Flashcards · Biology · Homeostasis
Temperature Control and the Skin
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At what temperature is the body kept?
About 37 °C.
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Where are temperature receptors found?
In the skin and in the hypothalamus.
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What is the coordination centre for temperature control?
The hypothalamus in the brain.
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Name the effectors for temperature control.
Sweat glands, muscles in the walls of blood vessels, hair erector muscles and skeletal muscles.
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How does sweating cool the body?
Sweat evaporates and takes heat from the skin.
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What is vasodilation?
The widening of blood vessels near the surface of the skin.
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How does vasodilation help when too hot?
More blood near the surface, so more heat is lost.
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What is vasoconstriction?
The narrowing of blood vessels near the surface of the skin.
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How does vasoconstriction help when too cold?
Less blood near the surface, so less heat is lost.
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How does shivering warm the body?
Muscle respiration releases heat.
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What happens to hairs when it is cold?
They stand up, trapping an insulating layer of air.
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What does the fat layer do?
It insulates the body.
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Why does the skin look red when hot?
Blood vessels widen and more blood flows near the surface.
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Why does the skin look pale when cold?
Blood vessels narrow, so less blood flows near the surface.
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Why is temperature control an example of negative feedback?
A change causes a response that reverses the change.
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Name the part of the skin marked X and say what it does when it is hot. The sweat gland. It releases more sweat, which evaporates from the skin and cools the body.
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Label the skin. 
Epidermis, hair, hair erector muscle, sweat gland, sweat duct, blood vessel, temperature receptor and fat layer.
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Describe the body's responses to being too hot and too cold. 
Too hot: more sweat, blood vessels widen, hairs lie flat. Too cold: shivering, blood vessels narrow, hairs stand up.