A-Connective_tissue1-16-12-14.pdf

CONNECTIVE TISSUE

Dr. Archana Rani

Associate Professor

Department of Anatomy

KGMU UP, Lucknow

20.11.2014

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

B. Free cells (extrinsic cells)

5.Macrophage (histiocyte)

6. Mast cell

7. Plasma cells

8. Leucocytes

Mast cell Mesenchymal cell

Plasma cell Adipocyte

Fibroblast

Fibroblast 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)

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

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

. Granulocytes-

Neutrophils

Eosinophils

Basophils

. Agranulocytes-

Lymphocytes

Monocytes

Neutrophil Eosinophil

Lymphocyte Basophil

Monocyte

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 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

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. diFiores 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