Question

In a negative feedback mechanism, what does negative means ?

Answer 1

• Negative Feed back mechanism is where the end product itself inhibits its synthesis or production .
• Suppose consider thyroid hormone release from thyroid gland.
• When there is low concentration of thyroid hormone in the blood , the hypothalamus in the brain senses it.
• It releases a factor called thyoid releasing hormone (TRH) which inturn activates pitutary to release thyroid stimulating hormone(TSH).
• This TSH stimulates thyroid gland to synthesise thyroid hormone.
• This process is called positive feed bac mechanism.
• When the levels of thyroid hormone reaches the normal concentration in blood, the thyroid hormone itself inhibits its production from hypothalamus and pitutary directly.
• Because of this inhibition TRH and TSH production is stopped and thus ultimately thyroid hormone synthesis is stopped.
• This is called as negative feed back mechanism.
• Negative here refers to inhibition .
• Positive means production .