A self-regulating mechanism that controls certain body processes such as hormone and enzyme production. If, for example, levels of a hormone are too high, output of any substance
that stimulates the hormone’s release is inhibited; the result is reduced hormone production (negative feedback). The reverse process,(positive feedback) restores the balance if the level of hormone becomes too low.
n. (in physiology) the coupling of the output of a process to the input. Feedback mechanisms are important in regulating many physiological processes; for example, the production of hormones and neurotransmitters. In negative feedback, a rise in the output of a substance will inhibit a further increase in its production, either directly or indirectly (see negative feedback loop). In positive feedback, a rise in the output of a substance is associated with an increase in the output of another substance, either directly or indirectly.
Many glands which produce HORMONES are in?uenced by other hormones, particularly those secreted by the HYPOTHALAMUS (a controlling centre in the brain) and the PITUITARY GLAND. If the amount of hormone produced by a gland rises, negative feedback mechanisms operate by instructing the pituitary gland, via the hypothalamus, to produce less of the stimulating hormones. This cuts activity in the target gland. Should the amount of hormone produced fall, the feedback mechanism weakens with the result that the output of stimulating hormones increases.... feedback mechanism
a physiological loop for the control of hormone production by a gland. High levels of a circulating hormone act to reduce production of the releasing factors triggering its own production, i.e. they have a negative *feedback on these trigger factors. As circulating levels of the hormone fall, the negative feedback is reduced and the releasing factor starts to be produced again, allowing the hormone level to rise again.... negative feedback loop
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