BONE
SSN Histology
The Basics
• Specialized connective tissue:
– mineralized matrix (hydroxyapatite)
• Type I Collagen; Proteoglycans; Noncollagenous Glycoproteins
• Functions:
– Mechanical support
– Calcium homeostasis
– Encloses bone marrow
Cells
Osteoblasts = osteocyte progenitors;
secrete ground substance for osteoid
Lab 5, Slide 30
Cells
Osteocytes = mature, non-dividing bone
cells; enclosed in calcified bone matrix
Cells
Osteoclasts = remodeling/ resorption by
using lysosomal enzymes
Osteoclasts:
Cells
Limited bone resorption
Active bone resorption
Mature vs. Immature Bone
Mature (Lamellar)
Compact (Cortical)
•w/ Haversian systems
Spongy (Cancellous)
•w/ trabecular appearance
Mature vs. Immature Bone
Immature Bone (Woven)
•Nonlamellar
•Found in fetus or following a fracture
Appositional vs. Interstitial
• Appositional = bone growth on pre-existing
bone surface
– Note that bone tissue only undergoes appositional
• Interstitial = bone growth via new cartilage
formation within pre-existing cartilage mass
– Note that it is cartilage that undergoes interstitial
• Long Bone Growth:
– WIDTH --> Appositional (bone)
– LENGTH --> Interstitial (cartilage)
Endochondral vs.
Intramembranous
Endochondral
Intramembranous
Endochondral Ossification
Endochondral Ossification
Zone of
Proliferation
Zone of Reserve
Cartilage
Endochondral Ossification
Zone of Hypertrophy
Zone of Proliferation
Endochondral Ossification
Zone of Resorption
Zone of Calcification
Preparation of Bone Samples
Ground Bone
Preparation of Bone Samples
Ground Bone
Preparation of Bone Samples
Decalcified Bone
Final Thoughts….
• Let staining properties guide you
• Note cellularity; compare size, color, shape,
relative quantity of cells
• Haversian = central to osteon
• Volkmann’s = perpendicular
• Think of bone as specialized connective tissue;
always in a dynamic state
• Long bones = endochondral
• Parietal bones = intramembranous
• Mnemonic for Endochondral:
Real Players Have Cool Rides
Question 1. . .
Panel A
Panel B
Questions 2 & 3. . .
Figure A
Figure B
Questions 4 & 5. ..
Panel A
Panel B
Question 6. . .