors our body temperature in our body?

The thermoregulatory centre in the hypothalamus in the brain monitors and controls our body temperature.

What does the thermoregulatory centre contain that helps it monitor and control our body temperature?

The thermoregulatory centre contains receptors that are sensitive to the temperature of the blood, the skin also contains temperature receptors and sends nervous impulses to the thermoregulatory centre

what temperature is our body kept at and why?

37 degrees Celsius

which is the optimum temperature for enzyme activity

give an example of thermoregulation.

e.g:
- temperature receptors in the skin detect that core body temperature is too high or too low and send nerve impulses to the thermoregulatory centre in the brain

- the thermoregulatory centre acts as a coordination centre - it receives the information from the receptors and triggers the effectors automatically

- Effectors (e.g sweat glands or muscles) produce a response and counteract the change returning the core body temperature back to normal

describe the mechanisms our body use when our core body temperature is too low...

All these occur to minimise the transfer of energy to the environment:

• sweat stops - so no sweat is produced

• hair erector muscles contract making hairs stand up and trap an insulating layer of air

• skeletal muscles contract automatically causing you to shiver. (which requires energy from cellular respiration which transfers thermal energy to warm our body)

• vasoconstriction ( as blood vessels supplying skin capillaries constrict)

describe vasoconstriction..

The process of blood vessels that supply capillaries near the surface of the skin constrict to reduce the blood flow near the surface and therefore reduce the heat energy lost to the surroundings

describe the mechanisms our body uses when our core body temperature is too high…

All these cause a transfer of energy from the skin to the environment:

• sweat is produced by sweat glands (which transfers heat energy to the surroundings when it evaporates from the skin)

• hair erector muscles in the skin relax causing hairs to lay flat

• vasodilation (when the blood vessels supplying skin capillaries dilate to increase blood flow and increase the energy transferred to the environment)

describe vasodilation..

The process of the blood vessels supplying the capillaries near the surface of the skin dilating and increase the blood flow so more (heat) energy is transferred from our skin to the surroundings