Positive Feedback Mechanism

Positive Feedback Mechanism

Two type of feedback mechanism 

1. Positive feedback mechanism
2. Negative feedback mechanism

Here we discuss positive feedback mechanism

 

A positive feedback system is operating when an endocrine gland is stimulated to increase its rate of hormonal secretion (a positive effect) by a substance it caused to be produced. consequently, still more product forms and then more hormone is secreted.

Such a system is unstable in that it tends to produce extreme changes in conditions. Positive feedback system occur rarely in organism, however, one example of this type of system involves the sex hormone estrogen. This steroid is secreted by cells in the ovary in response to an anterior pituitary hormone (FSH). 

When estrogen is present in a certain blood concentration, it causes an increase in the secretion of some anterior pituitary hormones (including FSH), so that positive feedback exists for a short time