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Cells of connective tissue proper

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									Connective tissue


         Structure

          Function
Extracellular matrix

1.   Ground substance
2.   Fibers (collagen, reticular, and elastic)
    Collagen fibers
    Reticular fibers
    Elastic fibers
Fibroblast

the predominant cell type, are responsible for
   synthesis of collagen, elastic and reticular
   fibers, and much , if not all, of the ground
   substance .
Morphology : appear spindle-shape with their
   numerous flattened processes and oval
   nuclei. Constitute the major cellular
   component.
Fibroblast
Macrophage (histocytes)

     are derived from monocytes in bone
       marrow
Morphology : irregular shape, smaller,
  darker, and denser than those of
  fibroblast with oval nuclei.
Mast cells

    located in the vicinity of blood
      vessels, may be recognized by
      their size.
Morphology : round, large, centrally
  located nuclei, numerous small
  granules in their cytoplasm.
Fat cells (adipocytes)

     may form small clusters in loose
       connective tissue they store lipids and
       form adipose tissue, which protects ,
       insulates and cushions organs of the
       body.
Morphology : resembling round ,eccentric
  nucleus, empty spaces bordered by a thin
  rim of cytoplasm may also be present.
Fat cells (adipocytes)
plasma cell

      are the major cell type present during
        chronic inflammation
Morphology : small, round cells with round ,
acentric nuclei, whose chromatin network
   presents      a    clockface      (cartwheel)
   appearances.
Also lymphocytes , neutrophils, and occasional
eosinophils also contribute to the connective
   tissue
Connective tissue types:

I. Embryonic connective tissue:
A) Mesenchymal connective tissue
Appearance : the matrix empty-looking , contain fine
  reticular fibers. Small blood vessels are evident.
Mesenchymal cells are present , stellate to spindle-
  shape , have processes that touch one another . pale
  scanty cytoplasm with large clear nuclei. Indistinct
  cell membrane.
B) Mucous connective tissue.


Appearance        :when      compared      with
   mesenchymal C.T., the intercellular space
   is filled with coarse collagen bundles ,
   irregularly arranged , matrix is jelly- like
   material.
Fibroblast , consist the major cellular
   component. these cells are resemble or
   identical with mesenchymal cells when
   viewed with a light microscope.
II. Connective tissue proper :


A. Loose ( Areolar) connective
  tissue
Appearance : Slender bundles of collagen
  fibers are intertwine by numerous thin,
  straight , long, branching elastic fibers
  embedded in a watery matrix. reticular fibers
  , also present , are usually not visible in
  section stained with hematoxylin and eosin.
A. Loose ( Areolar) connective
tissue

The most common cell types are
 fibroblasts, macrophages, mast cells,
 occasionally fat cells and in some
 subepithelial connective tissue ( lamina
 propria) of intestines, plasma cells and
 leukocytes are commonly found.
B) Reticular connective tissue .

   Appearance : reticular fibers constitute the
    major portion of the intercellular matrix with
    use of a sliver stain.
   Reticular cells are found only in reticular C.T.
    they are stellate in shape they possess large
    , oval, pale nuclei, and their cytoplasm is not
    easily visible with light microscope.
C) Adipose tissue

Appearance : Unlike other connective tissue , adipose
   tissue is composed of adipose cells so closely
   packed to gather.
Groups of fat cells are subdivided into lobules by thin
   sheaths of loose connective tissue septa housing
   mast cell, endothelial cells of blood vessels.
Each fat cell is invested by reticular fibers, which , in
   turn , are anchored to the collagen fibers of
   connective tissue septa.

								
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