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The Skeletal System. Major Functions of the Skeletal System. Shape and support for the body Protects inner organs Skull – brain Ribs – heart and lungs Muscles attach to bones Creates red blood cells, white blood cells, and platelets in the marrow Stores calcium and phosphorus.
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Major Functions of the Skeletal System • Shape and support for the body • Protects inner organs • Skull – brain • Ribs – heart and lungs • Muscles attach to bones • Creates red blood cells, white blood cells, and platelets in the marrow • Stores calcium and phosphorus
Bone Structure • Not completely smooth • Bumps, rough edges, pits, holes • Covered by periosteum • Tough, tight fitting membrane • Contains blood vessels, allows oxygen to reach inner bone, allows for wastes to leave
Bone Marrow • Fatty tissue found within bones • Produces red blood cells • 2,000,000/sec • Produces white blood cells • Not as fast as red • Produces platelets
Cartilage • Thick, smooth layer of tissue • Covers ends of bones • Does not contain blood vessels or minerals • Absorbs shock, reduces friction • Painful when it wears away • Bones rub together • Arthritis develops
Bone Development • Osteoblasts • Bone forming cells • Deposit calcium and phosphorus (hardness) • Osteoclasts • Cells that break down bone (normal) • Bones are always being broken down and reformed
Joints • Where two or more bones meet • Held together by ligaments • Tough bands of tissue • Many joints held together by more than one ligament • Ex. knee
Types of Joints • Immovable joints • Allow little or no movement • Movable joints • Allow wide range of movements
Immovable Joints • Includes joints in skull and pelvis
Movable Joints • Pivot • One bone rotates in the ring of another • Ex. Turning your head http://www.dkimages.com/discover/previews/940/672504.JPG
Ball and socket • One bone has a cup like cavity • Another bone has a rounded end that fits inside • Ex. Hips, shoulders http://archive.ncsa.uiuc.edu/Cyberia/VideoTestbed/Projects/NewAnatomy/images/bshoulder.JPG
Hinge • Back and forth movement (like hinges on a door) • Less flexible, more stable • Ex. Elbows, knees, fingers http://www.dkimages.com/discover/previews/940/672450.JPG
Gliding • One bone slides over another • Back and forth motion • Most frequently used • Ex. Wrists, ankles, vertebrae http://www.teachpe.com/images/anatomy/gliding_joint.jpg
Bone Shapes • Short –toes (phalanges) • Small precise movements • Support weight • Long – legs & arms, length of fingers • Strong • Support weight • Allow movement
Bone Shapes • Flat – ribs, sternum & shoulder • Protect organs • Irregular – vertebrae & inner ear • Support - vertebrae • Hearing – inner ear