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Regulation (Homeostasis)

the control centre. Examples of effectors The output sends the response instructions
include: the sweat glands, blood vessels, from the control centre to the effector.
and muscles. The control centre of the For example, if the temperature needs to
homeostatic control is the brain, particularly be lowered, the hypothalamus will send
the hypothalamus. The control centre the information to the effector for the
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analyses the information from the receptor response. Compensatory response is the
and determines the appropriate response to action of the effector that will counteract
the change or stimulus. the stimulus and bring the variable back to
its normal range.

Input - Stimulus

Detector

Regulator

Effector

Output - Response

Figure 7.1: Components of the homeostatic control mechanism

Feedback mechanism for homeostatic Two forms of feedback, namely negative
control and positive feedback are recognised.

Task 7.2 Negative feedback
Search from the internet sources the A negative feedback occurs in a situation
simulation videos/documentaries on where the disturbance in a system sets
feedback mechanisms in the human body. in motion a sequence of events which
tends to restore the system to its original
Any change from the set point activates state. A negative feedback in homeostatic
the control system to initiate a sequence control mechanism keeps a variable,
of events so as to either restore conditions such as the blood glucose level close to a
towards their normal state, or to make the particular value or set point (Figure 7.2).
system deviate further. Feedback requires A change in the state of an internal factor
the action of the system to be related to in the body causes effectors to restore the
a reference point or set-point (optimum internal environment to its original state.
level) of the variable being controlled.

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