Histology Notes

1. BONE IS A SPECIALIZED FORM
OF CONNECTIVE TISSUE
 MINERALIZATION OF MATRIX
 VASCULARITY
 DYNAMIC

2. COMPONENTS
 CELLS
OSTEOGENIC
OSTEOBLAST
OSTEOCYTE
OSTEOCLAST
 MATRIX
ORGANIC
INORGANIC

3. OSTEOGENIC CELLS
 STEM CELLS
 MESENCHYMAL
 DIVISION & PROLIFERATION
 FLATTENED, ELONGATED CELLS
 EXTERNAL & INTERNAL SURFACES OF
BONE (PERIOSTEAL, ENDOSTEAL, HAVERSION
CANAL)

4. OSTEOBLAST
 BONE FORMING CELLS
 SINGLE LAYER ON SURFACES OF
BONE(MATURING OR REMODELLING)
 ACTIVE OR INACTIVE
 FUNCTIONS
 PRODUCE MATRIX -------OSTEOID
 DEPOSITION OF INORGANIC COMPONENETS
 HORMONAL REGULATION OF BONE
RESORPTION (RECEPTORS PTH & VIT D3)

5. OSTEOCYTE
 MAJOR CELLS OF MATURE BONE
 TRAPPED OSTEOBLAST
 STELLATE CELLS WITH PROCESSES
 LACUNAE, CANLICULI
 LIGHTLY BASOPHILIC WITH FEW
ORGANELLES
 MATRIX TURNOVER, BONE SENSOR

6. OSTEOCLAST
 PHAGOCYTIC, MONOCYTIC
 ACTIVE RESORPTION SITE (HOWSHIP LACUNAE)
 MULTINUCLEATED, LIGHTLY BASOPHILIC
 E/M 3 ZONES
ZONE I RUFFLED BORDER CLEAR ZONE
ZONE II MITOCHONDRIA & LYSOSOMES
ZONE III NUCLEI rER, GOLGI complex

8. MATRIX
 ORGANIC COLLAGEN FIBERS
PROTEOGLYCANS
GLYCOPROTEINS
 INORGANIC MINERAL SALTS

9. COLLAGEN FIBER
 30—40%
 TYPE I
 OSTEOBLAST
 FASICLES OR GROUPS CLOSELY LINKED ( //, at an
angle) makes bone STRONGER & INERT
 GAPS BETWEEN TROPOCOLLAGEN LARGER
CONTAINING CRYSTALS ( 2/3 OF MINERAL
CONTENT)
 ASSOCIATED WITH OSTEO NECTIN
 FUNCTIONS MECHANICAL STRENGTH, NUCLEATION SITE,

10. GLYCOPROTEINS
 OSTEONECTIN
PHOSPHORYLATED GLYCOPROTEINS
ADHESION OF COLLAGEN FIBER TO CRYSTALS &
OSTEOCYTES
 OSTEOCALCIN
Ca DEPOSITION

11. MINERAL SALTS
 60-70%
 Ca, phosphate, Mg, Zn Na
 NEEDLE SHAPED CRYSTALS (HYDROXY APATITE )
 CRYSTALLINE & NONCRYSTALLINE
 // TO LONG AXIS OF FIBERS
 GAPS B/W TROPOCOLLAGEN

12. PREPARATION OF TISSUE
 DECALCIFIED
REMOVAL OF MINERAL CONTENT
THROUGH CHELATING AGENTS
EMBEDDED, SECTIONED, STAINED
 GROUND BONE

13. CLASSIFICATION OF BONE
arrangements of different components
 LAMELLAR
COMPACT
SPONGY
 NON LAMELLAR PRIMARY BONE

14. PRIMARY BONE
 IMMATURE, NON LAMELLAR,WOVEN BONE
 TEMPORARY, EMBRYONIC DEVELOPMENT
 ADULTS SPECIFIC LOCATIONS
 NON LAMELLAR
 LOW MINERAL CONTENT
 HIGH CONTENT OF OSTEOCYTES

