Monday, 6 February 2012

2.89

2.88

 
2.88  Describe the role of the skin in temperature regulation, with reference to sweating vasoconstriction and vasodilatation
Hot (Can be detected by hypothalamus)
Blood vessels on your skin’s surface widens allowing more blood to flow to the surface thus more heat is lost through radiation
Sweat glands in your skin produce sweat, this evaporates and cools you down
Cold:
Blood vessels on the skin’s surface close up, cutting down the flow of blood to the surface and less heat is lost by radiation
Sweat glands stop producing sweat
When shivering the muscles start to contract quickly produces extra heat that warms the body
The hair erector  muscles contract and the hair  is pulled upright. This  would trap a layer of air  -which is a poor conductor of heat therefore it insulates your body
Vasodilatation is where  blood vessels widen  resulting from the relaxation of smooth muscle cells (especially in the large veins and arteries), this process is opposite to vasoconstriction which involves the narrowing of blood vessels

2.87 Function of the eye

2.86 Structure of the eye