Types of Tissue PDF

 I. Epithelium 1. Covering epithelium 2. Glandular epithelium 3. Neuroepithelium 4. Myoepithelium 1. Covering epithelium  Shape of Cell Layer Types and sites Simple Thin cells with bulging 1. Lining of blood vessels. squamous nuclei....

 I. Epithelium 1. Covering epithelium 2. Glandular epithelium 3. Neuroepithelium 4. Myoepithelium 1. Covering epithelium  Shape of Cell Layer Types and sites Simple Thin cells with bulging 1. Lining of blood vessels. squamous nuclei. 2. Lung alveoli 3.Outer layer of bowman’s capsule Simple cuboidal Cubical-shaped cells 1. Renal tubule with central and round 2.Thyroid gland nuclei Simple Column-like cells with 1. Secretory: in the stomach. columnar basal and oval nuclei. 2. Absorptive: in the intestine. 3.Ciliated: uterus & fallopian tube - Overcrowded 1. Ciliated: trachea and bronchi. Columnar cells, all reach 2.Non-ciliated: large ducts of glands the basal lamina, but Pseudostratified not all cells reach the surface. 2. Nuclei are at various levels 2. Glandular epithelium 3. Neuroepithelium  Connective tissue  Connective tissues supports and physically connects other tissues and cells together in the organs. Development: The connective tissue originates from embryonic mesoderm. The interstitial fluid of connective tissue acts as a medium for diffusion of nutrients and waste products. General structure The term Connective Tissue is applied to all tissues formed of: A. Connective tissue cells B. Extracellular matrix (ECM) 1. Connective tissue fibres. 2. Ground substance.  Connective tissue cells A. Fixed (resident) B. Free (Wandering) Connective tissue cells Connective tissue cells 1. Mesenchymalcells. 1. Mast cells. 2. Fibroblasts. 2. Plasmacells. 3. Adipocytes. 3. Leucocytes(WBCs). 4. Macrophages.  Fixed cells 1. Mesenchymal cells Un-differentiated cells give other CT cells or remain as reserve cells. Function: the mother cells in embryos. Fibroblast The most common cell in the connective tissue proper.  Origin: from mesenchymal cell.  Shape: oval cell with long processes.  Nucleus: oval, pale and euchromatic.  Cytoplasm: rich in rough endoplasmic reticulum (RER) , mitochondria and well-developed Golgi App. Functions Synthesize & maintain most components of extracellular matrix (ECM) eg. Collagen & elastin.  Adipocytes Unilocular adipocyte (white)  Adipocyte Origin: from the mesenchymal cells.  : Shape: large, Spherical & contains a single l arge lipid droplets. In preparation, the fat dissolves leaving a single large vacuole→ signet- ring shape. (H&E). Fattened and eccentric nucleus: Functions Long-term energy storage. Multilocular adipocyte (brown)  Origin: from the mesenchymal cells.  Shape: smaller cells, polyhedral & contains multiple small lipid droplet and numerous mitochondria. In preparation, the fat dissolves leaving multiple small vacuoles. In H& stain. Round and central nucleus. Functions  Heat production  Macrophages (Histiocytes)  Origin: from blood monocytes.  Shape: large with many processes.  Nucleus: large, kidney-shaped.  Cytoplasm: rich in lysosomes Functions  Macrophages have well-developed phagocytic ability.  Phagocytose foreign particles and tissue debris (damaged cells & fibres).  FREE cells: 1- Mastcell  Origin: from Mesenchymal the bone marrow.  Site: - Around small blood vessels of skin and mesentery. - In the connective tissue of the digestive and respiratory systems.  Shape: large & oval with large Nucleus: large  Cytoplasm: full of large granules (covered the nucleus).  Special stain: metachromatic staining (the granules contain GAGsthat change the colour of blue basic dyes eg toluidine blue → red or purple). Functions Synthesis and secretion of: Synthesis and secretion of: - Histamine: Allergic reaction-inflammation Heparin: anticoagulant  FREE cells: 2 Plasmacell Origin: from activated B-lymphocytes.  