Question

Which one is a positive feedback mechanism?
A)Sexual stimulation
B)Allosteric inhibition
C)Blood pressure
D)Perspiration

Answer 1

Hint: The feedback mechanism performs the functions of a regulator that aids and helps in maintaining the balance of hormones in the body. It keeps a check on the amount of the hormone released and keeps the amount of hormone released to be constant.

Complete answer:
The hormone feedback mechanism is defined as the mechanism that is used to maintain the hormone balance in the blood / body. The increase or decrease in the concentration of that hormone can sometimes stimulate and increase the secretion of that hormone or inhibit the secretion of the hormone. It’s called feedback.
Feedback mechanisms control the most hormones that are secreted by endocrine glands. A feedback mechanism is a loop with the help of which a product feeds to regulate its own production. There may be two types of feedback mechanism, that are named as positive feedback and negative feedback. Positive feedback stimulates and enhances the secretion and/or production of the hormone. On the other hand, the negative feedback prevents and inhibits the hormone from being secreted. Most mechanisms for hormone feedback constitute negative loops. Negative feedback helps and maintains the hormone concentration within a limited range.

Now let us find solution from given options:
Sexual stimulation : Sex hormone are secreted by testes when hormones are secreted in access it gives response to stop them thus produces negative feedback
Allosteric inhibition : Allosteric inhibition is also termed as the feedback inhibition due to the reason in feedback inhibition, the end products of a reaction are known to bind to the allosteric site of the enzyme leading to the inactivation of enzyme thereby it helps to generate a lesser amount of products. So it is a kind of positive mechanism
Blood pressure : When blood pressure rises the blood vessels give a signal to the brain and then the brain gives a signal to the heart, Thus heart rate is brought down and helps in providing back the blood pressure to the normal level So produces a negative mechanism.
Perspiration : The changes in the temperature is recognized by the hypothalamus of a human which responds accordingly. if the temperature of the body is hot then the body will sweat to cool down by a process called evaporation and when the temperature drops that is body becomes cool and body shivers to bring up the temperature so it shows negative feedback mechanism.

Hence, the correct answer is option (B)

Note: The hormone feedback system is defined as the process by which the hormone balance in the blood / body is maintained. A change in the concentration of that hormone may either stimulate and increase or inhibit and stop the secretion of the hormone.