Question

Negative and positive feedback systems both have their roles in physiology. Compare and contrast these two types of feedback systems and provide a biological example of each, illustrating how it works. Which, if any, of these two types of feedback are involved in the maintenance of homeostasis? Explain.

Answer 1

Negative feedback system- it is a well regulated body's metabolism system in which output of any process is decreased or slow down when requirements in the body of the product varies. For changing the output quantity to lesser levels, the input of the system or factors involved in producing output us altered. As negative means opposite, so the growth ( in terms of production) is decreased.

For eg - Growth factor is released by anterior lobe of pituitary. It is required for growth of cellular tissue and organs, differentiation etc. But when the amount of growth hormone is more than sufficient, the body, a factor called IGF-1 is released from the body, which gives negative signal to anterior pituitary to stop releasing further more GH.

Positive feedback system- it is also the body's mechanism to enhance its productivity of certain factors or output by increasing the efficiency or result of the amount of output produced. For the increament, again a positive tranfer of signals are sent towards the target organs. For eg - Release of oxytocin during parturition is a kind of positive feedback system. Due to muscular contractions in the uterus , pressure receptors get activated and sends signal to posterior pituitary to release oxytocin as it helps in increasing the contractions which aid in parturition.

Yes, negative feedback system is involved in the maintenance of homeostasis because negative feedback system are stable and keeps a check on maintaining homeostasis. This is like whenever a positive feedback is there, it amplify the result or output in one particular direction and hence always increases the course, while negative feedback helps in maintaining a constant stable conditions inside body to prevent any major fluctuations from the normal body's physiological levels. So counter action of negative feedback helps in maintaining homeostasis.

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