Question

The leg extends at the knee.

Sensory neurons conduct the action potentials to the spinal cord.
Motor neurons are stimulated and generate an action potential.
Sensory neurons synapse with motor neurons in the spinal cord.
The AP travels to the quadriceps femoris and causes it to contract.
Sensory receptors in the muscle detect the stretch of the tendon and muscles."
A) 1, 2, 3, 4, 5, 6
B) 6, 5, 4, 3, 2, 1
C) 2, 4, 3, 1, 6, 5
D) 4, 3, 2, 5, 1, 6

Answer 1

The correct order of the events in a reflex arc when the leg extends at the knee is option C: 2, 4, 3, 1, 6, 5, starting with the sensory neurons conducting action potentials to the spinal cord and ending with the leg's extension.

Step-by-step explanation:

The sequential process described in the student's question pertains to a reflex arc occurring in the body, specifically when the leg extends at the knee. To correctly order these events, we should start from the initial stimulus detection by sensory neurons and proceed through the neuron pathway leading to muscle contraction. The correct order is: (2) Sensory neurons conduct the action potentials to the spinal cord, (4) Sensory neurons synapse with motor neurons in the spinal cord, (3) Motor neurons are stimulated and generate an action potential, (1) The action potential (AP) travels to the quadriceps femoris and causes it to contract, (6) Sensory receptors in the muscle detect the stretch of the tendon and muscles, and (5) Leg extends at the knee. Therefore, the correct sequence for the processes described is option C: 2, 4, 3, 1, 6, 5.