1. Support Protection Movement
The Skeletal System
Support
Protection
Movement

2. Topics covered Structure and development Remodel and repair
How bones fit together to make the skeleton
How joints enable bones and muscles to work together
Problems with the skeletal system

3. Skeletal system consists of 3 types of connective tissue
Bones – the hard elements
Ligaments – dense, fibrous connective tissue that binds bone to bone
Cartilage – special connective tissue of fibrous & elastic collagen in a gel-like fluid called “ground substance”

4. Long bone

5. ligaments

6. Cartilage

7. Bones: The hard elements
Most bone mass consists of nonliving extra cellular crystals of calcium minerals
Also consists of:
Living bone cells, nerves and blood vessels (bones bleed when they are cut or broken!)

8. 5 Bone Functions Support Movement Protection Formation of blood cells
Mineral storage

9. 1. Support
Bones form the structure (skeleton) to which the skeletal muscles are attached

10. 2. Movement
Bones support and interact with muscles making movement possible

11. 3. Protection
As hard elements bones surround and protect many delicate internal organs

12. 4. Blood cell formation
Certain bones contain cells that are responsible for making different types of blood cells

13. 5. Mineral Storage
Calcium, phosphates which are important to metabolic function

14. Long bones Longer than wide Cylindrical shaft called diaphysis
Enlarged knobs at each end called epiphysis
Compact bone forms the shaft and covers each end
Central cavity of the shaft is filled with yellow bone marrow (primarily fat for energy)

15. Epiphysis
Inside each epihysis is spongy bone that is less dense than compact bone making it light, but strong
Spongy bone is a lattice work of hard relatively strong trabeculae (L. little beams) made of calcium, minerals and living cells

16. Long bone special function
Upper arms and legs (humerous and femur) contain spaces between the trabeculae that are filled with red bone marrow.
Stem cells in the red marrow are responsible for the production of red and white blood cells and platelets

17. Outer surface - periosteum
Bones are covered by tissue called periosteum that contains specialized bone forming cells: osteocytes (Gk. Bone & cells)
Osteocytes are arranged in rings in cylindrical structures called osteons (sometimes called Haversian systems)

19. Periosteum cont’d
As bone develops and hardens osteocytes become trapped in chambers called lacunae – but stay in touch with each other via canals called canaliculi.
Canaliculi are used to pass nutrients between adjacent osteocytes to nurture bone cells when far from blood vessels

20. Osteocytes in lacunae
Waste products diffuse in the opposite direction and are removed by the blood vessels for transport to urinary system

21. Osteocytes in trabeculae
In spongy bone osteocytes don’t need canals for nutrients and waste transportation – the trabeculae structure gives the osteocytes access to nearby blood vessels in the red marrow