KINESIOL 2C03 Study Guide - Midterm Guide: Myosin Head, Troponin T, Endoplasmic Reticulum
2 Apr 2016
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Muscle fasciculus muscle fibre myofibril sarcomeres myofilaments (actin and myosin) Muscle: skeletal muscle makes up 40-45% of adult male and 23-25% of adult female body weight. 1000s of fibres per muscle (biceps = 200,000) Fibres are 10-100 um thick (largest as thick as human hair) Length: a few mm to several cm long (about 1 um space between fibers) Polygonal in shape to allow greater packing density (instead of cylindrical) Make up ~80-85% of contents of fibre. A few hundred to a few thousand myofibrils per fibre. Actin: thin filaments, pearl strand, 6nm wide, 1 um long: troponin every 7 globular actin, tropomyosin. Myosin: thick filaments, cross bridge heads, 16 nm wide, 1. 5 um long. Sarcomeres can vary in length depending on degree of filament overlap. Sarcomeres can vary in number depending on muscle length. Working range: 3. 5-1. 5 um = 2 um. See working range of myofibril/muscle fibre in notes. ~12 cm = 120 mm = 120,000 um.
