NEET BIOLOGY

Detailed explanation-1: -Muscle cells are excitable; they respond to a stimulus. They are contractile, meaning they can shorten and generate a pulling force. When attached between two movable objects, in other words, bones, contractions of the muscles cause the bones to move.

Detailed explanation-2: -During a concentric contraction, a muscle is stimulated to contract according to the sliding filament theory. This occurs throughout the length of the muscle, generating a force at the origin and insertion, causing the muscle to shorten and changing the angle of the joint.

Detailed explanation-3: -Each strand is made up of sub-units called “sarcomeres.” These sarcomeres contain the “contraction proteins” called actin and myosin. The chemical interactions of these two proteins are responsible for the abilities of the muscle to contract (shorten), relax and produce force (necessary to move the body or objects).

Detailed explanation-4: -Muscle tissue is composed of cells that have the special ability to shorten or contract in order to produce movement of the body parts.

Detailed explanation-5: -Muscle contraction entails the sliding of the thin filaments past the thick filaments, resulting in shortening of the sarcomere and, thus, the entire myocyte.