Question

explain how the knee jerk reflex works. include all the steps in the neural pathway.

Answer 1

Knee-jerk reflex, also called patellar reflex, results from sudden kicking movement of the lower leg in response to a sharp tap on the patellar tendon, which lies just below the kneecap. The sharp tap on the tendon slightly stretches the quadriceps, the complex of muscles at the front of the upper leg. In reaction these muscles contract, and the contraction tends to straighten the leg in a kicking motion. Exaggeration or absence of the reaction suggests that there may be damage to the central nervous system.

NEURAL PATHWAY

Reflex hammer stimulates stretch receptors of quadriceps femoris impulse travels via sensory and motor neurons reach cell body of sensory (Dorsal root ganglia)  and motor neurons in spinal cord interneurons   Knee-jerk reflex