Describe the mechanisms of control feedback for the endocrin

Describe the mechanisms of control (feedback) for the endocrine system. Note the 2 basic mechanisms of feedback control. Draw or describe these general mechanisms and give one specific example of each. (At least 2 paragraphs, maybe 4-6 explain an example of each).

Solution

Feedback mechanisms play an important role in maintenance of homeostatic conditions of the body. Various components such as receptors, control center and effectors are involved in this. They are of two types namely,

Positive feedback mechanism

Negative feedback mechanism

If the release of one hormone is further triggered by its release, then it is called as positive feedback mechanism.

Eg: Release of oxytocin during labour pains is the best example of positive feedback regulation. In this, the initial release of oxytocin triggers uterine contraction.

Increased uterine contractions further stimulate the posterior pituitary to release more oxytocin, this positive loop control results in abnormal raise of oxytocin levels that are very essential during child birth. After delivery, the uterine muscles relax, allowing the oxytocin levels to decrease. This is an example of positive feedback regulation.

If the release of hormone inhibits the further release of the same, and thus inhibiting the abnormal increase in a particular compound, then it is called as negative feedback regulation.

Calcitonin is secreted by the parafollicular cells of the thyroid gland and it is involved in the metabolism of calcium and phosphorus, calcitonin has opposite effects to that of PTH.

High plasma concentrations of calcium stimulate the calcitonin release. Calcitonin decreases the blood calcium levels, so that the stimulus triggering its release also suppress. This is a negative feedback regulation.