Connective tissue
Structure
Function
Extracellular matrix
1.
2.
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Ground substance
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 spindleshape , 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 .
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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.