1. Skeletal System

2. The Skeletal System What is the Skeletal System? – A system of mineralized hard and soft tissues that span the inside of the body. –“ Frame work ” of your body

3. The Skeletal System Three things that make up the skeletal system: – Bones: hard mineral tissue (calcium) – Cartilage: tough, flexible connective tissue – Joints: Places where two or more bones meet

4. The Skeletal System Purpose of the Skeletal System: – Protect internal organs and soft tissues. – Support of your body organs against the pull of gravity – Something for muscles to hold onto so you can move – Storage for necessary minerals (calcium) & fats – Produces Blood for the body

5. The Skeletal System Major Divisions in the skeletal system: – Axial: Bones along the center axis (medial) of the body. Skull, Vertebral column, rib cage

6. The Skeletal System Major Divisions in the skeletal system: – Appendicular: consists of appendages that attach to the axial skeleton. Pectoral girdle, pelvic girdle, limbs

7. Axial Appendicular

9. The Skeletal System Bone Formation: – Start out as cartilage – Eventually form bone Baby: 350 bones Adult: 206 Bones – Specialized cells continuously break down and reform bone

10. Compact bone: dense and looks smooth and homogeneous Spongy bone: composed of small needlelike pieces of bone and lots of open spaces The Skeletal System

11. Types of Bones: – Flat: Thin, flattened and usually curved Two thin layers of compact bones sandwiching a layer of spongy bone between them E.g. Skull, ribs and the sternum

12. The Skeletal System Types of Bones: – Long: Longer than they are wide Contain mostly compact bone Like steel beams, these weight bearing bones provide structural support All the bones of the limbs, except the wrist and ankle bones, are long bones

13. The Skeletal System Types of Bones: – Short: Approx. as wide as they are long Contain mostly sponge bone Look like blocks and allow wider range of movement than larger bones E.g Carpals of the wrist

14. The Skeletal System Types of Bones: – Irregular: Bones with complex shapes that are not easily fit into other categories Usually have projections that muscles, tendons, and ligaments attach to E.g. Vertebral column, facial bones