In muscle physiology, thick filaments and thin filaments are the two main types of protein filaments that are responsible for muscle contraction. Here are the differences between them:
Composition: Thick filaments are composed of myosin, while thin filaments are made up of actin, tropomyosin, and troponin.
Size: Thick filaments are larger in diameter than thin filaments.
Arrangement: Thick filaments are arranged in a hexagonal lattice around the thin filaments, while thin filaments are arranged in a double helix.
Function: During muscle contraction, the thick and thin filaments interact with each other to create a sliding motion that shortens the muscle fiber. Myosin heads on the thick filaments bind to actin on the thin filaments and pull them toward the center of the sarcomere, which results in muscle contraction.
Localization: Thick filaments are localized in the A band of the sarcomere, while thin filaments are found in both the I band and A band of the sarcomere.
