The sarcomere

Possessed by striated (skeletal and cardiac) myocytes.

• Organized parrellel thick and thin filaments.
• Thick filaments primarily = myosin, thin = actin
• Thin filaments bound together at Z-disks
• Zone containing only thin filaments is the I band (I is a very thin letter!) The rest (the thick filaments and the overlap zone) is the A band.
• Compare to smooth muscle, where thick and thin filaments are orgnaized in a hatched mesh and join to the membrane and to dense bodies.