Animation Assessment: The Knee-Jerk Reflex

How many synapses are involved in the contraction of the knee extensor muscles in the knee-jerk reflex? (a) 3 (b) 1 (c) 4 (d) 2

(b) 1

Stretch receptors in the knee extensor muscles stimulated by the tap of a physician's reflex hammer just below the knee cap directly triggers a nerve impulse in which answer choice? (a) an interneuron (b) a sensory neuron (c) a motor neuron (d) the patellar tendon

(b) a sensory neuron

Which answer choice is inhibited following a tap of a physician's reflex hammer just below the knee cap? (a) sensory neurons of the knee flexor muscles (b) motor neurons of the knee flexor muscles (c) motor neurons of the knee extensor muscles (d) sensory neurons of the knee extensor muscles

(b) motor neurons of the knee flexor muscles

How many synapses in total are involved in the knee-jerk reflex? (a) 2 (b) 1 (c) 3 (d) 4

(c) 3

The interneuron in the spinal cord triggers which answer choice? (a) a stimulatory stimulus that prevents contraction of the knee extensor muscles (b) a stimulatory stimulus that prevents contraction of the knee flexor muscles (c) an inhibitory stimulus that prevents contraction of the knee flexor muscles (d) an inhibitory stimulus that prevents contraction of the knee extensor muscles

(c) an inhibitory stimulus that prevents contraction of the knee flexor muscles