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    What's the difference between Negative feedback and Thermoregulation ?
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    (Original post by Adorable98)
    What's the difference between Negative feedback and Thermoregulation ?
    Negative feedback is a mechanism whereby any change in the internal environment is opposed so as to maintain a constant internal environment. Negative feedback allows us to maintain a constant internal environment (homeostasis).

    Thermoregulation is a mechanism that allows core body temperature to stay within a narrow limit of the set point, allowing us to maintain a relatively constant internal body temeprature. Thermoregulation uses negative feedback to do this; when body temperature falls, thermoreceptors in the peripheral nervous system detect this change and send a signal to the hypothalamus which in turn sends a signal to arterioles which supply blood to the skin to vasoconstrict which reduces blood flow to the skin (and hence heat loss to the surroundings by convection and radiation). The hypothalamus also sends signals to erector muscles in the skin which are attached to the base of hair follicles causing them to contract and causing the hairs to stand on end. These hairs trap small pockets of air which reduces heat loss by conduction, as air is a poor thermal conductor, and convection. The hypothalamus also sends signals to skeletal muscles causing them to contract (shivering) which increases respiration and therefore heat production in muscle cells. If exposed to a cold environment for a long time (a few days), thyrotropin-releasing hormone (TRH) is released by the hypothalamus which causes the anterior pituitary gland to release thyrotropin, a hormone which travels in the bloodstream to the thyroid where it causes the thyroid to release thyroxine and triiodothyronine into the blood which increase the metabolic rate and hence heat production in body cells.

    When body temperature is too high, peripheral thermoreceptors detect the rise in temperature and send signals to the hypothalamus which turns on the body's cooling mechanisms. The arterioles supplying blood to the skin dilate, increasing blood flow to the skin which in turn increases heat loss. The hypothalamus also sends signals to the sweat glands, causing an increase in sweat production which in turn increases heat loss (as water has a high specific latent heat of vaporisation and a high specific heat capacity). The hairs also lie flat.
 
 
 
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Updated: March 20, 2016
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