GENERAL HISTOLOGY

Detailed explanation-1: -The myofibrils are made up of thick and thin myofilaments, which help give the muscle its striped appearance. The thick filaments are composed of myosin, and the thin filaments are predominantly actin, along with two other muscle proteins, tropomyosin and troponin.

Detailed explanation-2: -Myofibrils are composed of long proteins including actin, myosin, and titin, and other proteins that hold them together. These proteins are organized into thick, thin, and elastic myofilaments, which repeat along the length of the myofibril in sections or units of contraction called sarcomeres.

Detailed explanation-3: -A sarcomere is the basic contractile unit of muscle fiber. Each sarcomere is composed of two main protein filaments-actin and myosin-which are the active structures responsible for muscular contraction.

Detailed explanation-4: -The cytoplasm contains many myofibrils-tiny cylinders consisting of bundles of myofilaments. The myofilaments include thick filaments, composed mainly of myosin, and thin filaments composed mainly of actin.