PHSL-P 416 Lecture Notes - Lecture 22: Muscle Contraction, Motor Neuron, Myocyte
Document Summary
Recruitment: motor neuron activation: always 1st strategy used & always used in muscle contraction, voluntary sensory stimulation, when recruited, ca+ is released: crossbridge cycling occurs. Orderly motor unit recruitment: follows motor neuron size: henneman"s principle, small motor neurons are easier to recruit(cell body size) Muscle fiber type matters: small force--> large force. High frequency: decrease sarcomere to minimum length(=max force) Cross bridge cycle--> more cross bridge cycle recruitment/frequency. *order + frequency: add each motor neuron to summate & generate enough force, working our way up from force to higher force. Work way from slow fibers/low ratio--> fast fibers/high ratio: action potentials from 1st neuron, only voluntary contraction. Initial sarcomere length affects how much force it can produce. Moderate overlap of actin & myosin will lead to highest force output: shortest length it can get: no more additional force, too long to generate force, moderate overlap, can shorten, max binding/max force.
