Gross Anatomy of Skeletal Muscle Muscle fiber Endomysium Fascicle Perimysium Epimysium Deep facia
Connective Tissue Sheaths Endomysium Perimysium Epimysium Collagen fibers of all 3 layers come together at each end of muscle to form a tendon or aponeurosis.
Microscopic Muscle Fiber Anatomy Sarcolemma - ‘cell membrane’ Sarcoplasm - ‘cytoplasm’ Myoglobin** Transverse tubules Sarcoplasmic Reticulum Myofibrils A band I band
Myofibril Myofilaments Two types Actin (+ 2) filaments (thin filaments) Myosin filaments (thick filaments)
Sarcomere Between 2 Z-discs Contractile Unit Sarcomere + sarcomere + sarcomere = myofibril A band
I bands
Z lines Sarcomere
Actin and Myosin Filaments
Myosin (Thick) Filament 1 protein Generates tension
Actin (Thin) Filament Three proteins Actin (contractile) Troponin (lock) Tropomyosin (door)
axon T tubules myofibrils sarcomere plasma membrane