Anatomy Step I basic Histology Slides



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Anatomy Step I Basic Histology Slides


  1. Chondrogenic Ossification

-2 ways of ossification:

-intramembranous oss.: direct mineralization of matrix secreted by osteoblasts

-chondrogenic oss.: deposition of bone matrix an a preexisting cartilage matrix

-> this takes place in a piece of hyaline cartilage

-responsible for formation of long and short bones

-steps:



  1. formation of bone collar (hollow bony cylinder at mid portion

    • produced by intramembraneous oss.

  1. degeneration at cartilage with cell enlargement & calcification of matrix

    • process begins at diaphysis (blood cells enter here+ osteoclasts+ Osteoproginator cells)

  1. osteoblasts adhere to calcified matrix & produce layers of primary bone

  2. creation of 2nd ossification centers in epiphysis

-> ossification centers produce cavities that are filled with bone marrow

5 zones of chondrogenic ossification

  1. Resting Zone:

  1. Proliferate Zone:

    • chondrocytes divide & form columns

  1. Hypertrophic cartilage Zone:

  1. Calcified cartilage Zone:

  1. Ossification Zone: appearance of chondrogenic bone tissue

  • -formation of blood capillaries. & osteoprogenitor cells (-> osteoblasts)



  1. Bone (cross ground)

= specialized CT composed of intercellular calcified material (bone matrix)

  • 3 cell types:

    1. osteoclasts (multinucleated giant cells, veabsorbtion and remodeling of bone tissue)

    2. Osteoblasts (synthesize organic components of matrix derived from osteoprogenitor cells later become osteocytes)

    3. Osteocytes (found in lacunae within the matrix) -> communicate with capillaries via canaliculi

  • Bone surfaces:

    1. Endosteum (lining inner surface)

      1. CT & osteoprogenitor cells

    2. Periosteum (lining outer surface)

      1. Sharpeys fibers (= collagen fibers) bind periosteum to bone

      2. Composed of osteoprogenitor cells

    3. Endo- and Periosteum supply bone with nutrients & new Osteoblasts

  • Bone tissue:

    1. Haversian system (osteon)

      1. Lamellae (parallel collagen fibers) -> interstitial outer & inner circumferential

      2. Lacunae (withosteocytis inside lamellae)

      3. Central vascular canal

      4. Cementing substance

      5. Haversian canal (parallel)

      6. Volkmann’s canal



  1. Blood smear (MGG)

Blood cells

  • Erythrocytes

    • Nucleated, biconcave, 7.5 micrometer in diameter

    • Outer thickness 2.8 micrometer

    • Inner thickness 0.8 micrometer

    • Normal value:

      • 3.9-5.5 Milton /microliter in women

      • 4.1-6 million/microliter in men

    • Young RBC = reticulocyte

    • Lifespan ~120 days

  • Leukocytes (6000-8000 per microliter)
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