EQN 3050 Lecture Notes - Lecture 1: Glycogen Phosphorylase, Myocyte, Myosin Head
20 Jan 2017
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Document Summary
Muscle mass comprises ~55% of the horses body weight. 3 types of muscles: smooth (involuntary, cardiac (heart, skeletal (striated/voluntary) Muscle contraction: nerves and muscles working together, motor unit. Gut, blood+ lymphatic vessels, respiratory tract, repro tract, bladder, eyes. Consists of a neuron and all the fibres innervated by that neuron. # of fibres innervated by neuron is proportional to magnitude of force produced by muscle. Supply motor units with few muscle fibers. Low force, fine motor control (eg: eyes: wide diameter. Supply motor units with many muscle fibres. High force, gross motor control (eg: hindquarter muscles) Depolarization: opening of achr channels letting na+ to rapidly enter the cell, opening of voltage-dependent na+ channels, t-system depolarization results in ca2+ release from sr and initiates contraction. Repolarization: opening of k+ channels letting k+ rush out, closing of na+ channels, membrane potential restored via na/k-atpase. Moving ions into and out of the cell.
