DEVELOPMENT OF CONNECTIVE TISSUE

Mesenchyme Loose Connective Tissue

MesenchymalCells

Fibroblasts

Fibers

Cell Lineage from Mesenchymal Cells

TYPES OF CONNECTIVE TISSUE Loose Connective

Tissue Dense Irregular

Connective TissueDense Regular

Connective Tissue

(e.i. mesentery, omentum) (e.i. dermis of skin) (e.i. tendons, ligaments,cornea)

DENSE IRREGULAR CONNECTIVE TISSUE (DERMIS OF SKIN)

DENSE REGULAR CONNECTIVE TISSUE

Tendon (longitudinal Section) Tendon (tranverse Section)

ELASTIC CONNECTIVE TISSUE IN BLOOD VESSEL WALL

Internalelasticlamina

CONNECTIVE TISSUE FIBERS

Collagenous Fibers (bundles)

Reticular Fibers (networks)

Elastic Fibers(anastomosing bundles)

RETICULAR CONNECTIVE TISSUE

reticular fibers(argyrophilic)

COLLAGEN

FIBERBUNDLE

FiberFibril

Microfibril

Periodic Bands

Tropocollagen

alpha 1 peptidealpha 2 peptide

TEM of Collagen Fibers SEM of Collagen Fibers

SCANNING EM OF COLLAGEN FIBER BUNDLES

procollagen

tropocollagen

ground substance

(mucopolysaccharide)

RER

TEM of Fibroblast and Collagen Bundles

Collagen Types

I - skin, bone, tendon cornea (most common type)II- cartilage, embryonic corneaIII- reticular fibers, loose c.t., blood vessel walls, dermisIV- basal lamina of epithelium

(no fibers, mat of randomly-oriented molecules)

FIBROBLAST

collagen fiberbundles

TEM OF FIBROBLAST WITH COLLAGEN BUNDLES

FIXED CONNECTIVE TISSUE CELL TYPES

Fibroblast(fiber producing cell)

Fibrocyte(mesenchymal- pluropotent)

Adipocytes (fat storage)

Fixed Macrophage(histiocyte)

Adipocytes

fibroblast

Macrophage (light micrograph)

TEM of Macrophage

Fixed Connective Tissue Cells

MONONUCLEAR PHAGOCYTIC SYSTEM

Mononuclearwanderingcell

coalescence

Giant Cell

Macrophages Osteoclasts Kupffer CellsMicroglial

CellsSinusoidalEndothelia

lymph nodes

bone marrow

connective tissue

lung

serous cavities

spleenbone

resorption

liversinusoids

central nervous system

liver spleen marrow

Monocyte

(reticuloendothelial system)

( all characterized by phagocytic activity)

LYMPHOCYTES AND PLASMA CELLS (Agents of the immune response)

differentiation stimulated byimmune activation

Lymphocytes Plasma Cells(produce

immunoglobulins-antibodies)

EOSINOPHILES MAST CELLS

actively phagocyticdestroy immune complexes (antigen-antibody)

Secretion Products:1. Slow-reaction substance of anaphalaxis2. Heparin- anticoagulant3. Histamine- stimulates inflammation4. Serotonin- vasoconstrictor5. Eosinophil Chemotactic Factor

Connective Tissue Cells

Macrophage

Plasma Cell

Lymphocyte

TRANSMISSION EM OF AN EOSINOPHILE

TRANSMISSION EM OF A MAST CELL