What is Homeostasis | Meaning, Function - Physiological & Biological, and Feedback system; Example -

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Homeostasis :-

Homeostasis is the ability of the body or a cell to maintain a condition of equilibrium within its internal environment when dealing with external changes.
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Homeostasis refers to the maintenance of constant internal environment of the body Homeostasis is the state of steady internal, physical, and chemical conditions maintained by living systems.
Homeostasis is a dynamic condition.
The condition such as water balance, body temperature, blood sugar levels and blood pH need to be maintained constant in order to set the different physiological processes to occur.

The body undergoes constant change as a result of which there is a shift in the equilibrium.
In most cases the disruption of homeostasis is mild and temporary, and the response of body cells quickly restores balance in the internal environment.
It may also occur due to psychological stress.

A feedback system in cycle of events in which the status of body condition is monitored evaluated, altered, remonitored, re-evaluated and so on.
Each monitored variable, such as body temperature, blood pressure, or blood glucose level, is termed controlled condition.
Any disruption that changes controlled condition is called stimulus.

Whenever any change occurs, system receives and reacted to two types of feedback;

Negative feedback is the one to which the system reacts in such a way as to arrest the change or reverse the direction of change.
After receiving a message, effectors send negative feedback signals back to the system.
Now, the system stabilizes its own function and makes an attempt to maintain homeostasis.
Many homeostasis mechanisms in the body function through negative feedback.

For example;

Thyroid stimulating hormone (TSH) released from pituitary gland stimulates thyroid gland to secrete thyroxine.
- When thyroxine level increases in blood, it inhibits the secretion of TSH from so that, the secretion of thyroxin from thyroid gland decreases.

It is the one to which the system reacts in such a way as to increase the intensity of the change in the same direction.
One of the positive feedback occurs during the clotting.
Blood clotting is necessary to arrest bleeding during injury and it occurs in three stages. The three stages are;
- 1. Formation of prothrombin activator
- 2. Conversion of prothrombin into thrombin
- 3. Conversion of fibrinogen into fibrin.

A receptor is a body structure that monitors change in controlled condition and sends input to control centre.
The input is present in the from of nerve impulses or chemical signals.

It is the brain in which sets the range of values within which controlled condition should be maintained, it evaluates the input receives from receptors and generates output commands.
Nerve impulses from receptors and generates output commands.
Nerve impulses, hormones or other chemical signals are the various forms of nerve impulses through which output occurs.

An effector is a body structure that receives output from the control centre and produces a response or that changes the controlled condition.
Every organ or tissue in the body can behave as an effector.