Kinesiology 1080A/B Lecture Notes - Lecture 26: Quadriceps Femoris Muscle, Alpha Motor Neuron, Upper Motor Neuron

• School: Western University
• Department: Kinesiology
• Course: Kinesiology 1080A/B
• Professor: Matthew Heath

Document Summary

Cigar-shaped structure connected in parallel with muscle fibers. Innervated by gamma motor neurons (fusi motor neuron system) Provides information about dynamic (velocity component) and static (constant state of tension) stretch of the muscle. Two types: type 1a, which is responsible for the dynamic stretch, type ii, which is responsible for static stretch. Provides system with info about limb position. Bag fibers contain both type 1a and ii. Free nerve endings rate sensitivity: type 1a really sensitive to rapid stretch of the muscle (i. e. , when the agonist first begins contraction, type ii sensitive to sustained level of contraction of the agonist muscle. In picture, there is 3 different states of the muscle. The muscle is the agonist muscle: the ticks are the nerve signal output; more ticks high firing rate, red line: contraction that is occurring. First graph: tonic firing rate- getting output from both, neither are more active than the other. Muscle spindle sends information in the spinal cord.