PSL300H1 Lecture Notes - Lecture 33: Curare, Myofilament, Sarcomere
Document Summary
Only muscle type that is under conscious, voluntary control. Motor neurons (motor neuron + associated muscle fibers = motor unit) A neuron can innervate one or multiple muscles. Chemical signaling bw motor neuron and skeletal muscle is a neuro-muscular junction (nmj) Nmj = synapse bw motor neuron and muscle fiber --> motor neuron"s axon terminal. Organized in a very regular pattern, overlapping with respect to each other --> striated. Has the fasted or best developed sarcoplasmic reticulum (sr) Single muscle fiber shown below to show components. Made up of myofibrils - arranged in regular manner. Some invaginations - t-tubule system - go deep into the muscle. Function: allow quick spread of action potential for deep spreading inside. Skeletal muscle has the best developed out of the three muscles. Muscle fibers of motor unit all contract together. Smoothness and precision of movement dep on number and timing of motor units activated. Muscle contraction begins with small motor units activated first.
