The Skeletal System

1. The Skeletal System

2. Outline - Introduction • Tissues of the Skeletal System • Bone Growth and Repair • Bone Development • Bone Repair • Bones of the Skeleton • Bone Classification • Axial and Appendicular Skeleton • Articulation • Movements Permitted by Joints

3. Tissues of the Skeletal System I) Introduction II) Connective Tissues A) Bone B) Cartilage C) Fibrous connective tissue

4. A) Bone (Ca2PO4 + mineral salts) • 1) Compact bone - organized, tubular osteons. • Osteocytes lie in lacunae, tiny chambers arranged in concentric circles around a central canal. Canaliculus • 2) Spongy bone – trabeculae, unorganized. • Spaces are often filled with red bone marrow. Osteocytes irregular

8. B) Cartilage • Cartilage is flexible w/ gel-like matrix contains collagenous and elastic fibers. - Chondrocytes - Blood/Nerve supply • Three types differ according to type and arrangement of fibers. • Hyaline - Firm and flexible. Ends of bones • Fibrocartilage - Strong. disks • Elastic - Flexible. Ear, epiglottis

10. C) Fibrous Connective Tissue • Made of rows of fibroblasts separated by bundles of collagenous fibers. • Makes up ligaments and tendons

11. Bone Structure • Epiphysis, diaphysis, medullary cavity • Yellow bone marrow • C) Periosteum

13. Bone Growth and Repair • Several different types of cells are involved in bone growth and repair. • Osteoprogenitor cells – unspecialized. • Osteoblasts – bone-forming/matrix secretion. • Osteocytes - mature • Osteoclasts – bone reabsorption • Ossification - bone formation.

15. Remodeling of Bones • Osteoclasts break down bone, remove worn cells, and assist in depositing calcium in the blood. • Osteoblasts take calcium from blood and form new bone.

16. Bone Repair • Fracture repair takes place over a span of several months in a series of four steps. • Hematoma (6-8 hrs) • Fibrocartilaginous callus (3 wks) • Bony callus (osteoblasts, spongy, 3-4 months) • Remodeling (osteoblasts = compact) (osteoclasts = spongy) • Naming of a fracture indicates what kind of break occurred.

21. Bones of the Skeleton • Skeletal Functions. • Support body. • Protect soft body parts. • Produce blood cells. • Store minerals and fat. • Permit flexible body movement.

22. Bone Classification • Bones are classified according to their shape, and whether they occur in the axial skeleton or the appendicular skeleton. • Axial - Midline. • Appendicular - Limbs and their girdles. • 206 total bones in body

24. The Axial Skeleton • The axial skeleton lies in the midline of the body and consists of: • Skull (8 bones) • Hyoid bone. • Vertebral column (33 bones) • Rib cage (12 pairs)

28. The Appendicular Skeleton • The appendicular skeleton consists of bones within the pectoral and pelvic girdles and their attached limbs.

29. Bones of Pectoral Girdle and Arm

30. Bones of the Lower Limb

31. Articulations • Bones are joined at joints. • Cartilaginous joints are connected by hyaline cartilage. • Synovial joints separate the bones by a cavity. • Hinge. • Ball-and-socket.

33. Movements Permitted by Synovial Joints • Angular Movements. • Flexion- Decreases joint angle. • Extension - Increases joint angle. • Adduction - Movement towards midline. • Abduction - Movement away from midline.

34. Movements Permitted by Synovial Joints • Circular Movements. • Rotation - Movement around axis. • Supination - Rotation with palm upward. • Circumduction - Movement in wide circle. • Special Movements. • Inversion(sole inward) and eversion (sole outward). • Elevation (lifting up) and depression (moving down).

36. THE END