Notes

← Back to home

A collection of fragments of understanding in the pursuit of deeper questions.

Limb Position

How is Limb Position Maintained?

  • Involuntary Movement (i.e., posture): continual contraction and relaxation of the muscles in our feet and calves.
  • Voluntary Movement: stretch of the intrafusal fiber causes contraction of the extrafusal fiber via alpha motor neuron. Keeping the movement at this position requires a direct signal from the brain.

Automatic Maintenance of Limb Position

image89 image90

How is the position maintained with an external force? The intrafusal motor neuron (Gamma) signals the change, which is accounted by the Extrafusal Motor Neuron (Alpha) by increased firing.