Skeletal System of Man

Chapter Overview

The skeletal system provides structural framework, protection, and facilitates locomotion in humans. Bone tissue consists of specialized cells (osteoblasts, osteoclasts, and osteocytes) embedded in a calcified matrix, while cartilage provides flexible support. The human skeleton is divided into the axial skeleton (skull, vertebral column, rib cage) and the appendicular skeleton (pectoral girdle, upper limbs, pelvic girdle, lower limbs). Joints connect these bones, classified as fibrous (immovable), cartilaginous (slightly movable), and synovial (freely movable).

Common skeletal disorders include slipped disc, spondylosis, sciatica, osteoporosis, and various forms of arthritis. In the event of injury, bones can fracture, undergoing a structured repair process involving hematoma formation, fibrocartilaginous callus formation, bony callus formation, and bone remodeling. Injuries to joints, such as dislocations and sprains, require proper first aid. Muscle tissue is categorized into smooth, cardiac, and skeletal, with skeletal muscles being attached to bones to execute movement.

The ultra-structure of skeletal muscle consists of myofibrils containing actin and myosin filaments. According to the sliding filament model, muscle contraction occurs when actin filaments slide past myosin filaments, driven by ATP hydrolysis and regulated by calcium ions. Muscle coordination relies on the antagonistic arrangement of skeletal muscles, such as biceps and triceps. Understanding these biomechanical concepts is crucial for HSSC-II SLO-based examinations.