A pivot joint allows for rotational movement around a single axis.

Bone matrix is composed mainly of calcium phosphate (hydroxyapatite) which provides rigidity.

Tendons connect muscle to bone, while ligaments connect bone to bone.

The masseter is the principal muscle of mastication.

The cervical region of the human vertebral column consists of 7 vertebrae.

The elbow joint is a classic example of a hinge joint, allowing motion primarily in one plane.

The sarcomere is the basic contractile unit of a muscle fiber.

Myosin is the thick filament, while actin is the thin filament involved in muscle contraction.

Synovial fluid lubricates joints to reduce friction and allow smooth movement.

Red bone marrow contains hematopoietic stem cells which are responsible for the formation of red blood cells (erythropoiesis).

Bones act as a reservoir for calcium, releasing it into the bloodstream when levels drop to support nerve and muscle function.

Smooth muscle, also known as involuntary muscle, is found in the walls of hollow organs and structures like the intestines, bladder, and arteries.

Ball-and-socket joints allow movement in multiple axes, including rotation, flexion, extension, abduction, and adduction.

Ligaments are fibrous connective tissues that hold bones together at joints, providing stability.

The H-zone, which contains only thick filaments, narrows and disappears during full contraction as actin filaments slide into the center.

Osteons are the cylindrical structural units of compact bone, consisting of concentric layers of matrix called lamellae.

Titin is a giant protein that functions as a molecular spring, providing elasticity to muscle fibers and helping them return to resting length.

The clavicle is a long bone that serves as a strut between the shoulder blade and the sternum, commonly known as the collarbone.

During anaerobic respiration in muscle cells, lactic acid is produced, which has traditionally been linked to the sensation of muscle fatigue.