This document discusses the anatomy of bone, including its structure, function, classification, development, and blood supply. It describes bone as a composite connective tissue made up of organic components like bone cells and collagen and inorganic components like calcium crystals. It classifies bone tissue into woven bone, lamellar bone, cortical bone, and cancellous bone. Bone development occurs through either intramembranous or endochondral ossification. Finally, it outlines the dynamic process of bone remodeling carried out by osteoblasts, osteoclasts, and the blood supply to bone.

1. ANATOMY OF BONE
STRUCTURE,FUNCTION,CLASSIFICATION,
DEVELOPMENT AND BLOOD SUPPLY OF BONE.
Presenter:Dr.Siddique H.Ranna
PG Student
Moderator:Dr.Pranjal Tahbildar
Prof&HOD

2. Introduction
BONE
Composite connective tissue, made up of
1.Organic components
Bone cells,&collagen matrix
Non collagenous protein
Musculopolysaccharides
2.Inorganic components
 Calcium crystals,CaPO4
 Trapped Ions:citrates,Na,K

3. Chemical Composition of Bone
Organic-25% Inorganic-65% Water-10%
*crystalline hydroxyappetite
Bone cells-4% Intracellular *amorphous CaPo4
matrix-20% *trapped ions
*Osteoblast *Collagen citrates
*Osteoclast *protein peptides Na.K,Mg,F *In crystals
*Osteocytes *proteoglycans *extracellular
*lipids *cellular

4. FUNCTIONS OF BONE
1.MECHANICAL
*Protection
*Gives structure
*Facilitates movement
*Facilitates hearing
2.HEAMOPOITIC- *Produce Blood Cells
3.METABOLIC
*Mineral Storage
*Growth factor storage(IGF,TGF,BMP,etc)
*Fat storage
*Endocrine (FGF-23,Osteocalcin

5. Classification of Bones on the
Basis of Shape
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.1

9. Types of Bone Tissue
1.woven Bone 2.lamellar bone
A. Cortical or Compact bone B.Cancellaous
or spongy bone

10. 1. WOVEN BONE OR IMMATURE
BONE
• Collagen fibers run in various direction, less
organized than lamellar bone
• Found in early phase of bone development,
bone remodeling or fracture healing
• Mineralized but less biomechanical strength
than lamellar bone
• This type of bone replaced by lamellar bone
latter.

11. 2. LAMELLAR BONE OR MATURE
BONE
Collagen fibers are oriented in layers(lamellae)
Within each layer collagen fibers are parallel.
Fiber direction differ from layer to layer.
It provides tensile strength to the bone
Osteocytes are located at the borders between
these lamellae

12. A. Cortical or compact bone :
Constitute 80% of bone mass.
But only 20% of bone surface.
 consists of numerous cylindrical units known as
Haversian systems.

13. B. Cancellous or spongy trabecular
bone :
Constitutes 20% of the bone mass but 80% of bone surface
Bones in the axial skeleton( vertebral bodies,ribs,iliac crest, ends of long bones)
Spongy bone is sponge like with numerous cavities
 loose network of bony plates called trabeculae
Each trabeculae is made up of number of lamellae
Between lamellae, lacuna containing osteocytes present
trabeculae are arranged generally along the line of maximum stress
 devoid of Haversian system

14. Copyright 2009 John Wiley & Sons, Inc.
Histology of spongy bone

15. Ossification of Bone
Intramembranous Enchondral
form flat bones form long bones
Begins at 8wk begins at 2 months
Develops from fibrous develops from carti-
membrane -lage model

16. Intramembranous Ossification
(prenatal)
Mesenchymal cells create
fibrous CT framework for
ossification
Some mesenchymal cells
differentiate into osteoblasts
in an ossification center
Osteoblasts secrete bone matrix, osteoid

17. Intramembranous Ossification
Mineralization and
calcification of osteoid
Trapped osteoblasts become
osteocytes

18. Intramembranous Ossification (prenatal)
Osteoid accumulates in
between embryonic
blood vessels, creating
trabeculae of woven
bone.
Mesenchyme on bone
face condense and
differentiate into
periosteum

19. Intramembranous Ossification (prenatal)
A bone collar of thickly woven
osteoid forms around
trabeculae and ossifies into
compact bone
Spongy bone (diploë)
cavities made up of
trabeculae fill with red
marrow created from
vessels (vascular tissue)
overview

20. Endochondral Ossification
Bone collar formed around
diaphysis by osteoblasts
located on inner side of
periosteum

21. Endochondral Ossification
Cartilage in primary
ossification center calcifies,
then the cells die and
cavities form (cavitates)
Bone collar provides stability
during cavitation
Cartilage elsewhere continues to
elongate

22. Endochondral Ossification
Periosteal bud (lymph, blood
vessels, nerves, red marrow,
osteoblasts and osteoclasts)
enters cavity and builds
spongy bone

23. Endochondral Ossification
Osteoclasts dissolve spongy
bone to create medullary
cavity
Secondary Ossification Center
forms in epiphysis

24. Endochondral Ossification
Secondary Ossification Center
does NOT calcify. Spongy bone
retained.
Hyaline only remains on
epiphyseal surface (articular
cartilage) and at diaphysis and
epiphysis junction, to form the
epiphyseal plates.

25. Growing taller
throughout childhood!

27. When does lengthening stop?
• End of adolescence - lengthening stops
– Chondrocytes stop mitosis.
– Plate thins out and replaced by bone
– Diaphysis and epiphysis fuse to be one bone
• Epiphyseal plate closure (18 yr old females, 21 yr old
males)
• Thickening of bone continuous throughout life

28. Bone is Dynamic!
Bone is constantly remodeling and recycling
• Coupled process between:
1. Bone deposition (by osteoblasts)
2. Bone destruction/resorption (by osteoclasts)
• 5-7% of bone mass recycled weekly
• All spongy bone replaced every 3-4 years.
• All compact bone replaced every 10 years.
Prevents mineral salts from crystallizing; protecting against brittle
bones and fractures

29. Copyright 2009 John Wiley & Sons, Inc.
Bone tissue cell types
• Osteoprogenic cells – unspecialized stem
cells
• Osteoblasts – bone builders
• Osteocytes – mature bone cells derived
from osteoblasts
• Osteoclasts – bone ‘breakers’ are
multinucleate

30. Osteoblast Differentiation

31. Multinucleated cell the originates from hematopoietic stem cells
Characterized by possessing tartrate-resistant acid phosphatase (TRAP) within its
cytoplasmic vesicles and vacuoles
Found against bone surface in hollowed depressions called Howship’s lacunae
RANK: receptor-activated nuclear factor κB and RANKL: RANK ligand

32. Copyright 2009 John Wiley & Sons, Inc.
Blood supply of a long bone

33. THANK YOU
ALL