This document discusses the structure and formation of bone. It describes the different types of bone cells including osteoblasts, osteocytes, and osteoclasts. It explains that compact bone contains Haversian systems with concentric lamellae and Haversian canals containing blood vessels. Spongy bone contains trabeculae. There are two processes of bone formation: intramembranous ossification where bone forms directly in mesenchymal tissue, and endochondral ossification where cartilage is replaced by bone with zones of proliferation, hypertrophy and calcification.

1. BONE
General Histology Lab.
Al-Azhar University –Gaza
Faculty of Dentistry

2. Spongy
bone
Compact
bone

3. Bone cells

4. 1- Osteogenic Cells
(Osteoprogenitor Cells)

5. 2- Osteoblasts
(Bone Forming Cells)

6. Epithelial Like appearance

7. 3- Osteocytes (Mature Bone Cells)

9. 4 - Osteoclasts
(Bone Destroying Cells)

11. 11
Osteoclast
(bone resorption)
osteocyte
Howship’s
lacuna
Osteoblasts
(bone
deposition)
Osteoclast
osteocytes
osteoblasts
osteoclast

12. 12
periosteum
woven
matrix
osteocytes
osteoblasts
bony spicules
osteocytes
Ground Substance
(glycosaminoglycans)
Collagen
(reinforcing)
Bone Mineral
(calcium phosphate)
osteoblasts
osteocytes

13. 13
PERIOSTEUM
bone
Sharpey’s Fibers
(regions of tendon attachment)
Periosteum
compact
endosteum
periosteum
osteoblasts
Decalcified Tibia (transverse section)
compact bone
marrow

19. COMPACT BONE
Volkmann’s
canal
Haversian
canal
interstitial
lamellae
outer
circumferential
lamellae
Haversian
systems
(osteons)
inner
circumferential
lamellae
spongey bone
Ground Bone
Volkmann’s
canal
Haversian system
Haversian canal

20. lamella
canaliculae
Haversian canal
(artery & vein or
capillary)
osteocyte
lacuna
HAVERSIAN SYSTEMS
Ground
Bone
canaliculae

21. osteocyte gap
junction
canaliculu
s
Lacuna
canaliculi

22. HAVERSIAN SYSTEMS AND INTERSTITIAL LAMELLAE
HAVERSIAN SYSTEM
INTERSTITIAL
LAMELLAE

23. HAVERSIAN SYSTEM SEM

24. 24
Compact Bone

27. Membranous Ossification

28. 28
INTRAMEMBRANOUS OSSIFICATION
Mesenchymal
Cells
(connected by
processes)
Collagen and
Matrix
Calcified Bony
Matrix
(trabeculae)
Osteoblasts
Osteoclasts
Osteocytes
Primary
Spongiosa
Skull- frontal, parietal, occipital temporal bones
mandible- jaw
Intramembranous
Ossification
posteoprogentor cells osteoblasts osteocytes
monocytes osteoclasts

29. Thank You

31. 31
ENDOCHONDRAL OSSIFICATION
(base of skull, vertebral column, bones of extremities, long bone
hyaline
cartilage
zone of
proliferation
zone of
maturation
zone of
hypertrophy
zone of pimary
calicification
primary
spongiosa
(resorption of
calicified
cartilage)
secondary
spongiosa
isogenous nests
of chondrocytes
interstitial growth
columns of chondrocytes
(division in one plane)
enlarged (hypertrophic)
chondrocytes
calcified cartilage
degenerate chondrocyte
calificied cartilage
bone matrix
bony trabeculae
mesenchymal cells

32. 32
Endochondral Ossification
 Within cartilage. Interstitial growth. Cells swell,
burst, replace by osteocytes with Ca+

33. 33
Endochondral Ossification
 Secondary ossification - epiphysis
 Articular cartilage and epiphysial plate -