1. Anatomy and Physiology
The Skeletal System
Anatomy and Physiology

2. Bone A connective tissue
Contains bone tissue, cartilage, fibrous connective tissue, blood, and nervous tissue
It is alive!

3. Functions Provides points of attachment for muscles Protection Support
House blood producing cells
Store inorganic salts and minerals

4. A typical bone Epiphysis: large knob on the ends Diaphysis: long shaft
Periosteum: covering over all
Compact bone: hard and rigid outside
Spongy bone: spongy and contains marrow
Articular cartilage: smooth surface on bone ends

5. Spongy bone and marrow Spongy bone is near the ends in the epiphyses
Contains red marrow, which produces blood cells (fills an infant’s)
Yellow marrow is in the medullary cavity, and stores fat, more in an older adult

6. Compact Bone osteocyte Tightly packed Cells are called osteocytes
Surrounded by fibers and cemented by hard background
The structure forms around an osteonic canal, with blood vessels and nerves in the center
Osteonic canal

7. Osteonic Canals: bone grows in concentric circles
Only in the compact bone!

8. Bone Cells Osteoblasts: are bone forming cells
When they mature and become surrounded with the hard matrix, they are osteocytes
Osteoclasts: break down bone

9. Osteoblasts and Osteoclasts
When would osteoblasts be working?
When forming new bone for growth, repair, replacement of aging or dying bone
When would osteoclasts be working?
When dissolving older bone containing dead cells, or to release calcium into the bloodstream if needed

10. Calcium Levels
If too low, parathyroid gland senses this and secretes parathyroid hormone (PTH)
PTH stimulates osteoclasts to break down bone and release calcium into blood
Calcium levels in the blood return to normal

11. Calcium Levels
If too high, thryoid gland senses this and secretes calcitonin
Calcitonin stimulates osteoblasts to form new bone, depositing calcium in the new bone
Calcium levels in blood return to normal

12. Why do we need calcium in the blood?
For muscle contraction
Nerve impulse conduction
Blood clotting
Other processes

13. Orange: is axial
Yellow: is appendicular

14. Types of Skeletal Joints
Fibrous: immovable, ex: sutures of skull
Cartilaginous: bones connected by cartilage; limited movement; ex: vertebrae
Synovial: bones surrounded by capsule and synovial membranes; ends of bones are covered in cartilage and surrounded by synovial fluid; lots of movement

15. Fibrous
Connected by thin layer of fibrous connective tissue

16. Cartilaginous Connected by cartilage
Limited movement, as when back is twisted or bent

17. Synovial

18. Synovial Ball and Socket Hip and shoulder
Ball shaped head joints with the cup of the other bone
Circumduction

19. Synovial
Condyloid: oval shape of one bone joints with elliptical cavity of the other

20. Synovial
Gliding: surfaces are nearly flat
Wrist, ankle

21. Synovial Hinge: convex surface joins with a concave surface
Flexion and extension
Elbow and knee

22. Synovial Pivot: can rotate around a central axis
Proximal ends of radius and ulna

23. Synovial Saddle: surface of bones are both convex and concave; fits in
Only occurs in the joint between the carpal and the metacarpal of the thumb