Intro to Skeletal System

MAIN FUNCTION OF THE SKELETAL SYSTEM Structural SupportFramework for soft tissue ProtectionSkull  Brain Rib Cage  Lungs & Heart Vertebral Column  Spinal Cord Blood Cell FormationRed blood cells and platelets are made in bones Reservoir of MineralsRegulate level of calcium and phosphorous in the body MovementMuscle attach to bone by tendons – contract and move bones to facilitate movement

Axial vs Appendicular Skeleton The axial skeleton consists of 80 bones: 26 vertebral column, 1 hyoid, 22 skull, 6 auditory & 24 ribs Most muscles anchor & originate here The appendicular skeleton consists of 126 bones: 64 upper extremity – attached to pectoral girdle 62 lower extremity – attached to pelvic girdle Key role in movement Axial (80) + Appendicular (126) = 206 bones

Types of Bones 1.Long 2.Short 3.Flat 4.Irregular 5.Sesamoid Bones classified according to their shape

Anatomy of a Long Bone Cartilage Compact bone Periosteum Cancellous bone Medullary cavity Epiphysis Diaphysis Epiphysis

Definitions to Know Articulating Cartilage – Located at both ends of long bone – Function: protection & smooth movement within joints Perisoteum – Outer connective tissue covers entire length of bone – Function: attachment site for tendons & ligaments

Diaphysis – Shaft of bone Epiphysis – End of bone Compact Bone – Dense part of bone (hard) – Structural integrity – Diaphysis Cancellous (Spongy) Bone – Filled with marrow – Can strengthen with exercise – Epiphysis

Medullary Cavity – Inside shaft of bone – Filled with: Red bone marrow – Blood-cell formation Yellow bone marrow – Fat cells & connective tissue