Question

Why do most control systems of the body operate by negative feedback rather than positive feedback?

Answer 1

cause its easy to to respond to one feedback. think like this if you send massage to ur friends and ask them to replay if they get massage(positive feedback) then you need to go through lot of responses and find out who didnt get instead if you ask to give you respons (negative feedback) if they didnt get massage then your work get reduce
so its increase your accuracy and also decrease your work

Answer 2

because postitve feedback was already workin , so there must be somethin to stop it for exaple insulin works after having sugar too much insulin cause low blood sugar there must be negative feedback to reduce insulin and increase glucagon .

Answer 3

https://www.inkling.com/read/guyton-hall-textbook-of-medical-physiology-12th/chapter-1/control-systems-of-the-body
What is negative feedback?

Negative feedback is a system by which internal conditions are kept within set limits. For example your home thermostat has a thermometer which detects when the temperature of your home drops below room temperature which triggers a response, the heating is turned on. When your home is brought back to room temperature, the response is turned off to prevent the temperature getting too high.

In living organisms examples include: solute concentration of the blood/tissue fluid (which affects the water potential of cells and the cytoplasmic reactions that can occur), internal body temperature (must be kept close to the optimal operating temperature of metabolic enzymes within the cells), changes in pH etc.

What is a good example of a negative feedback loop?
Not sure what they mean by that but...
A good example of a positive feedback loop is the increased production of insulin by our pancreas. After a meal we may have heightened blood sugar levels. The endocrine system triggers insulin production in the pancreas to counteract this rise and return our blood sugar levels back to normal. Once normality has been reached the endocrine system signals our pancreas to cease the production and release of insulin.
Actually, that is an example of a negative feedback loop. Negative feedback loops negate an action, while positive feedback loops encourage it. An example of a Positive feedback loop is childbirth, the body increases the amount of oxytocin in the blood to encourage contractions in order to birth the baby.

Answer 4

I know the mechanism, but the question is WHY.

Answer 5

Negative feedback in homeostasis describes a process by which bodily systems maintain their normal environments or states. Homeostasis describes the body's overall regulation of its internal systems. When changes in a state such as body temperature occur, negative feedback responses are triggered to bring the temperature back to its normal point. For example, if the body becomes too hot, sweating occurs to cool it. If the body becomes too cold, shivering is one response that helps to warm it up.

The correct (i.e. within an acceptable range) concentration of hormones must be maintained because hormones have powerful effects on the body. Feedback systems are an ideal means of controlling hormone levels because they involve constant monitoring and making adjustments to keep hormone levels stable. That is particularly important in the case of hormone levels because:
Hormones can affect target organs at low concentrations so even a small quantity can sometimes be too much.
The length of time during which hormones remain active is limited so more hormones must be secreted as necessary to replace those that are inactivated*.
http://www.authorstream.com/Presentation/Dharann-1340981-8-negative-feedback-systems/

Answer 6

Positive feedback cycles are very sensitive to amplification and becoming uncontrolled unstable reactions. With associated toxicity effects. For this reason they are uncommon in biologic systems - but they tend to drive or regulate the absolutely essential biologic processes, the ones the cells would immediately die without.

Whereas negative feedback loops elegantly inhibit themselves.

In practice, positive feedback loops are rarely (I open myself to counter example, but I would say never) the only regulators of any given process -- any process that is driven by a positive feedback loop is also always down regulated by usually more than one negative feedback loop.

For example, read up on hypoxia inducible factor.