Question

Which of the following is an example of a negative feedback loop?

During lactation, as an infant suckles, it stimulates the release of prolactin in the mother. Prolactin causes more milk to be produced for the infant to suckle. This continues until the infant stops breast feeding.

Baroreceptors in the arteries send a signal to the brain that the blood pressure is low. The brain sends a chemical signal to the heart to increase its rate of pumping. This continues until the baroreceptors sense a normal blood pressure.

During blood clotting, chemicals are secreted by wounded tissues that recruit platelets to the area. As the platelets arrive, they secrete more of the same chemicals, recruiting more platelets to the wound. This continues until the wound is clotted.

During childbirth, pressure on the cervix stimulates the release of oxytocin. This causes contractions, and therefore puts more pressure on the cervix. This cycle continues until the baby is born.

Answer 1

The baroreceptors sensing low blood pressure and initiating a response to normalize it is an example of a negative feedback loop.

Step-by-step explanation:

An example of a negative feedback loop is the process where baroreceptors in the arteries sense low blood pressure and send a signal to the brain. The brain responds by sending a chemical signal to the heart to increase its rate of pumping. This action raises the blood pressure to normal levels, and once normal blood pressure is sensed by the baroreceptors, the heart's pumping rate is adjusted to maintain the normal pressure. This feedback system works to reverse the direction of the initial stimulus (low blood pressure), making it a classic negative feedback mechanism.

Answer 2

The correct answer is: Baroreceptors in the arteries send a signal to the brain that the blood pressure is low. The brain sends a chemical signal to the heart to increase its rate of pumping. This continues until the baroreceptors sense a normal blood pressure.

A negative feedback loop occurs in the body when something in the body has decreased in function, which could mean high or low, for example blood sugar, body temperature or in this in this case blood pressure. It then creates a feedback loop to tell that part of the body to regulate itself and return the body to a state of homeostasis (which is your optimal internal state). In a negative feedback loop the response of the regulating mechanism is opposite to the output of the event. So if blood pressure is low the negative feedback loop will tell the body to increase the pressure.

A positive feedback will result in more of a product: more prolactin, more contractions, or more clotting platelets.