Anatomy of Myofilaments
Thin Filament
Filament of actin units, tropomyosin and troponin
Actin
Each subunit has a myosin binding site
Tropomyosin
Long filament that covers myosin binding sites on actin when muscle is at rest
Sarcomere (Z line to Z line)
Contractile unit of muscle fiber
Thick Filament
Consists of many myosin molecules
Myosin Molecule
Shaped like a golf club; in high energy configuration, it attaches to actin
Troponin
Has binding sites for:
1. tropomyosin
2. actin
3.
calcium (if present)