Skeletal System Overview

• The skeletal system provides structural support for the body, protecting internal organs and providing attachment points for muscles.

• It comprises bones, cartilage, ligaments, and tendons, working together to facilitate movement and maintain posture.

Bone Structure and Types

• Bones are composed of a hard, outer layer of compact bone and a spongy inner layer filled with bone marrow.
• Compact bone is dense and strong, providing structural support.
• Spongy bone is porous and lightweight, reducing the overall weight of the skeleton.
• Bones are classified into long, short, flat, and irregular bones based on their shape and function.

Bone Composition and Functions

• Bones are primarily made of calcium phosphate, a vital mineral that contributes significantly to their strength and density.
• Other components like collagen provide flexibility and resilience.
• Bones are responsible for supporting and protecting vital organs such as the brain, lungs, and heart.
• They act as levers for movement, facilitated by skeletal muscles.

Bone Marrow

• Bone marrow is a soft tissue found within the cavities of bones.
• Two types of bone marrow exist: red bone marrow and yellow bone marrow.
• Red bone marrow produces blood cells (red blood cells, white blood cells, and platelets).
• Yellow bone marrow primarily stores fat.

Joints

• Joints are the points of articulation between two or more bones.
• Different types of joints exist, including fibrous joints (immovable), cartilaginous joints (slightly movable), and synovial joints (freely movable).
• Synovial joints are the most common and complex type.
• They contain synovial fluid, which lubricates the joint and reduces friction during movement.

Types of Movement at Joints

• Joints allow flexion (bending), extension (straightening), abduction (moving away from the midline), adduction (moving towards the midline), rotation, and circumduction (circular movement).
• The specific range of motion at a joint depends on the type of joint and surrounding tissues.

Skeletal Muscles and Movement

• Muscles work in pairs to produce movement.
• When one muscle contracts, the opposing muscle relaxes.
• Different types of muscles are responsible for various movements (e.g., voluntary or involuntary).

Bone Growth and Repair

• Bone growth occurs primarily during adolescence and is influenced by hormones like growth hormone and sex hormones.
• Bones continuously remodel throughout life, allowing for repair and adaptation.
• The process of fracture repair is complex, involving a series of stages.

Factors Influencing Bone Health

• Adequate intake of calcium and vitamin D is crucial for healthy bone development and maintenance.
• Sufficient physical activity and weight-bearing exercises stimulate bone growth and density.
• Certain lifestyle choices, such as smoking and excessive alcohol consumption, can negatively impact bone health.

Common Skeletal Disorders

• Osteoporosis is a condition characterized by decreased bone density, increasing the risk of fractures.
• Arthritis is a general term for conditions affecting the joints, often causing pain and inflammation.
• Scoliosis is a sideways curvature of the spine.
• These disorders can have significant impacts on mobility and overall health.