#example of reflex arc?

An example of a reflex arc is the knee-jerk reflex. When the doctor taps the patellar tendon just below the kneecap with a reflex hammer, the sensory neurons in the muscle spindle detect the stretch and send a signal to the spinal cord. The spinal cord then sends a signal back to the muscle to contract, causing the leg to kick out involuntarily. This entire process occurs without conscious thought and is a protective mechanism to prevent injury.