Question

How does the principle of homeostasis relate to endocrine function? Provide a specific example of how hormones are regulated through the use of feedback systems.

Answer 1

Many endocrine glands are linked to neural control centres by homeostatic feedback mechanisms

The two types of feedback mechanisms are positive feedback and negative feedback

Negative feedback decreases the deviation from an ideal normal value and is important in maintaining homeostasis. Most endocrine glands are under the control of negative feedback mechanisms

As example of negative feedback mechanism is the regulation of blood calcium level

The parathyroid glands secrete the parathyroid harmone which regulate blood calcium level,if calcium decreases, the parathyroid harmone secrete more parathyroid harmone which stimulates release of calcium from bones and increases absorption of calcium from collecting tubules of kidney.Conversely,if blood calcium increases too much the parathyroid glands decreases parathyroid harmone secretion.

Both responses are examples of negative feedback because in both the cases the effects are opposite to the stimulus

An example of positive feedback mechanism is found in the child birth

The harmone stimulates and enhances the labor contractions. As the baby moves towards the vegina the pressure receptors sends signals to the brain to produce oxytocin, Oxytocin travels through the blood stream and stimulating the muscles to contract stronger (than normal value).The contractions intensify until the baby comes out via the birth canal

It is the effect of positive to the stimulus, Ao it is the response of positive feedback