Question

Why is positive feedback much less common than negative feedback in body systems?

Answer 1

Homeostasis

Feedback mechanism form back bone of homeostasis. Homeostasis refers to the equilibrium condition of the body that  helps to maintain the internal environment relatively constant. Feedback mechanism are crucial  for maintaining normal form and function of Endocrine system.

Endocrine system

Endocrine system constitutes different glands and their synthesized hormonal products  which are released into the blood stream to affect the target organs or tissues located at a different part of the body. Secretion and inhibition of these hormones are important for maintaining normal form and function. This is brought about by Feedback loop or Feed back mechanism.

Feedback mechanisam

Feedback can be either positive feedback or negative feedback.

• Positive feedback mainly accelerates or increases the production and concentration of hormones leading to an increased activity  of a particular system. This causes further movement away from the homeostatic condition. Uncontrolled positive feedback can cause dangerous effects.
• Negative feedback on other hand decelerates or decline the activity by decreasing the hormonal production. This helps to shift the body back to the state of hemostasis.
• Both these mechanism are important to control and bring about different changes in the body.

Example

1. positive feedback: release of hormone oxytocin to bring about contraction during labor. Platelet aggrigation during clot formation.
2. negative feedback: regulation of blood pressure .

As we can see negative feedback mechanism helps the body to shift towards the equilibrium condition and hence it will be more common in the body than positive feedback which will further takes body away from homeostasis.