CONNECTIVE TISSUE

CONNECTIVE TISSUE

Connective tissue is one of the basic tissues which gives structural and metabolic support to

the organ and other tissue of the body.

It connects other tissues.

Functions

• Support Structural & Mechanical• Packing Fills spaces, Shape to the

organ• Storage Adipose tissue: energy

Loose areolar CT: water & Electrolytes• Transport Medium for Nutrients &

Metabolic wastes• Repair Fibroblasts:matrix and fibres• Defense Cells: Phagocytosis or

Antibodies

CONNECTIVE TISSUE• GENERAL FEATURES

• 1. Cells 2. Matrix -Fibers -Ground substance

CONNECTIVE TISSUE

Major constituent- Extracellular Matrix

Strength

Cells of Connective Tissue • A. Fixed cells (intrinsic cells) 1.Fibroblast &

Fibrocytes 2. Mesenchymal cells 3. Adipocyte

4. Fixed macrophages• B. Free cells (extrinsic

cells/Wandering Cells) 4.Free Macrophage 5. Mast cell 6. Plasma cells 7. Leucocytes

Function

• Fixed Cells: Production & Maintenance of Extracellular Matrix.• Free Cells:Tissue reaction to injury

or invasion of Microorganisms.

Fibroblast

• Most commonly seen• Fusiform with slender cytoplasmic process• Large oval nucleus,• Responsible for fiber production• Old cells are fibrocyte, • Contractile Cells are myofibroblast

Fibroblast

Adipocytes

• Store lipid• Appears as empty

space• Incapable to division• Aggregate in adipose

tissue with reticular fibre

Mesenchymal cells

• Undifferentiated cells• Stellate in shape, • Cytoplasmic process,• Pluripotenant cell• Near blood vessels as

Advential cell

Macrophages (Histiocytes)• Free and Fixed type,• Fixed Cells-• Irregular Shape • filopodia process, • Dark indented eccentric

nucleus, • Derived from monocyte • Involved in phagocytosis• Fused to form giant cell.• Free Cells- rounded, no

filopodia

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 cell

• Round or Fusiform Shaped• Mostly along blood vessels,• Metachromatic granules in

cytoplasm, • Granules have Histamine or

Heparin, • Look like basophil, so called as

connective tissue basophil . • Connective tissue mast cell –

heparin granule, present in skin. • Mucosal mast cell –small,

present in lamina propria of git and respiratory tract

Leucocytes-

. Granulocytes-Neutrophils, Esinophils,

Basophiles. Agranulocytes

Lymphocytes, Monocytes

Leucocytes

Collagen Fibre

• White colour when fresh• Do not branch,wavy• present in bundle• Collagen protein forms

Fibres• Fibres composed of fibril

made of microfibrils• Micro fibrils made up

tropocollagen-striations• Synthesized by fibroblast

Collagen• Tropocollagen is

synthesized by fibroblasts and released into extracellular space where they get polymerized to form collagen fibrils

• Collagen on boiling gives gelatin

• More than 25 types are present

Collagen is also synthesized by

• Chondroblasts: in collagen

• Osteoblasts : in bone

• Smooth Muscle: in blood vessels

• Odontoblasts: in the tooth

Types

• Type1-bones ,tendons, dermis etc

• Type2-cartilage

• Type3-reticular fibres

• Type4-basement membrane

• Type5-blood vessels

Synthesis• Amino acids

• Procollagen

• Three chains

• Tropocollagen

• Collagen

Elastic fibre

• Yellow in color when fresh• Composed of elastin protein• Singly present• Branched and anastomose

forming a network• Can be stretched (one and a

half times)• Synthesized by fibroblast

and smooth muscle cells in blood vessels

• Found in ligamentum flava, ligamentum nuchae, large arteries

Reticular fibre

• Structurally similar to collagen fibres

• Are very thin Immature collagen fibre

• Actively branch to form delicate network therefore named Reticular

• Form supportive framework of lymphoid tissue

• Stained black by silver salts (argyrophillic)

• Composed of Collagen Type III

Ground Substance

• Transparent & Homogeneous• Fills spaces between cells and fibres• Acts as amoleculer sieve facilitating diffusion

between blood and tissues.• Composition:• Mucopolysaccharides• Structural Glycoproteins• Water & Electrolytes

• Mucopolysaccharides(Glycosaminoglycans): Consistency & viscocity of GS, serves as a physical barrier in spreading infection. Examples: Hyaluronic Acid & Heparan Sulphate.

• Structural Glycoproteins: Adhesion of cells to the neighbouring cells. Examples: Fibronectin(Dermis), Chondronectin(in Cartilage) & Laminin(in basement membrane)

• Water & Electrolytes: Maintenance of Fluid balance.

Ground substance

• Polysacchrides - hexurate or galectose

• Carbohydrate protein complex (proteoglycanes)-• 1- mucopolysacchride (glucosaminoglycanes)• NonSulphates-chondroitin and hyluronic

acid • Sulphates - chondotinesulphate, heparitine

sulphate, keratohyline• 2- glycoprotienes- fibronectine(dermis),

chondronectine (cartilage), laminin (b.m)• water & minerals

Classification

Connective tissue1.Ordinary connective tissue- Loose connective tissue -Dense connective tissue Regular Irregular2.connective tissue with special properties Adipose tissue Mucoid tissue Reticular tissue Pigmented tissue3.Scleral connective tissue -Bone -Cartilage4.Lymphoid and heamopoietc connective tissue

Examples• Loose areolar connective tissue-

subperitoneal tissue, endomysium, lamina propria

• Dense collagenous C TRegular- tendon, ligament, aponeurosisIrregular-dermis of skin

• Connective T with special propertiesElastic-Ligamentum nuchaeMucoid/ Embryonic tissue- Wharton’s jellyReticular Tissue- Stroma of lymphoid organ

Loose Connective Tissue

Dense Regular Connective Tissue

Dense Regular Connective Tissue

Dense Irregular Connective Tissue

Dense Irregular Connective Tissue

Dense Irregular Connective Tissue

Dense Irregular Connective Tissue

Irregular Elastic Connective Tissue

Irregular Elastic Connective Tissue

Regular Elastic Connective Tissue

Regular Elastic Connective Tissue

Reticular Connective Tissue

Adipose Connective Tissue

Irregular Adipose Connective Tissue

Mucoid Tissue

MCQ

• Plasma Cells are derived from• 1. Monocytes• 2. Basophils• 3.T lymphocytes• 4. B Lymphocytes

MCQ

• Large number of elastic fibres are present in• 1. Tendon• 2. Ligamentum Nuchae• 3. Basement Membrane• 4. Aponeurosis

MCQ

The fat cells of Multilocular adipose tissue (Brown fat) is characterized by the presence of1.Spherical central nucleus and many lipid droplets. 2.Flat peripheral nucleus and single lipid drop3.Flat central nucleus and single lipid droplet4.Thin rim of cytoplasm

MCQ

• Which of the following is NOT TRUE about Collagen

• 1.Constitutes 30% of the dry body weight• 2.Is synthesized by fibroblasts• 3.Is composed of Mucopolysaccharides• 4.Gives gelatin on denaturation