KINESIOL 2C03 Study Guide - Midterm Guide: Perimysium, Muscle Spindle, Reuptake
15 Sep 2016
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Document Summary
Skeletal muscle makes up 40-45% and 23-25% of adult male / female body weight respectively. Fibres bound into bundles called fasiculi (singular = fasciculus = fascicle) Muscle fibres have multiple nuclei per cell which lie just beneath the sarcolemma. Endomysium: meshy ct network around each fibre in a fascicle. Epimysium: ct covering of a group of fascicles. 1000s of fibres per muscle, each 10-100 m thick (1000 m = 1 mm) Few mm several cm long; ~ 1 m space between fibres don"t want a lot of extracellular space. Myofibrils makeup 80-85% of the volume of a muscle fibre; made up of sarcomeres in series. The rest of glycogen, sarcoplasmic reticulum (used for nerve impulses, contraction, etc) 1-2 m in diameter; few hundred several thousand per fibre. Made up of thick and thin filaments myosin and actin. M-line: middle of filaments, no cross bridges. A band: overlap of actin and myosin; dark filament overlap = dark part of striation.
