3. Overview  There are 206 bones in the body  The Skeletal System Supports and protects the body Produces red blood cells Storehouse for inorganic calcium, phosphate ions, and fat Permits flexible movement

4. Parts  Bones Skeleton  Cartilages Flexible connective tissue  Joints Where two or more bones make contact  Ligaments Connects two bones or cartilages or holds a joint together

5. Bones throughout our lives  During the embryos stages, the skeleton is mostly cartilage  As we develop, the cartilage gets replaced by bone

6. Types of Bone Tissue  Compact: Found on the outside of most bones. Gives the smooth/ white appearance. Functions include support and protection

7. Types of Bone Tissue  Spongy: Located inside the bone. Make up large portion of bone. Contains many open spaces.

8. Types of Bone Cells  Osteocytes: Mature bone cells  Osteoblasts: Bone-forming cells  Osteoclasts: Bone destroying cells. Break down bone matrix for remodeling and release of calcium

9. Bone Classification  Short: As wide as they are long. Provide support and stability with little movement. ○ (Carpals)

10. Bone Classification  Long: Length is greater than width. ○ (Femur, Phalanges, etc.)

11. Bone Classification  Irregular: Odd shaped that don’t fit any other categories ○ (Pelvis, Vertebrae) Female PelvisMale Pelvis

12. Bone Classification  Flat: Strong, flat, curved plates that provide protection. ○ (Scapula, Sternum, Skull)

13. Divisions  The Skeletal System is divided into two different sections: Axial Skeleton: ○ Skull, hyoid bone, vertebral column, and thoracic cage Appendicular Skeleton: ○ Limbs and girdle

14. Axial Skeleton  Contains 80 bones  Skull (22 bones) Composed of cranium and facial bones  Hyroid bone U-shaped bone in neck Anchors tongue  Vertebral column (26 bones) Protects the spinal cord  Thoracic cage (27 bones) Protects organs

15. Axial Skeleton Diagram

16. Appendicular Skeleton  Contains 126 bones  Pectoral Girdles (4 bones)  Hands (54 bones)  Arm and Forearm (6 bones)  Pelvis (2 bones)  Feet and Ankles (52 bones)  Thigh and Leg (8 bones)

17. Appendicular Skeleton Diagram

18. Joints  Where two bones come together  Fibrous: No movement, connect bones. ○ (Skull and Pelvis)  Cartilaginous: Slightly moveable, bones are attached with cartilage ○ (Spine and ribs)  Synovial: Completely Moveable. Space between bones is filled with synovial fluid to lubricate and protect the bones

19. Synovial Joints  Based on shape Plane joint Hinge joint Pivot Joint Ball-and-socket joint Condyloid joint Saddle joint

20. Synovial Joints  Plane joint Only allows gliding movement (Hands, feet)

21. Synovial Joints  Hinge joint Allows Extension and retraction of an appendage (Knee, elbows)

22. Synovial Joints  Pivot joint One bone rotates around another Only one pivot joint in body (Where the skull joints with vertebrae)

23. Synovial Joints  Ball-and-Socket joint Allows movement in almost any direction (Hip, Shoulder)

24. Synovial Joints  Condyloid joint Egg shaped surface fits into an elliptical surface (Wrist joint)

25. Synovial Joints  Saddle joint Surfaces contrast each other in convex/concave form. (Thumb)