Connective tissue 1 (1).pdf

Connective Tissue 1 Dr. Fatma Meligy The connective tissue is one of the four basic tissues of the body. (Connective, epithelial, muscular, nervous) Functions: 1.It concerned with connecting the cells of any tissue together and holding the tissues together and in their places. 2.Gives the body its f...

Connective Tissue 1 Dr. Fatma Meligy The connective tissue is one of the four basic tissues of the body. (Connective, epithelial, muscular, nervous) Functions: 1.It concerned with connecting the cells of any tissue together and holding the tissues together and in their places. 2.Gives the body its form. 3.Provides means through which nutrients are transported from capillaries that lie in the intercellular substance to the cells of other tissues. 4.It has a role in defense mechanism and immunity. Structure of connective tissue I- The Extracellular matrix Ground substance Fibers The Connective tissue fibers Collagenic (white) fibers Elastic (yellow) fibers Reticular fibers 1. Collagen (white) fibers Are colorless elongated or wavy bundles which are composed of non- branching small fibrils longitudinal arranged. It is composed of the protein collagen. They are acidophilic thus staining pink with H&E stain E.M appearance Tropocollagen molecules aggregate and become packed together to form fibrils. Collagen fibrils are thin, elongated structures having transverse striations due to alternative dark and light bands. The striations are caused by the regular, overlapping arrangement of the collagen molecule subunits 2. Elastic (yellow)fibers They are long, thin fibers which have They are mainly composed of the protein elastin They branch and may unite and form irregular networks  Function of elastic fibers: They provide elasticity and strength to the tissue. They are stained weak acidophilic by H&E They are well demonstrated with orcein stain where they take a dark brown colour.. With L.M 3. Reticular Fibers: They are Fine fibers arranged in the form of networks They are not visible in H&E preparations but they can be demonstrated well with silver stains where they take a black colour. Function of reticular fibers: They provide a network around the cells of the parenchymal organs and form the framework of the organs. Ground substances of C.T. The ground substance is composed of: 1Mainly hyaluronic acid which is a non – sulphated acid mucopolysaccharidies glucosaminoglycans (GAG). 2Sulphated acid mucopolysaccharids, 3Glycoprotein. It functions in attaching cells to fibers 4- Soluble proteins of the matrix 5Water (tissue fluid): It is the medium through which cells take nutrients and oxygen. Function of ground substance Transport nutrients and oxygen from capillaries to other tissues by diffusion through the tissue fluid in the intercellular substance