Nervous Control of Temperature


 
 
Concept Explanation
 

Nervous Control of Temperature

  • Body temperature is also controlled by the nervous system and this is a more immediate response. When the hypothalamus detects a drop in temperature, it sends nerve impulses to muscle groups around vital organs such as the heart and lungs. Small shaking movements begin in these muscles. Eventually, the shaking movements extend to the large muscles of the arms and legs, and you begin to shiver. Shivering increases the activity of muscle cells, producing heat and raising body temperature. This is the body's way of creating warmth by using energy.
  • Another aspect of nervous control is the process that reduces blood flow to your skin when you are cold. The sympathetic nervous system causes a narrowing of the blood vessels near the surface of the skin. This reduces blood flow and therefore heat flow to the skin. If the external temperature is very low, the blood flow to the fingers, toes, nose and ears is reduced further and you can lose feeling in them. This causes your toes and fingers to go numb.
  • When the hypothalamus detects a rise in body temperature, nerve messages are sent to the sweat glands and blood vessels. Blood vessels close to the skin dilate. This change allows more blood and the heat it carries to reach the skin surface. The extra blood near the surface makes your skin red.
  • The message from the hypothalamus causes the sweat glands to produce more sweat. Heat from your body causes the sweat to evaporate. The rate at which  heat is lost by evaporation depends on the difference in temperature between the body and the surrounding air, and the relative humidity of the air.
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    Sample Questions
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    Question : 1

    Blood vessels close to skin dilates when _________________

    Right Option : A
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    Question : 2

    Which part of the nervous system help our body to deal with cold condition ?

    Right Option : A
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    Question : 3

    When the hypothalamus detects a drop in temperature, it sends nerve impulses to ________ around vital organs such as the heart and lungs.

    Right Option : C
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