Reflex For patellar

Reflex Step 1 

1. Stimulus

• Tap on the patellar tendon (usually with a reflex hammer).

Step 2

2. Location of Sensory Receptors

• Muscle spindle fibers located within the quadriceps femoris muscle.

  • These detect the sudden stretch caused by the tendon tap.

Step 3

3. Functional Neuron Type to Spinal Cord

• Afferent neuron (sensory neuron).

  • Specifically: Ia sensory fiber from the muscle spindle.

  • Travels through the dorsal root into the spinal cord.

Step 4

4. Functional Neuron Type Away From Spinal Cord

• Efferent neuron (motor neuron).

  • Specifically: Alpha motor neuron.

  • Leaves through the ventral root back to the quadriceps.

Step 5

5. Effector

• Quadriceps femoris muscle.

Step 6 

6. Response

• Extension of the leg at the knee (the classic “kick”).