2007-05-17 15:07:55 · 4 answers · asked by pinkrose 1 in Science & Mathematics ➔ Biology
Positive and negative feedback mechanisms are two control systems in the body that help maintain homeostasis. Most control systems in the body act by negative feedback where something in either low concentration or high concentration (ex, carbon dioxide) which, in turn, initiates a stimulus (increasing pulmonary ventilation). Positive feedback (AKA a "vicious cycle") is not as common and is a mechanism that leads to instability and often death where the initiating stimulus causes more of the same (ex, continued blood loss with weakening of the heart).
2007-05-17 15:29:21 · answer #1 · answered by nancynurse 2 · 0⤊ 0⤋
A feedback mechanism provides the basic means of communication among cells.
There is positive feedback which "requests" more.
And there is the negative feedback which "requests" less or more likely to stop doing something.
Think of positive as a green light and negative as a red light.
2007-05-17 19:32:41 · answer #2 · answered by seriously 2 · 0⤊ 0⤋
A feedback mechanism is a specific response to a stimulus. Wikipedia says, " Feedback is the signal that is looped back to control a system within itself. This loop is called the feedback loop. A control system usually has input and output to the system; when the output of the system is fed back into the system as part of its input, it is called the "feedback.""
Generally, there are two types of feedback cycles: negative and positive. In negative feedback the response to a stimulus tends to decrease or eliminate the stimulus. In positive feedback, the response to a stimulus tends to increase the stimulus.
An example of negative feedback is in the control of blood sugar. High levels of sugar in the blood (stimulus) cause the release of the hormone insulin (response). Insulin causes the uptake of glucose from the blood by liver and skeletal muscle, thus decreasing the level of sugar in the An example of positive feedback is in the suckling response in nursing mothers. A baby suckling (stimulus) causes the release of the hormone oxytocin (response). The oxytocin causes the "milk let-down reflex" in the mother. So, the baby gets milk, and suckles more, causing more release of oxytocin, etc.
2007-05-17 15:51:27 · answer #3 · answered by kt 7 · 0⤊ 1⤋
A feedback mechanism is something that links the output of a system to its input.
2007-05-17 15:17:54 · answer #4 · answered by extton 5 · 0⤊ 1⤋