The Skeletal System

1. The Skeletal System Pablo de Esteban Camila Rodriguez

2. The Skeleton • Supports the body • Protects internal organs • Provides for movement • Stores mineral reserves • Allows an area for blood cell formation

3. Bones A solid network of living cells and protein fiber that are surrounded by deposits of calcium cells. • Infants: 350 bones • Adult: 206 bones

4. Structure of Bones • Periosteum: tough layer of connective tissue that surrounds the bone through which Blood vessels pass caring oxygen and nutrients to the bones. • Haversian canal: runs through compact bone, beneath peritoneum, contains blood vessels and nerves. • Spongy bone: adds strength to the bone. Bone marrows: cavity that contains soft tissue • Yellow marrow: made up of fat cells • Red marrow: produces red blood cells, some white cells, cell fragments (platelets)

6. Development of bones Cartilage: connective tissue scattered into a network of protein fibers. • Strong and flexible

7. Development of Bones • Ossification:process in which cartilage is replaced by bone. Cells involved: 1. Osteoblasts: secrete mineral diposits that produces new bone tissue to replace the cartilage into bone. 2. Osteocytes: the mature form of Osteoblasts surrounded by bone tissue, mantains cellular activities of the bone. 3 .Osteoclasts: breaks down bone removing damaged bone tissue.

8. Ossification

9. Joints Are the place where one bone attaches to another.

10. Types of joints • Immovable joints • Slightly movable joint • Freely movable joint

11. Immovable Joints • Allows no movement because the bones are interlocked and held together by connective tissue ex: where the bones in the skull meet

12. Slightly Movable Joints • Permit a small amount of restricted movement. The bones in these areas are separated from each other.

13. Freely Movable Joints • Permit movement in one or more direction • Grouped according to the shapes of the surfaces of the adjacent bones http://www.jeffsims.net/flash/skeleton.html

14. Structure of Joints • Joint Capsule: surrounds the joints and helps hold the bones together while still allowing them to move. • Layers: • Ligaments: surrounds bones and holds them together. • Cells in the other layer produce a substance called synovial fluid => lubricating film which enables the ends of the bones to slip past each other smoothly.