The Skeletal System

Structure and Functions

• The skeletal system is primarily made of bones and joints, along with supporting tissues like ligaments and cartilage.
• It serves as the body's framework, providing shape and support.
• The main function is to protect vital organs such as the heart and brain.
• It assists in movement, as skeletal muscles are attached to bones.
• The skeletal system is vital for blood cell production, which occurs in the bone marrow.
• Bones also act as a storage site for minerals like calcium and phosphate.

Types of Bones and Their Roles

• Long bones (e.g., femur, humerus) provide strength and mobility.
• Short bones (e.g., carpals of the hand, tarsals of the foot) are often cube-shaped and provide support and stability.
• Flat bones (e.g., skull, rib cage) serve a protective role.
• Irregular bones (e.g., vertebrae, facial bones) are uniquely shaped to serve specific functions.
• Sesamoid bones (like the knee) are embedded in tendons or muscles and reduce friction and wear.

Bone Composition

• Bones are living tissues made up of calcium and phosphate, giving hardness and strength.
• The layer of compact bone on the outside is dense and ensures rigidity.
• Inside, a network of spongy bone is present. It is lightweight but strong.
• The periosteum is a membrane that surrounds the bone, delivering nutrients and removing waste products.

Joint Types and Movements

• Pivot joints (e.g., neck) allow rotational movement.
• Hinge joints (e.g., elbows, knees) enable movement in one direction, similar to the opening and closing of a door.
• Ball and socket joints (e.g., shoulder, hip) allow a wide range of motion in several directions.
• Saddle joints (e.g., thumb) allow movement in two directions.

Health and Disease

• Regular exercise helps enhance bone density and reduces the risk of osteoporosis.
• Fractures are common injuries in the skeletal system due to impact or excessive force.
• Arthritis is a degenerative condition affecting joints, causing swelling and pain.
• Osteoporosis is a disorder where bones become brittle and fragile due to loss of tissue.
• Adequate intake of calcium and Vitamin D is important for strong bones. Exercise and a balanced diet are also crucial.