Question

When observing the patellar tendon reflex the leg moved without any conscious control. Trace the pathway of this reflex in terms of nerve terminology.

Answer 1

INTRODUCTION

Patellar tendon reflex is a type of monosynaptic reflex which does not involve any interneuron between afferent and efferent neuron.This reflex involves synapse in the spinal cord and there is no involvement of higher centres.​​​​​​

PATHWAY OF REFLEX:

1. When a hammer is striked at the patellar tendon,the information is perceived by sensory receptors on the tendon.
2. This sensory impulse is received by afferent (sensory) neuron .
3. Afferent neuron takes this impulse to the dorsal root ganglion of spinal cord ,where cell body of afferent neuron is present.
4. A synapse is formed between afterent and efferent (motor) neuron.
5. Motor neuron carries impulse to the quadriceps femoris muscle causing its contraction.This leads to extension of leg or the kicking movement.