The Skeletal System

Human Skeletal System Overview

  • Adult skeleton: 206 bones; baby skeleton: 300 bones (fuse during growth).

Functions of the Skeleton

  • Supports the body

  • Provides shape

  • Enables movement

  • Protects internal organs

  • Produces blood cells

  • Stores minerals (calcium, phosphorus)

Protection of Vital Organs

  • Organs and their protections:

    • Brain - Skull

    • Lungs - Ribs

    • Heart - Sternum

    • Reproductive organs - Pelvis

Types of Bones

  • Long bones: Weight support & movement (e.g., femur).

  • Short bones: Stability & allow some movement (e.g., carpals, tarsals).

  • Flat bones: Protect internal organs (e.g., pelvis, skull, sternum).

  • Irregular bones: Vary in shape/size (e.g., vertebrae protect spinal cord).

Joints

  • Where two bones meet, allowing movement:

    • Fixed/Immovable (fibrous): No movement (e.g., skull).

    • Hinge joints: Movement like a door (e.g., elbow, knee).

    • Gliding joints: Bones slide over one another (e.g., wrist, ankle).

    • Ball-and-Socket: Full motion (e.g., shoulders, hips).

    • Pivot joints: Rotation (e.g., neck, vertebrae).

Synovial Joints

  • Most common type, allows greatest range of motion.

  • Components:

    • Synovial membrane: Smooth lining inside the joint.

    • Synovial fluid: Lubricant to reduce friction.

    • Cartilage: Shock absorber at bone ends.

Skeletal Tissues

Schedule tissue on normally found where two bones meet. They help reduce friction provide movement and connect other body tissues, and organs

  • Ligaments: Connect bone to bone.

  • Tendons: Connect muscle to bone.

  • Bone Marrow: Produces blood cells.

Skeletal Injuries

  • Range from minor dislocations to compound fractures where multiple bones are broken.

  • Causes: Intense force/pressure is applied to bones.

  • Prevention: Good posture, calcium, and phosphorus-rich foods. They helped to keep the bone strong and healthy.

Common Skeletal Injuries

  • Fracture: Break in bone (varies in severity).

  • Dislocation: Bones at a joint are misaligned.

  • Sprain: Stretched or torn ligament.