2.88 Skin

2.88 describe the role of the skin in temperature regulation, with reference to sweating vasoconstriction and vasodilation

- Homeostasis is the act of keeping conditions steady inside the body.

- It is important to keep the body temperature at 37 oC because enzymes work best at this temperature. Any slight change int he conditions can slow down or stop the enzyme from working.

- The skin controls the temperature within our body.

- Temperature is one of the factors controlled by the negative feedback system as well as blood sugar the water levels. If there are any changes in the surrounding environment, the system will try to minimize the changes.
- Stimuli: blood temperature
- Receptor/co-ordinator: Hypothalamus
- Effector: Skin
- Latent heat of evaporation

When the temperature is low - cold:

- There is less sweating

- Hair erection - when the hair muscles contract and this traps a thicker layer of air --> cuts down more on heat loss

- Vasoconstriction - the capillaries narrow and therefore, carry less blood --> more heat kept inside the body

- There is insulation from a layer of fat underneath the skin 

- Shivering releases extra heat from increased respiration

When the temperature is high - hot:

- More sweating for evaporation ---> reduces the amount of heat

- Hairs lie flat - hair muscles relax and less air is trapped close to the skin ---> more heat lost by radiation

- Vasodilation - the capillaries widen and therefore, carry more blood ---> the heat can be transferred out of the body via conduction and radiation.

- There is no shivering.