Functions and Anatomy of the Skeletal System

Functions of the Skeletal System

• Support the body
• Store minerals and lipids
• Produce blood cells
• Protect internal organs
• Provide leverage for movement

General Classifications of Bones

• Long Bones (e.g., humerus)
• Short Bones (e.g., carpal bones)
• Flat Bones (e.g., parietal bone)
• Irregular Bones (e.g., vertebrae)

Anatomy of Bones

• Periosteum: Outer covering of the bone
• Epiphysis: End of a long bone
• Diaphysis: Shaft of a long bone
• Medullary Cavity: Hollow space within the diaphysis
• Bone Marrow: Contains yellow and red marrow
• Yellow Marrow: Stores fat, mostly in adults
• Red Marrow: Produces red and white blood cells

Bone Tissue

• Compact Bone: Dense, hard material found in shafts of long bones, outer layer of other bones.
• Spongy Bone: Arranged in bars and plates, making bones lighter in weight.

Bone Growth and Repair

• Ossification: Bone formation
• Osteoprogenitor Cells: Stem cells that give rise to osteoblasts
• Osteoblasts: Bone-forming cells
• Osteocytes: Mature bone cells that maintain the bone matrix
• Osteoclasts: Bone-resorbing cells

Bone Growth and Repair - Types of Ossification

• Intramembranous Ossification: Occurs within flat bones
• Endochondral Ossification: Occurs within cartilage template bones.
• Stages of bone repair: the process of healing a broken bone is a complex sequence from forming a hematoma to the formation of a bony callus etc. and finally the remodeling process

Appositional Bone Growth

• Bones continuously increase in diameter (width)
• Bone is added on the outer surface whilst it is removed in the inner surface.

Bone Repair

• Hematoma Formation: Blood clot forms at the fracture site.
• Inflammation: Tissues around the fracture swell and become inflamed.
• Fibrocartilaginous Callus: Cartilage and bone tissue forms at the fracture site.
• Bony Callus: Bone tissue replaces part of the cartilage in the callus.
• Remodeling: Bone tissue is rearranged to strengthen it and/or give it a normal shape.

Cartilage

• A form of connective tissue
• Provides flexibility, cushioning, and shock absorption
• Found in joints

Joints and Ligaments

• Synovial Joints: Provide a range of movement. Examples include:
  • Gliding Joints
  • Hinge Joints
  • Saddle Joints
  • Ellipsoidal (condyloid) Joints
  • Pivot Joints
  • Ball-and-Socket Joints

Movement

• Various types of movements occur at joints

Special Regions of the Skeleton

• Axial Skeleton: Forms the central part of the body. Includes the skull, vertebral column, and bony thorax
• Appendicular Skeleton: Includes the limbs and the girdles

Human Skull

• Composed of various bones
• Important for protection of the brain
• Sutures join the bones of the skull

Bony Thorax

• Consists of the sternum and ribs
• Protects the heart and lungs

Spinal Column

• Vertebral column: Protects the spinal cord
• Consists of cervical, thoracic, lumbar, sacrum, and coccyx.

Upper and Lower Extremities

• Includes bones of the arms, legs, hands, and feet.

Fun Facts about Bones

• 1/5 of the skeleton is replaced annually (remodeled, not entirely new)
• Regular exercise maintains bone strength
• Calcium is a major component of bones (99% )
• Bone density typically begins to decrease after age 30.

Explore the essential functions of the skeletal system, including support, mineral storage, and protection of organs. This quiz also covers the different classifications of bones, their anatomy, and processes related to bone growth and repair.