Your SlideShare is downloading. ×
0
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Histo – bone
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Histo – bone

1,428

Published on

Published in: Health & Medicine, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
1,428
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
78
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Histology of the Bone By: Dr Mohammed Faez
  • 2. Objective of The Lecture • To know about definition of the bone. • To master the basic structure of the bone. • To know about bone matrix and bone cells. • Illustrate and differentiate the three type of bone cells. • To know about the periosteum & endosteum.
  • 3. Bone • Bone is a dense, semirigid, porous, calcified connective tissue forming the major portion of the skeleton. • It consists of a dense organic matrix and an inorganic, mineral component.
  • 4. Bone • Bone is a specialized connective tissue composed of intercellular calcified material, the bone matrix, and three cell types: osteocytes, osteoblasts and osteoclasts • All bones are lined on both internal and external surfaces by layers of tissue containing osteogenic cells endosteum on the internal surface and periosteum on the external surface.
  • 5. Bone Functions • Protects vital organs • Supports soft tissue • Movement • Mineral storage • Blood cell production
  • 6. Microscopic structure of compact bone • The structural unit of Compact bone is the osteon,or haversian system. Each osteon • Is an elongated cylinder • Oriented parallel to the • Long axis of the bone.
  • 7. Microscopic structure of compact bone Osteon System: • A central (Haversian) canal with concentric rings (lamellae) of bone matrix running lengthwise. • Very strong!
  • 8. Microscopic structure of compact bone • Central, or haversian canal carries blood vessels and nerves to all areas of the bone. • Canaliculi tiny canals that radiate outward from the central canals to each lacunae space. • Volkmann’s Canals: canals that run at right angles to the central canals and perforate the shaft of the bone.
  • 9. Microscopic structure of compact bone
  • 10. Osteon Central Canal w/ blood vessels, nerves Lacunae w/ bone cells
  • 11. Compact bone structure
  • 12. Compact bone structure
  • 13. Spongy Bone • Spongy bone contains trabeculae and spicules giving it a honeycomb appearance. • Trabeculae: are irregularly arranged and contain lamellae and osteocytes, but contain no osteons as they receive nutrients from the marrow tissue.
  • 14. Spongy bone histology
  • 15. Bone Matrix • 25% Water • 25% Protein or organic matrix – 95% Collagen Fibers – 5% Chondroitin Sulfate • 50% Crystalized Mineral Salts Hydroxyapatite (Calcium Phosphate) Other substances: Lead, Gold, Strontium, Plutonium, etc. • Combination provides strength and rigidity – Laid down by osteoblasts
  • 16. Bone Matrix • If mineral removed, bone is too bendable • If collagen removed, bone is too brittle
  • 17. Bone Cells 1. Osteoblasts: Bone generating cells “B” means building 2. Osteocytes: Mature bone cells, spider shaped and maintain bone tissue 3. Osteoclasts: Bone destroying cells “C” means chewing
  • 18. Osteoblasts • Osteoblasts are responsible for the synthesis of the organic components of bone matrix (type I collagen, proteoglycans, and glycoproteins). • Osteoblasts depends on deposition of the inorganic components of bone.
  • 19. Osteoblasts • Osteoblasts are exclusively located at the surfaces of bone tissue, side by side, in a way that resembles simple epithelium. • When they are actively engaged in matrix synthesis, osteoblasts have a cuboidal to columnar shape and basophilic cytoplasm. • When their synthesizing activity declines, they flatten, and cytoplasmic basophilia declines.
  • 20. Osteoblasts
  • 21. Osteocytes • Osteocytes, which derive from osteoblasts, lie in the lacunae situated between lamellae of matrix. • Only one osteocyte is found in each lacuna. • Lacunae: spaces occupied by osteocyte cell body
  • 22. Osteocytes
  • 23. Osteocytes
  • 24. Osteoclasts • Osteoclasts are very large and branched motile cells. • Dilated portions of the cell body contain from 5 to 50 (or more) nuclei. • Osteoclasts are derived from the mononucleated cells; (engulf bony material). • Active osteoblasts stimulate osteoclast activity.
  • 25. Osteoclasts Resorption of bone • Ruffled border: where cell membrane borders bone and resorption is taking place. • H ions pumped across membrane, acid forms, eats away bone. • Release enzymes that digest the bone.
  • 26. Osteoclasts
  • 27. Bone Resorption
  • 28. Periosteum • It consists of an outer layer of collagen fibers and fibroblasts. • Bundles of periosteal collagen fibers, called Sharpey's fibers, penetrate the bone matrix, binding the periosteum to bone.
  • 29. Periosteum
  • 30. Endosteum • It lines all internal cavities within the bone and is composed of a single layer of flattened osteoprogenitor cells and a very small amount of connective tissue. • The endosteum is therefore considerably thinner than the periosteum.
  • 31. Periosteum & Endosteum • The principal functions of periosteum and endosteum are nutrition of osseous tissue and provision of a continuous supply of new osteoblasts for repair or growth of bone.
  • 32. Periosteum & Endosteum

×