Connective Tissue Histology 3rd Lec by Dr Roomi

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HISTOLOGYOF

CONNECTIVE TISSUE

BY

DR. MUDASSAR ALI ROOMI (MBBS, M. Phil.)

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LOOSE CONNECTIVE TISSUE

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DENSE CONNECTIVE TISSUE:

FEATURES:

Close packing of fibers

Fewer cells than loose C.T Lesser ground substance

Less flexible

Resistant to stress

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TRUE OR PROPER CONNECTIVE TISSUE

DENSE CONNECTIVE TISSUE:

according to arrangement of fibers it is of two

varieties:

a. Dense regular connective tissue Tendons

ligaments

aponeurosis

b. Dense irregular connective tissue

Dermis of skin, submucosa of digestive tract

Capsule of liver, spleen and glands

Joint capsules

Heart valves

Perichondrium

Periosteum

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Dense Connective Tissue

contains more numerous

and thicker fibers and far

fewer cells than loose CT.

1. DENSE REGULAR

CONNECTIVE TISSUE

consists of bundles ofcollagen fibers are denselypacked and running parallel

to each other

fibroblasts are thepredominant cell

Function = provide strongattachment between variousstructures

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DENSE REGULAR CONNECTIVE TISSUE

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Tendons: have bundles of collagen fibers.

Aponeurosis: have several superimposed

layers of collagens fibers. Ligaments: just like tendon in histology. White

and yellow (elastic) ligaments.

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APONEUROSIS

Flat and relatively thin

sheet of collagen fibers

e.g. bicipital

aponeurosis

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Yellow elastic ligaments

Examples of yellow elastic ligements:

1. Ligamentum nuchae

2. True vocal cords3. Ligamentum flavum of vertebral column

4. Suspensory ligament of penis.

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DENSE IRREGULAR CONNECTIVE TISSUE:

consists of randomly-arranged collagen fibers and a few fibroblasts

Fewer other cell types

minimal ground substancejust like dense regular C.T

Collagen fibers exhibit random orientation and provide strong

tissue support

Concentrated in areas where resistance to forces from differentdirections is needed

Function = provide strength

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DENSE IRREGULAR CONNECTIVE TISSUE

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FUNCTIONS OF CONNECTIVE TISSUE

To connect the various structures with each othere.g. tendon.

Mechanical support to tissue e.g dermis of skin.

Exchange of nutrients through the ground substance.

Defense function is provided by:

1. Barrier made by the intercellular substance

2. Macrophages

3. Plasma cells

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GROUND SUBSTANCE

The ground substance of the ECM is a highlyhydrated, transparent, complex mixture ofmacromolecules, principally in three classes:

GAGs, proteoglycans, and glycoproteins. The complex molecular mixture of the ground

substance is transparent and rich in bound water.

It fills the space between cells and fibers of

connective tissue and, because it is viscous,

acts as both a lubricant and a barrier to thepenetration of invaders.

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BASEMENT MEMBRANE (Basal Lamina)

The basement membrane is a thin sheet of

extracellular fibers that underlies the

epithelium.

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EM STRUCTURE OF BASEMENT

MEMBRANE

Single central layer,lamina densa (60-300nm thick). It has

densely arranged typeIV collagen fibers.

On either side, laminalucida (10-50nm thick).It contains looselypacked type IV collagenfibers+ GAGs+proteoglycans.

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FUNCTIONS OF BASEMENT

MEMBRANE

1. It binds the epithelium to its connective tissueunderneath.

2. To provide a flexible support to epithelial cells.

3. acts as a mechanical barrier, preventingmalignant cells from invading the deepertissues.

4. It is also essential for angiogenesis.

5. It serves as a molecular sieve or ultrafilter e.g.this property is especially served by theglomerular capillaries.