Connective tissue

20.11.2014
CONNECTIVE TISSUE
Dr. Archana Rani
Associate Professor
Department of Anatomy
KGMU UP, Lucknow
CONNECTIVE TISSUE
INTRODUCTION
Connective tissue serve as a connecting link
for binding, supporting and strengthening
all other body tissues together.
CONNECTIVE TISSUE
• GENERAL FEATURES
1. Cells
2. Matrix
-Fibres
-Ground substance
CONNECTIVE TISSUE
• Cells
• Fibres
• Ground substance
Cells of Connective Tissue
A. Fixed cells (intrinsic cells)
1. Fibroblast
2. Mesenchymal cells
3. Adipocyte
4. Pigment cells
Mast cell
Mesenchymal cell
B. Free cells (extrinsic cells)
Fibroblast
5.Macrophage (histiocyte)
6. Mast cell
7. Plasma cells
8. Leucocytes
Plasma cell
Adipocyte
Fibroblast
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Most commonly seen ( in all types of connective tissue)
Fusiform with slender cytoplasmic process
Large oval nucleus
Responsible for fiber production
Old (inactive) cells are fibrocytes
Contractile cells are myofibroblasts
More at sites of wound healing
Fibroblast
Adipocytes (Fat cells)
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Signet-ring like appearance
Store lipid
Appears as empty space
Do not undergo cell
division
• May occur singly as in
loose areolar tissue
• May occur in groups as in
adipose tissue
Mesenchymal cells
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Undifferentiated cells
Stellate in shape
Cytoplasmic process
Pluripotent cell
Along blood vessels
Macrophages (Histiocytes)
• Free and Fixed type
Fixed Cells (histiocytes)• Irregular Shape
• Short branching processes
• Dark indented eccentric
nucleus,
• Derived from monocyte
• Involved in phagocytosis
• Fused to form giant cell.
Free Cells- rounded, absence
of processes
Plasma cells
• Oval basophilic cells
• Eccentric nucleus
• Heterochromatin as
cartwheel nucleus
• Derived from B lymphocyte
• Produces immunoglobulin
• Antibody collected as
Russell body
• Present in respiratory tract
and gastrointestinal tract
Mast cells
• Round or fusiform shaped
• Packed with coarse granules
• Present in serous membranes
• Mostly along blood vessels
• Show Metachromasia
• Granules have histamine and
heparin
Leucocytes
. GranulocytesNeutrophils
Eosinophils
Basophils
. AgranulocytesLymphocytes
Monocytes
Neutrophil
Lymphocyte
Monocyte
Eosinophil
Basophil
Leucocytes
Collagen Fibres
• White coloured when fresh
• Do not branch
• Found in abundance in bone,
cartilage, tendon & ligament
• Strong, flexible & inelastic
• Present in bundle
• Collagen protein form fibres
• Fibres are composed of fibril
formed by microfibrilar subunits
• Micro fibrils are made up of
tropocollagen
• Synthesized by fibroblast
Types of Collagen fibre
• Type 1-bones & tendons
• Type 2-cartilage (hyaline & elastic)
• Type 3-reticular fibres
• Type 4-basement membrane
• Type 5-blood vessels
Synthesis of Collagen fibre
Amino acids
Procollagen
Three chains
Tropocollagen
Collagen
Elastic fibres
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Very thin but strong
Composed of elastin protein
Branch and anastomose freely
Can be stretched
Run singly & branch forming
network in loose areolar tissue
• In bundles, found in ligamentum
flava & ligamentum nuchae
• Synthesized by fibroblast
• Found in skin, ligamentum flava
& nuchae and large arteries
Reticular fibres
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Fine delicate strands
Immature collagen fibre (type -3)
Synthesized by fibroblasts
Provide support and strength
Framework of lymphoid tissue
In organ capsules of liver, kidney
& endocrine glands
• Stained by silver salts
(argyrophilic)
Ground substance
• Mixture of glycoproteins & proteoglcans
• Proteoglycans (glycosaminoglycans)hyaluronic acid, chondroitin sulphate, heparan sulphate, keratan
sulphate, dermatan sulphate
• Glycoprotiens- fibronectin (dermis), chondronectin (cartilage),
laminin (basement membrane)
• Colourless
• Highly hydrated
• Provides medium through which substances are exchanged
between blood and cells
Classification of Connective tissue
1. Embryonic connective tissue:
Mucus (umbilical cord)
Mesenchymal (developing embryo & fetus)
2. Connective tissue proper:
Loose connective tissue (Areolar tissue)
Adipose tissue
Reticular tissue
Dense connective tissue
Classification (contd…..)
Dense connective tissue:
Irregular dense connective tissue
Regular dense connective tissue
Elastic connective tissue
3. Specialized connective tissue:
Bone
Cartilage
Blood
Loose connective tissue
Loose connective tissue
Dense irregular connective tissue
Dense regular connective tissue
Dense regular connective tissue
Adipose tissue
References
1. diFiore’s Atlas of Histology with functional
Correlations, 12th Edition.
2. Essentials of Anatomy for Dentistry
Students,1st Edition.
3. Textbook of Histology, 3rd Edition.
MCQ
• Most common type of connective tissue cell is:
1. Mast cell
2. Plasma cell
3. Fibroblast
4. Mesenchymal cell
MCQ
• Cartwheel appearance of nucleus is a feature
of:
1. Macrophage
2. Mast cell
3. Plasma cell
4. Pigment cell
MCQ
• Metachromasia is a feature of:
1. Mast cells
2. Adipocytes
3. Macrophages
4. Mesenchymal cells
MCQ
• The important feature of collagen fibre is:
1. Branched
2. Elastic
3. Anastomose freely
4. Present in bundles
MCQ
• The framework of spleen is made up of:
1. Plasma cells
2. Mesenchymal cells
3. Elastic fibres
4. Reticular fibres