Saturday, 23 February 2013

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

Sweating- when too hot, glands under the skin secrete sweat, this increases heat loss by evaporation.
Vasoconstriction- blood vessels by the skin shrink, this reduces the blood which runs by the surface meaning less heat can be lost to the air.
Vasodilation- blood vessels by the skin grow, this means that more blood, and so more heat, is travelling near the surface of your body, in this way heat will be lost as it is conducted by the air.

8 comments:

  1. I have found this blog really helpful, thank you! I was also wondering if you have done your GCSEs yet, and if so what did you get? Or are you taking them this summer?

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    1. I've also found this blog really helpful!! taking my bio exam this june

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  2. Vasodilation => when the blood vessels supplyong your skin capillaries dilate, blood flows into the capillaries, you flush and lose heat by radiation through your skin.

    Vasoconstriction=> if the blood vessels constrict, the warm blood is kept deep in your body so that less heat is lost.

    Very helpful!

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  3. Sweating cools you down as when the sweat evaporates the energy causing it to do so is provided by the body this is called the latent heat of vaporisation

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  4. Replies
    1. Did you mean 2.90 if so here:2.90 understand the sources, roles and effects of the following hormones: ADH, adrenaline, insulin, testosterone, progesterone and oestrogen.
      ADH
      Lack of water is detected by the hypothalamus in the brain, it causes the pituitary gland to produce Anti-diuretic hormone, or ADH. This makes the kidneys to reabsorb more water- so less is lost from the body.

      Adrenaline
      Produced in the adrenal glands in stressful situations. Heart rate quickens to increase the flow of blood to muscles- this means that they can respire more (as there is more oxygen available) to provide energy if you need to 'fight or flee'.

      Insulin
      Produced in the pancreas when there is too much glucose in the blood. It stimulates cells to convert the glucose into glycogen which is a from that can be stored. This means that you always have the right amount of glucose in your blood.

      Testosterone
      Produced in ovaries in girls and testicles in boys. Plays a key role in puberty, developing sex organs and inspiring hair growth.

      Progesterone
      Produced in the ovaries it maintains the lining ready for pregnancy, and continues to do so if the egg is fertilised.

      Oestrogen
      Produced in the ovaries, it is controls other hormones to regulate the menstrual cycle. It stops the production of FSH and starts the production of LH.

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  5. The Biology Syllabus has changed.... New Syllabus Blog:

    http://igcse-biology-2017.blogspot.hk

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  6. more at

    http://igcse-biology-notes.blogspot.hk/2017/06/289-describe-role-of-skin-in.html

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