Neural Control And Coordination Question 32
Question: When a physician elicits the knee-jerk reflex by tapping deep tendons in the knee, the normal response is for the lower leg to swing forward. When this happens:
Options:
A) Muscles in the back of the lower leg are contracting but that in the front are relaxing.
B) Muscles in the front of the lower leg are contracting but that in the back are relaxing.
C) Muscles in the back of the thigh are contracting but that in the front are relaxing.
D) Muscles in the front of the thigh are contracting but that in the back are relaxing.
Show Answer
Answer:
Correct Answer: D
Solution:
[d] When any muscle contracts, its antagonist relaxes by rule.
The leg swings forward because the muscles in the front of the thigh (quadriceps femoris) contract.
At the same time the hamstrings in the back of the thigh, relax and are lengthened
BETA
