ANAT 312 Lecture Notes - Lecture 1: Myocyte, Motor Neuron, Motor System
26 Nov 2016
School
Department
Course
Professor
Document Summary
The lateral motor system primarily targets the arms and legs and is driven by the red nucleus and corticospinal tract. Whereas the medial motor system is mostly involved in postural control and is driven by the brainstem and cerebral cortex. Produce a small, slow contraction with a small force output. Can generate force for an extremely long time: fast, fatigue resistant (fr) The largest mn fibres in the spinal cord. Them you get a large fast, twitch contraction that generates. Period will not fire even if receiving more input. *the size recruitment principle*: motor neurons are recruited in order of their size. As force increases, the firing of the motor unit increases proportionally. As you generate more force you increase the firing rate. You also recruit subsequent motor units to increase firing rate. The combination of the two controls muscle force. Normally you have 1:1 relationship between motor fibre and motor unit.
