Answer:
So the reflex arc consists of these five steps in order-sensor, sensory neuron, control center, motor neuron, and muscle. It is important that reflexes occur without the need for thinking about them because there are things that happen to your body and forces acting in your body when you move that need to be responded to very quickly. A reflex action is an automatic (involuntary) and rapid response to a stimulus, which minimizes any damage to the body from potentially harmful conditions, such as touching something hot. Reflex actions are therefore essential to the survival of many organisms. The strength of the reflex response should be the same for both sides of the body.
If the response is weak, or absent, that may indicate damage to the nerves. The nerve roots that exit the spine to form the sciatic nerve are extremely sensitive. When the disc bulges that can easily irritate the nerve.
An abnormal response is slower and consists of extension of the great toe with fanning of the other toes and often knee and hip flexion. This reaction is of spinal reflex origin and indicates spinal dis-inhibition due to an upper motor neuron lesion.
Reflex study is important.