Homeostasis

1. Water content of the body
2. Heat
3. Sugar concentration

1. Temperature
2. Light intensity

1. Vasoconstriction is where the

Nota:

• Vasodilation is where the blood capillaries closes to the skin dilate in order to maximise heat loss when the body is too hot. 

Nota:

• Vasoconstriction is where the blood capillaries further away from the skin dilate in order to minimise heat loss and retain thermal energy. 

1. Evaporation of sweat

   Nota:

   • Cools the skin and creates heat loss. 
2. Radiation of heat from the blood
3. Hairs lie flat against the skin

   Nota:

   • This means that the warm still doesn't get trapped between the hairs and the body gets cooler. 

1. Vasodilation

   Nota:

   • The blood vessels don't dilate near to the skin in order to minimise heat loss across the epidermis. 
2. Erect hairs

   Nota:

   • They trap warm still air around the body. 
3. Sweat glands don't make sweat

   Nota:

   • So that the sweat doesn't cool the body. 
4. Shivering

   Nota:

   • Also one of the warming mechanisms in order to warm the body.