SkeletalMusclestructureShape: Long, cylindrical cellsNu:flattened,MultinucleatedbeneathsarcolemmaSarcoplasm: myofibrils;crossstriationsalternatingdark and light bands
structure Shape: Long, cylindrical cells Nu: flattened, Multinucleated, beneath sarcolemma Sarcoplasm: myofibrils; cross striations alternating dark and light bands Skeletal Muscle
1)myofibrilsAbandZ lineIbandLMlightband=Ibanddarkband=AbandA band, I band, Z line,H band, M lineSarcomereSarcomere:1/2 /+ A + 1/2 Ishortestcontractileunitofskeletalmuscle.MusclefibreMyofibrils
A band, I band, Z line, H band, M line Sarcomere: 1/2 I + A + 1/2 I shortest contractile unit of skeletal muscle. A band Z line I band • light band= I band •dark band =A band LM 1) myofibrils Sarcomere
EMlongparallel,cylindricalfilamentousbundles(thin & thick)consisting of two types of myofilamentAHZ line1MlineHSarcomere
EM long , parallel , cylindrical filamentous bundles consisting of two types of myofilament (thin & thick) H Z line A I M line Z Z H Sarcomere
a.Thickfilamentsoccupying A band, fixation M linemyosinmoleculesrods overlap; globular heads direct toward eitheroftheendsformingcrossbridgesandhaveATPaseactivitySarcomereAbandHbandZdiskTitinNebulinm band
a. Thick filaments occupying A band, fixation M line myosin molecules rods overlap; globular heads direct toward either of the ends forming cross bridges and have ATPase activity