Cartilage+and+Bone+Lab


 * 8 September 2006**
 * Microanatomy Lab – Cartilage and Bone Lab**
 * Dr. Robert Crissman, Ph.D.**

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=**Cartilage**=


 * **Diagnostic Characteristics**: Large round cells, avascular, perichondrium, lots of amorphous extracellular matrix
 * Active secretion of sulfated molecules so staining in extracellular matrix is darker
 * Aggrecan Aggregates made from keratin and chrondriotin
 * Two types of growth:
 * Interstitial Growth
 * Clumping chondroblasts in isogenous groups within the cartilage
 * May not see many fibers because cells are still growing
 * Appositional Growth
 * Two layers in perichondrium: fibrous layer and chondrogenic layer
 * Appositional growth of cartilage occurs in chondrogenic layer
 * No wandering or plasma cells

**Elastic Tissue**

 * Has perichondrium, avascular, large round cells, lots of extracellular matrix
 * Elastic fibers stain darkly, with fibers splitting in acute angles

**Fibrocartilage**

 * Two components of intervertebral disk:
 * Anulus fibrosis
 * Made of fibrocartilage – Collagen Type I
 * Nucleus pulposis – Gelatinous matrix
 * For shock absorption

=**Compact Bone**=


 * Dried specimen have osteocytes removed, leaving holes that have been filled with India ink.
 * Holes are the remaining lacunae
 * Canaliculi can be seen reaching towards the next cell
 * Inside are cellular processes of the osteocyte
 * Limits of individual osteons can be distinguished, and interstitial lamellae
 * Interstitial lamellae are remnants of former osteons and have incomplete parts of Haversian systems
 * Haversian canals are lined by bone lining cells
 * Volkmann’s canal appears like a dumbbell shaped structure without concentric rings of osteocytes
 * Volkmann’s canal runs perpendicularly to bone surface
 * Do not want Volkmann’s canal to run entire length of a bone because if the bone breaks, the indirect damage would kill all the cells in the bone when nutrient supplies are cut
 * Internal remodeling can be observed through osteoclast action
 * Resorbption canal can be found by looking for big holes the size of an osteon without concentric rings
 * Forming osteons look like a hole larger than central canal with a few concentric rings
 * Oldest osteocyte is nearest to the cement line