CONNECTIVE TISSUE CONNECTIVE TISSUE Connective tissue is one

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 • Packing • Storage Structural & Mechanical Fills spaces, Shape to the organ Adipose tissue: energy Loose areolar CT: water & Electrolytes • Transport • Repair • Defense Medium for Nutrients & Metabolic wastes Fibroblasts: matrix and fibres 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 is also synthesized by • Chondroblasts: in collagen • Osteoblasts : in bone • Collagen on boiling gives gelatin • Smooth Muscle: in blood vessels • More than 25 types are present • Odontoblasts: in the tooth

Types • Type 1 -bones , tendons, dermis etc • Type 2 -cartilage • Type 3 -reticular fibres • Type 4 -basement membrane • Type 5 -blood vessels

Synthesis • Amino acids • Procollagen • Three chains • Tropocollagen • Collagen

Elastic fibre • Yellow in color when fresh • Composed of elastin protein • Singly present • Branched 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) • Non. Sulphates-chondroitin and hyluronic acid • Sulphates - chondotinesulphate, heparitine sulphate, keratohyline • 2 - glycoprotienes- fibronectine(dermis), chondronectine (cartilage), laminin (b. m) • water & minerals

Classification Connective tissue 1. Ordinary connective tissue- Loose connective tissue -Dense connective tissue Regular Irregular 2. connective tissue with special properties Adipose tissue Mucoid tissue Reticular tissue Pigmented tissue 3. Scleral connective tissue -Bone -Cartilage 4. Lymphoid and heamopoietc connective tissue

Examples • Loose areolar connective tissuesubperitoneal tissue, endomysium, lamina propria • Dense collagenous C T Regular- tendon, ligament, aponeurosis Irregular-dermis of skin • Connective T with special properties Elastic-Ligamentum nuchae Mucoid/ Embryonic tissue- Wharton’s jelly Reticular 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 of 1. Spherical central nucleus and many lipid droplets. 2. Flat peripheral nucleus and single lipid drop 3. Flat central nucleus and single lipid droplet 4. 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