Refer to the figure showing the knee-jerk reflex. What is happening at point 1?
A) The motor neuron is bringing sensory information to the dorsal root in the spinal cord.
B) Inhibition from the afferent neuron is being transmitted to the interneuron and efferent neuron.
C) The efferent neuron is firing action potentials that are transmitted to the afferent neuron.
D) Action potentials fired by the stretch receptors are being transmitted to neurons in the spinal cord.
E) The sensory neuron is transmitting to the spinal cord information that will be transmitted to the motor neurons in the brain.

Question

Refer to the figure showing the knee-jerk reflex.  What is happening at point 1?
A) The motor neuron is bringing sensory information to the dorsal root in the spinal cord. 
B) Inhibition from the afferent neuron is being transmitted to the interneuron and efferent neuron. 
C) The efferent neuron is firing action potentials that are transmitted to the afferent neuron. 
D) Action potentials fired by the stretch receptors are being transmitted to neurons in the spinal cord. 
E) The sensory neuron is transmitting to the spinal cord information that will be transmitted to the motor neurons in the brain.

Quizplus · Accepted Answer

At point 1, action potentials fired by the stretch receptors are being transmitted to neurons in the spinal cord. This is because the sensory neuron is stimulated by the stretching of the muscle, which sends signals to the spinal cord where interneurons synapse with motor neurons causing contraction of the muscle. This signal transmission via action potentials is an electrochemical process that enables the communication between neurons in the spinal cord, ultimately leading to the reflex response of muscle contraction.

Refer to the Figure Showing the Knee-Jerk Reflex