PHIL 2130 Chapter Notes - Chapter 1.6: Motor Unit, Myocyte, Anti-Gravity
6 May 2020
School
Department
Course
Professor
Document Summary
Motor unit = single motor neuron and all the muscle fibres it innervates, number of fibres vary. All or non principle, motor unit contracts as a whole. Force developed proportional to number of motor unit recruited, precise contraction. Fibres of motor units intermingle, smooth contraction. Active motor units generate tension, avoid fatigue by rotating unit activation. Mainly antigravity muscles involved in balance and posture. Aerobic metabolism: o2, organic molecules and mitochondrial enzymes. Slow twitch: use all day, require a lot of atp, therefore uses aerobic metabolism for atp. Fast twitch, burst of energy, stronger contraction and tension, uses anaerobic metabolism. Increase mitochondria, glycogen reserves, glycolytic enzymes, myofibrils. Larger muscles, larger cells, generate more tension. Initially reversible, but can be permanent disability if left untreated. Generate ap by pace maker cells, unstable membrane potential. Cardiocytes form branching network joined at intercalated discs. Fasica adherens, anchorage of actin filaments of terminal sarcomeres. Desmosomes, anchorage of intermediate filaments of cytoskeleton.
