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2	Skeletal System Bones are made of several tissues Primarily made of collagen and hydroxyapatite - Ca₁₀(PO₄)₆(OH)₂ About 206 bones in the human body
3	Functions of Skeletal System SUPPORT: Hard framework that supports and anchors the soft organs of the body. PROTECTION: Surrounds organs such as the brain and spinal cord. MOVEMENT: Allows for muscle attachment therefore the bones are used as levers. STORAGE: Minerals and lipids are stored within bone material. BLOOD CELL FORMATION: The bone marrow is responsible for blood cell production.
4	Parts of the Skeletal System Axial skeleton Skull and bones that support it Includes vertebra and ribs 80 bones Appendicular skeleton Limbs 126 bones
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6	Joints Where bone meets bone Ligament – holds bone to bone Types of joints: Immovable - skull Ball-and-socket - shoulder Hinge - knee Pivot – forearm Gliding - vertebrae
7	Joints Cartilage covers ends of movable bones Reduces friction Lubricated by fluid from capillaries
8	Cartilage
9	Bone Structure Periosteum – hard outer covering Cells for growth and repair Compact bone – hard strong layer Bone cells, blood vessels, protein with Ca and P Spongy bone – at ends of long bones Has small open spaces to lighten weight Marrow cavity – hollow in middle of long bones
10	Bone Marrow Red marrow – produces blood cells and clotting factors Found in humerus, femur, sternum, ribs, vertebrae, pelvis Produces RBC 2 million per second Yellow marrow – stores fat Found in many bones
11	Bone Structure
12	Haversian System Structure of compact bone Rings of bone tissue with blood vessels and nerves in the center
13	Haversian System
14	Bone Development Initial skeleton of cartilage in infants Replaced with bone by osteoblasts More than 300 bones at birth – fuse to 206 Always growing and breaking down Osteoblasts – form new bone cells Osteoclasts – break bone cells down Osteocytes – mature bone cells
15	Broken Bones Fracture is a break of the bone Simple or Complex fracture Regrowth of bone: Spongy bone forms in first few days Blood vessels regrow and spongy bone hardens Full healing takes 1-2 months
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19	Age Related Dysfunctions
20	Osteoarthritis
21	Osteoporosis
22	Osteoporosis