15. SECONDRY BONE
 LAMELLAR, MATURE, ADULT
 LAMELLAE OF MATRIX
 COMPACT & SPONGY

16. COMPACT BONE
 DIAPHYSIS OF LONG BONE
 MEDULLARY CAVITY
 PERIOSTEUM & ENDOSTEUM
(SHARPEYS FIBER)
 OUTER CIRCUMFERENTIAL LAMELLAE
 HAVERSION SYSTEM
 VOLK MAN CANAL
 INTERTISTIAL LAMELLAE
 INNER CIRCUMFERENTIAL LAMELLAE

17. COMPACT BONE
 OSTEON HAVERSION SYSTEM
 HAVERSION CANAL
 CONCENTRIC LAMELLAE OF MATRIX
 SEPARATED BY THIN PLATES OF
MATRIX HIGH MINERAL & LOW ORGANIC
 LACUNAE & CANALICULI
 CEMENT LINE

21. Spongy bone
 Ends of long bone
 LAMELLAR Same arrangement of cells & matrix
 Bony trabeculae
 Marrow spaces lined by endosteum
 Diffusion

23.  RICKETS
 OSTEOMALACIA
 OSTEOPOROSIS
 OSTEOPETROSIS
 VITAMIN D, A, C

24. OSSIFICATION

25. INTRAMEMBRANOUS (direct
mineralization of highly vascularized C.T)
 FLAT BONES MAXILLA, MANDIBLE,CLAVICLE
 PRIMARY CENTER OF OSSIFICATION
AGGREGATION & VASCULARIZATION
DIFFERENTIATION (POLARITY)
OSTEOID
CALCIFICATION
 SEVERAL SUCH GROUPS FORMING STRIPS OF MATRIX FUSE
 PENETRATION BY BLOOD VESSELS
 SPONGY BONE THE PROCESS SLOWS DOWN THICKENING OF
TRABECULAE & NARROWING OF VASCULAR SPACES
 IN COMPACT BONE PRIMARY & SECONDRY OSTEONS
 PERIOSTEUM & ENDOSTEUM

27. PARTS OF A DEVELOPING BONE
 EPIPHYSIS
 DIAPHYSIS
 METAPHYSIS

28. INTRACARTILAGENOUS

31. INTRACARTILAGENOUS
DIAPHYSIS
 SHORT & LONG BONES
 MINIATURE CARTILAGE MODEL
 PRIMARY CENTER OF OSSIFICATION
PRIMARY AREOLAE
 PERIOSTIUM BONE COLLAR
 PERIOSTEAL VASCULAR BUDS
SEC. AREOLAE (TRABECULAE CALCIFIED CARTILAGE & AN
OUTER LAYER OF BONE)
 PRIMITIVE MEDULLARY CAVITY (OSTEOCLASTIC EROSION)
 MATURE BONE MARROW
 DEVELOPMENT OF HAVERSION SYSTEM

32. HAVERSION SYSTEM
 VASCULARIZATION
 TUNNEL
 DEPOSITION OF BONE

33. EPIPHYSEAL PLATE
 ORGANIZED REGION OF RAPID GROWTH
BETWEEN EPIPHYSIS & DIAPHYSIS
 INTERSTITIAL & APPOSITIONAL GROWTH
 ZONE OF CARTILAGE GROWTH
 CARTILAGE TRANSFORMATION
 OSSIFICATION
 REMODELLING

35. EPIPHYSIS
 APPOSITIONAL GROWTH
 INTERSTITIAL GROWTH
 SECONDRY CENTRE OF
OSSIFICATION
 RADIAL ORGANIZATION OF ZONES

36. CALCIFICATION
 > CONC OF Ca BINDING WITH
OSTEOCALCIN
 OSTEOBLAST secrete ALK. PO4
 CLEAVES PO4 FROM MATRIX
 CRYSTALLISATION OF CaPO4