negative feedback

[Tamaroshka]

Can anyone explain for me how negative feedback mechanisms operate to regulate blood volume and urine output??

[mith]

you pee when you have too much blood

[Tamaroshka]

this question was in my examand i didnt know how to answer it ,,,, so if i were in the exam i should write that answer!!? thanks anyways

[jwalin]

basically what happens is that the brain senses the high amounts of water in blood and as a result gives an output that will result in reduction of the amount of water in blood (that is why it is called negative feedback). this output is by stopping the release of antidiuretic hormone (ADH) and an increase in the urine output

[jwalin]

ever wondered of an example of a positive response?

[jwalin]

an example would be
if the air is full of CO2 then the CO2 in the blood will increase. this will lead to a signal to increase the rate of respiration and as a result the amount of CO2 in blood will increase

[jwalin]

positive feedback never helps maintain balance.

[Tamaroshka]

yeah thanks alot i just got it know

[JackBean]

jwalin: first study and than speak There are plenty of positive feedbacks E.g. in calcium sensing, the small amount of calcium released causes more and more release by activation of the canal

[jwalin]

that is rude
never mind.
but i never said that there are no positive feedbacks.
gave an example of the CO2 one as it helps understand better.

[jwalin]

could have given examples of the clotting system or the contraction during childbirth or eostrogen release during the follicle phase in menstrual cycle.

[jwalin]

and many more.
but anyways positive feedback never helps maintain constant balance of the parameter it controls.