Motor Neurons

gamma Motor Neurons

Gamma motor neurons keep the muscle spindle sensitive so your nervous system can detect changes in muscle length and stretch.

Muscle Spindle

detects how much a muscle is being stretched/lengthened

Alpha Motor Neuron

make the actual muscle fibers contract

Beta Motor Neuron

help with both muscle contraction and maintaining the muscle spindle's sensitivity.

Intrafusal Fibers

Inside the muscle fiber: sensory role → detect muscle stretch

Extrafusal Fibers

Outside of the muscle fiber: actual muscle contraction → produce movement

Gamma Fiber

Intrafusal

Beta Fiber

Intrafusal and Extrafusal

Alpha fiber

Extrafusal

Muscle Spindle Fiber

Intrafusal