Control of Endocrine Glands

 Control of Endocrine Glands

Each hormone released by the endocrine glands has its own mechanism that controls the level in plasma. Most endocrine gland secretions are controlled by a negative feedback mechanism (see Figure 6.2A).For example, the secretion of hormones by the en-docrine gland is triggered by a stimulus. The hor- mone secreted reduces the activity of the stimulus and this, in turn, reduces the secretion of the hor-mone. This type of control is similar to the reflexes in the nervous system. Sometimes, like a polysynaptic reflex, there are many steps involved in the control of endocrine secretion.


Rarely, secretions are controlled by a positive feed-back mechanism (see Figure 6.2B) in which the hor-mone secreted increases the activity of the stimulus.


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