Mobombi had completed about a quarter of the distance in the marathon in which he was a participant. Suddenly, he stumbled and fell. Despite feeling a sharp pain initially, he got up and continued to run until he completed the race

Upon crossing the finish line he fell down writhing in pain. When checked out, it was discovered that Mobombi had broken his leg. He was able to run the remainder of the marathon relatively pain free due to the release of
A) enzymes.
B) amino acids.
C) monoamines.
D) endorphins.

Answer: D
Rationale: Endorphins are produced by the pituitary gland and the hypothalamus and function to reduce pain and induce feelings of pleasure. Endorphins are released into the blood stream during events such as strenuous exercise, sexual activity, or injury.