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Communication Homeostasis

Learning objective(s):

Define the terms negative feedback , positive feedback and homeostasis
Explain the principles of homeostasis in terms of receptors, effectors and negative


Establish the ideal conditions required for cells to work correctly ­ maintaining the
constant internal environment despite changes to the external environment…

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Organs involved in homeostasis:

Hypothalamus ­ receptors to monitor blood temperature and water content and then
sends nerve impulses to the skin and to the pituitary gland ; also monitors CO2 levels
Lungs ­ removes carbon dioxide and prevents hypercapnia
Pituitary gland ­ produces many vital hormones , including…

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Negative feedback is a process that brings about a reversal of any change in conditions . It ensures
that an optimum steady state can be maintained , as the internal environment is returned to its
original set of conditions after any change .

For negative feedback to work effectively there…

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and slows down the enzymecontrolled reactions even more, so that the body temperature spirals

Enzyme action and temperature regulation
As core body temperature rises the increase will affect the activity of enzymes . This can lead to
heat exhaustion and even death . When temperature increases, enzymes gain kinetic…

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Endotherms include birds and mammals ­ their core body temperature is kept nearly constant by
thermal homeostasis , largely independent of the external temperature .


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