What is homeostasis| Its Mechanism, Positive & Negative Feed Backs

It is a state of equilibrium or balance of the internal environment of the body.

It is a non-stop and dynamic process which tries to keep the body normal at all the possible conditions.

Since a living body is subjected to many external and internal stresses or simulations, the homeostasis will keep he body in normal.

It does so by a small change in the range of regular physiological conditions.

For example, normal blood pressure in humans is 120/80mmHg. If one is  anxious or even irritated, his blood pressure tends to rise to 140/90. Again when he cools down, it returns to normal. Similarly, many other body organs like heart, lungs also increase in their function.

This rise is meant to adopt the body to the excess demand like more oxygen, energy to cope up the situation.

This shift in balance is quite normal and is within few points. If it goes beyond, mostly it leads to disorders and even death based on the intensity and duration of deviation from homeostatic range.

Body systems like nervous system, endocrine system are involved in maintenance of homeostasis. This done through nerve stimulation or changes in hormonal levels.What is homeostasis

Other examples of disturbances and correction of homeostasis are

  1. Sweating when the body temperature rises due to heat in summer.
  2. Gushing and intense breathing to give excess oxygen while running or jogging.

In above conditions the body tries to keep the system normal. In conditions of failure to keep up the body temperature within the limits, the condition results to sunstroke. So the ability of the body to maintain homeostasis is essential to keep the body healthy.

This homeostasis is maintained due to 3 point of control as

  1. Receptors
  2. Control  center
  3. Effectors.

Receptors are the ones which first detect the change in homeostasis and send the signal to control center.

Control center provides a nervous stimuli or hormonal stimuli to bring desired homeostatic change.

Effectors carry out the signal provided by control center and induce the desired changes in body physiology.

This homeostasis control is by two systems viz.

  1. Positive feed back control.
  2. Negative feed back control.

Positive feed back system: This is a system of response where in the change in homeostasis is further enhanced to produce a desired effect.

Negative feed back system is one which reduces the slight change in ranges of homeostasis.


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