Shape: large & oval. Nucleus: large with special arrangement of chromatin: (clock-faceappearance). Cytoplasm: basophilic ; rich in rough endoplasmic reticulum & well- developed Golgi apparatus. Functions Synthesis and secretion of: It is responsible for the production of circulating antibodies (immunoglobulins) against antigens  Extracellularmatrix (ECM) A. Connective tissue fibres B. Ground substance 1. Collagen fibres 2. Reticular fibres 3. Elastic fibres Types of fibers Collagen Reticular Elastic Subtypes and Sites 28 types. The supporting tissue of in organs that need more parenchymatus organs eg liver, flexibility: Type I collagen endocrine glands and lymphoid The most abundant and widely Wall of blood vessels especially organs. distributed. arteries. Forms fibres which aggregate in the form of large bundles Bronchial tree. eg in the tendon, dermis of skin and capsule of organs. Type II collagen: Site: in the cartilage. Forms fibrils only, no fibres or bundles. Type I II collagen: bound to carbohydrate chains to form reticular fibres. Characteristics Strong. Very thin fibres Similar to rubber (elastic) Properties: bound to carbohydrate chains. Thinner than type I collagen. Resistant to normal shearing and Form a network In the form of fibres or lamellae. tearing forces. (reticulum) around cells. Stains: H&E: Acidophilic H&E. : not visible H&E: pale pink. Silver: black Synthesized by: fibroblast. Fibroblasrt Fibroblast Smooth Muscles cells of Bl vessels  Groundsubstance Characters & functions  Amorphous transparent gel-like material.  Fills the space between cells and fibres.  Binds cells and fibres.  Acts as a medium for transport of metabolites.  Acts as a barrier against microorganisms. Structure 1. Much water content. 2. GAGS(glycosaminoglycans): Long polysaccharide molecules. 3. Proteoglycans Acore of protein to which attached GAGS. 4. Multiadhesive glycoproteins: large protein Proteoglycans Glycoprotein molecule + small carbohydrate molecule.  Types of Connective Tissue A. Connective tissue proper B. Embryonic Connective T. 1. Loose (areolar) C.T. 1. Mesenchymal C.T. 2. Mucoid C.T. 2. Dense C.T. A. Dense irregular C.T. C. Specialized connective T. B. Dense regular C.T. 1. Cartilage. 1. Collagenous. 2. Elastic. 2. Bone. 3. Reticular C.T. 3. Blood. 4. Adipose C.T. CT types Mucoid Mesench Loose Areolar. Reticular C.T. White adipose Brown adipose C.T ymal C.T. C.T. Chracacter Jelly-like type of connective Both Loose: flexible. Form a network Fat storage. heat s tissue mesench (reticulum) production. ymal Areolar: shows areolae around cells. and (cavities) on staining mucous Abundant ground substance. connecti Cells, fibres and matrix Structure ve in nearly equal parts Sparse collagen fibres. tissues A network of Incomplete Lobules of are The most common cell: Scattered fibroblasts. reticular cells and lobules of multilocular restricte fibroblast. fibres. unilocular adipocytes. d to the adipocytes. The most common fibre: embryo. It is brown in color collagen. Colour: white to due Moderate amount of yellow. to its high ground substance vascularity and presence of numerous mitochondria. An embryonic type of it forms the The most common Site connective tissue. stroma of organs typeof adipose (endocrine tissue` Wharton´ jelly of the The most common type. glands, lymph (almost all) umbilical cord (principal nodes, liver, and component of umbilical Fills spaces between spleen). .Newborn:. cord). muscles and nerve fibres. Located mainly in the Pulp cavities of young In the serous membranes back, (growing) teeth (which eg peritoneum. shoulders & remain as a postnatal neck. source of mesenchymal stem cells) Adults: Greatly  Dense Connective Tissue Dense Irregular collagenous C.T. Dense Regular Collagenous C.T. Dense Regular Elastic C.T. Properties Resistant to stress from all directions The orientation of the collagen fibers The orientation of the elastic fibers in one directions in one directions Resistant to stress from all directions. Resistant to prolonged or repeated Resistant to stresses exerted in one stresses exerted in one direction direction Structure 1. Mainly irregular bundles of collagen 1. Parallel bundles of collagen type 1. Parallel elastic fibres. fibers type I I. 2. Few Fibroblasts between 2. Few cells and fibroblast is the main 2. Regular Fibroblasts between the the fibres. type. bundles 3. Little ground substance 3. Little ground substance. 3. Little ground substance. Site Dermis of the skin Tendon Large arteries e.g. aorta Cornea of the eye. Ligamentum flavum. Suspensory ligament of penis. Resources 1. Junqueira LC,Carneiro J:Basic Histology. Text and Atlas, 11th edition (2005), LANGEMc Graw Hill, Chapter: 8, PP: 160-211. 2. Young B, Heath JW: WHEATER´sFunctional Histology. AText and Colour Atlas (2001). Churchill Livingstone. Chapter 9, PP: 101-143.