Intro to Skeletal System
Jan 29, 2016
Intro to Skeletal System
MAIN FUNCTION OF THE SKELETAL SYSTEMStructural Support Framework for soft tissue
Protection Skull BrainRib Cage Lungs & HeartVertebral Column Spinal Cord
Blood Cell Formation Red blood cells and platelets are made in bones
Reservoir of Minerals Regulate level of calcium and phosphorous in the body
Movement Muscle 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. Long2. Short3. Flat4. Irregular5. Sesamoid
Bones classified according to their shape
Anatomy of a Long BoneAnatomy of a Long BoneCartilage
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