Cartilage

1. Cartilage Skeletal cartilage Mostly water. No nerves or blood vessels Periochondrium Basic components Chondrocytes Lacunae Extracellular matrix

2. Hyaline Cartilage Flexible and resilient Articular cartilages Costal cartilages Respiratory cartilages Nasal cartilages

3. Elastic & Fibrocartilage Elastic cartilage Elastic fibers External ear & Epiglottis Fibrocartilage Compressible & great tensile strength Thick collagen fibers Menisici & intervertebral discs

5. Growth Appositional Growth Interstitial Growth Usually ends during adolescence. Calcified cartilage is not bone.

6. Bone Classification 206 bones in the human body. May vary. Axial Skeleton Appendicular skeleton Classified according to shape. Long Bones—shaft & 2 ends. Bones of the limbs. Short Bones—cube shaped. Wrist & ankle bones. Sesamoid Bones—sesame seed shaped. Within tendonds. Patella. Flat Bones—Thin, flattened, & curved. Sternum & bones of the skull. Irregular Bones—complicated shapes– vertebrae & hip bones.

7. Functions of Bones Support Protection Movement Mineral Storage—Heavy metals. Hematopoiesis

8. Bone Structure Bones are organs. Compact Bone Spongy Bone Trabeculae—Red Marrow Long Bone Structure Diaphysis Medullary cavity Yellow bone marrow Epiphysis Articular cartilage Epiphyseal line—epiphyseal plate Periosteum Fibrous layer Osteogenic layer Osteoblasts Osteoclasts Endosteum Internal Osteoblasts & Osteoclasts

10. Bone Structure Diploe—internal layer of spongy bone. Red Marrow—in cavities of spongy bone of long bones & diploe of flat bones. In adults, most hematopoeisis happens in the heads of the humerus & femur and the sternum & hip bones.

11. Microscopic StructureCompact Bone Osteon or Haversian System Cylinder oriented parallel to the long bone structure. Like a weight-bearing column. Composed of matrix tubes called lamella. Layed down the rings of a tree. Lamella Collagen fibers run in opposite directions Resists twisting. Haversian Canal Volkmann’s canals Osteocytes Lacunae Canaliculi Connect osteocytes to each other & to the blood supply.

13. Spongy Bone Trabeculae Aligned to reduce stress Canaliculi Osteocytes Lamellae—irregularly arranged

14. Composition of Bone Osteoid—organic 1/3 of matrix Proteins & collagen fibers Hydroxyapatites—inorganic Calcium phosphates Hardness Bone Markings Passageways Tendon/ligament/or muscle connections See Table on Next Slide

15. Osteogenesis & OssificationIntramembranous Ossification

17. Endochondral Ossification—Most Bones form this way

19. Bone Growth Do some bones grow throughout life? Epiphyseal Plate Side abutting the shaft—cell division—push epiphysis away from the diaphysis. Transformation Zone—Calcification. Osteogenic Zone—marrow cavity formation Epiphyseal plate closure Appositional Growth--Width

21. Bone Growth & Remodeling Hormonal regulation Growth hormone Thyroid hormones Sex hormones Gigantism Dwarfism 5-7% of bone mass is recycle each week. Remodeling Some are remodeled more that others. Bone deposit—injury or stress. Osteoid seam—unmineralized seam of matrix. Calcification front. Resorption Osteoclasts Lysosomal enzymes acids

22. Calcium ion regulation Negative feedback Parathyroid Hormone (PTH) Stimulates Osteoclasts. Raises blood calcium levels. Calcitonin (from the thyroid)—Encourages calcium deposition. Reduces blood calcium levels. Homeostasis

24. Mechanical Stress Gravitation Mechanical Stress Electrical Impulses

25. Repair of Fractures Types of fractures Nondisplaced Displaced Complete Incomplete Linear---parallel to long axis Transverse—perpendicular to long axis. Open closed Reduction—realignment Closed reduction Open reduction—pins & wires used. 6-8 weeks healing time

26. Bone Repair

28. Bone Disorders, Etc… Osteomalacia Rickets Osteoporosis Causes Insufficient exercise. Diet poor in calcium & protein. Abnormal vitamin D receptors. Smoking Hormone-related conditions Treatments Calcium supplements HRT therapy New drugs Fluoridated water Electrical stimulation Ultrasound Free vascular fibular graft. Bone substitutes