Endocrine Regulatory Mechanisms - MCAT Biological and Biochemical Foundations of Living Systems

Card 1 of 48

0
Didn't Know
Knew It
0
1 of 2019 left
Question

Which of the following are examples of positive feedback mechanisms in the body?

I. Fever during illness

II. Loss of bone mass in osteoporosis

III. Contraction during childbirth

Tap to reveal answer

Answer

Positive feedback describes an event in which a pathway generates a response that further triggers the pathway, increasing the pathway effects. In contrast, negative feedback occurs when a pathway generates a response to inhibit the pathway origin, diminishing the pathway effects. Negative feedback is a common control mechanisms in the body to maintain homeostasis, while positive feedback is inherently designed to disrupt homeostasis.

Fever during illness is enhanced via a positive feedback system that only ends once the illness begins to alleviate. Similarly, contractions during labor will intensify via positive feedback oxytocin stimulation until the child is born. Osteoporosis is caused by an imbalance in the negative feedback system that controls blood calcium. This imbalance simply means that bone is lost more than it is gained, and is still an example of negative feedback.

← Didn't Know|Knew It →