1. Histology of Bone and Cartilage Dr. Sama ul Haque

2. Understand the histology of bone. Understand the histology of cartilage. Objectives

3. Composition of Bones Collagen: chief organic constituent (protein) Inorganic Calcium Salts: Vitamin D essential for absorption

4. A Chemical Analysis of Bone

5. Cells Osteoblasts: bone building, bone repairing cells in the periosteum and synthesize new matrix (Osteogenesis) Osteocytes: osteoblast embedded within the bone matrix (mature bone cells) Osteoclasts: cells that cause absorption of bone or dissolve bone matrix (Osteolysis)

6. Periosteum Dense, fibrous membrane covering bone Contains blood vessels Essential for bone cell survival and bone formation Endosteum

7. Histological or Microscopically Compact bone (dense) Basic unit of compact bone is an osteon. Osteocytes within lacunae arranged in concentric circles called lamellae. This surround a central canal; complex is called Haversian system. Weight Bearing.

8. Histological or Microscopically Spongy bone (cancellous) Contains trabeculae Found at ends of Long Bones, Ribs, Sternum, Hips, Vertebrae, Cranium Web-Like Arrangement Low Stress Areas Where Weight of Bone Would Be a Problem.

9. Compact and Spongy Bone

13. Osteoblasts and Osteocytes

14. Lacunae and Canaliculi Communication

15. Periosteum and Endosteum

16. Mature Bone (Compact)

17. Mature Bone (Spongy)

18. Osteon Lacunae (L) Canaliculi (C) Osteocytes (O)

19. Cartilage  Type of Dense connective tissue ( Cells and fibers)  Perichondrium ( Fibro-vasculo-cellular membrane)  Cells = Characterized by Rigid with flexibility and Resilience.  Avascular  Nerves and lymphatics are absent  Cells (Chondroblasts and chondrocytes)  Matrix => Connective tissue fibers (Collagen, Elastin)

21. Hyaline Cartilage  Hyaline (Glass)  Commonest form  Bluish white, translucent and homogenous in appearance with collagen fibers. Sites: => Articular cartilage => Costal cartilage => Tracheal cartilage  Ossifies to form bone in young age

25. Hyaline Cartilage and Perichondrium

27. Elastic Cartilage  Yellow; Elastin fibers  More elastic than hyaline  Sites: => Pinna of the ear => Epiglottis => Auditory tube  Never o ssifies

29. Elastic Cartilage

30. Fibro-cartilage  White, Opaque with collagen fibers  Sites => Intervertebral disc => Intra articular disc => Menisci  Ossifies in old age

32. Collagen (c) Fibrocartilage

33. Cartilages

34. Thank you