Histology 1/ PA 5 Connective Tissue I 2024 PDF

PAGE 1 HISTOLOGY 1/ PA https://www.umfst.ro https://edu.umch.de 5/Connective tissue I 2024 7 - 8 of October PRESENTERS: Lecturer Dr. Laura CHINEZU...

PAGE 1 HISTOLOGY 1/ PA https://www.umfst.ro https://edu.umch.de 5/Connective tissue I 2024 7 - 8 of October PRESENTERS: Lecturer Dr. Laura CHINEZU Assist. Prof. Drd. Alex SĂLĂGEAN  PAGE 2 Connective tissue (I) 1. Cells of the connective tissue, HE stain, granulation tissue. 2. Collagen fibers, van Gieson’s stain, mammary gland. 3. Reticulin fibers, silver impregnation, spleen  Connective tissue PAGE 3 - is one of the best represented tissues in the body; - it is formed of three main elements, which are present in different proportions: cells, fibers and ground substance; - fibers together with the ground substance form the extracellular matrix (ECM). – The cells - the first elements that develop - will elaborate the other two components, the fibers and the ground substance. Fixed (resident) cells: fibroblast/fibrocyte, chondroblast/chondrocyte, osteoblast/osteocyte, adipocyte, cells that are always present in the different types of connective tissue; Free cells (cells migrated from the blood): macrophage, plasma cell, lymphocyte, granulocyte, cells that are not constantly present in the connective tissues.  1. Cells of the connective tissue, HE stain, PAGE 4 granulation tissue – The granulation tissue is a repair tissue, which contains newly developed collagen fibers and all types of cells of the connective tissue, both fixed cells and cells migrated from the blood. On low magnification: - numerous cells can be observed, all types of cells of the connective tissue, both fixed cells and cells migrated from the blood - along with collagen fibers (isolated or arranged in relatively disordered bundles) - - and numerous blood vessels, as the abundant vascularization is characteristic for this type of tissue.  PAGE 5 Granulation tissue, numerous cells can be observed, along with collagen fibers  1. Cells of the connective tissue, HE stain, PAGE 6 granulation tissue On high magnification: - the following cell types can be recognized: The fibroblast – medium sized, ribbon-shaped, elongated cell, – with pale basophilic cytoplasm, – which can be recognized by the large, oval, hypochromatic and centrally located nucleus, with visible nucleoli. Fibroblasts, recognized by the large, oval, PAGE 7 hypochromatic and centrally located nucleus, with visible nucleoli.  PAGE 8 The fibrocyte – characterized by the elongated, intensely hyperchromatic and centrally placed nucleus; – the cell is also elongated, spindle-shaped, with a low quantity of hardly visible eosinophilic cytoplasm.  PAGE 9 Fibrocytes, characterized by the elongated, intensely hyperchromatic and  PAGE 10 The adipocyte (adipose cell) - a large, round or polygonal cell, - with a single lipid-storage droplet (that does not stain with HE – the lipids are extracted during tissue processing) that pushes the cytoplasm and nucleus to the periphery - and a flattened, hyperchromatic nucleus. - all these features will create the “signet ring cell” appearance in HE staining. Adipocytes, large, PAGE 11 round or polygonal cells, with a single lipid-storage droplet (that does not stain with HE)  PAGE 12 Plasma cell - round or oval cell, with a dark, basophilic cytoplasm - the appearance of the nucleus is characteristic for this cell: - rounded, eccentric; - a particular distribution of the chromatin - the intensely stained granules of heterochromatin and the pale granules of euchromatin have an alternative arrangement, in radial fields, showing a cartwheel configuration.  PAGE 13 Plasma cells, with a rounded, ecccentri c nucleus.  PAGE 14 Macrophage - cell with variable size according to the quantity of the phagocytosed material; - has an irregular shape and a pale eosinophilic cytoplasm that contains the phagocytosed material (vacuolar appearance of the cytoplasm); - sometimes macrophages are able to merge, forming multinucleated giant cells: large cells, with abundant cytoplasm and several nuclei.  PAGE 15 Macrophages, with different shapes and vacuolar  PAGE 16 Multinucleated giant cell, large cell, with abundant cytoplasm and several nuclei.  PAGE 17 Limphocyte - small cell, - with a round, hyperchromatic nucleus, - and a small amount of basophilic cytoplasm appearing as a thin crescent-shaped rim at the periphery.  PAGE 18 Limphocytes , small cells, with a round, hyperchromatic nucleus. 2. Collagen fibers, van Gieson’s stain (acid fuchsin), mammary gland. PAGE 19 – The connective tissue has three types of fibers: Collagen Reticular (type III collagen) Elastic – Excepting the collagen fibers, which stain in light pink, the other ones are not visible in HE. – Van Gieson’s stain is used for visualizing and differentiating collagen fibers from other structures: with this stain collagen fibers are colored in bright red and the epithelial tissue and the nuclei in brown-black.  On low magnification: PAGE 20 - we can see the collagen fibers stained in bright red, with a regular or an irregular arrangement;  PAGE 21 On high magnification: – we can observe the collagen fibers as more or less wavy, sinuous lines; – they can be either isolated or grouped in fine or rough bundles; – although the collagen fibers of a bundle can detach and join the ones in the neighboring bundle, they never branch or merge (anastomose) with other fibers; – among collagen fibers, we can see the brown-black nuclei of the fibrocytes: oval, flattened and intensely colored (hyperchromatic); – the fibrocytes are often tightly bonded to the collagen fibers that they synthesize: the cytoplasm (scanty) and the cellular boundaries cannot be observed; fibrocytes will be recognized and represented only by their nuclei. The brown- black nuclei PAGE 22 of the fibrocytes: oval, flattened and hyperchroma tic. Collagen fibers, isolated or grouped in fine or rough 3. Reticulin fibers, silver nitrate impregnation, PAGE 23 spleen. - the reticulin fibers are argyrophilic and they can be visualized by silver impregnation, which colors them in black; On low magnification: - a network of reticular fibers stained in black can be seen.  PAGE 24 Reticulin fibers from the kidney, stained in black, forming a network. Reticulin fibers from the PAGE 25 spleen, stained in black, thin, richly branched, they anastomose with other fibers forming networks.  PAGE 26 On high magnification: - we can observe the reticular fibers as irregular lines; - they are thinner than collagen fibers; - they branch and anastomose with other fibers forming networks with gaps of different shapes and sizes; - they do not group in bundles. Reticulin fibers from PAGE 27 the kidney branch and anastomose with other fibers forming networks with gaps of different shapes and sizes. Reticulin fibers from the PAGE 28 spleen, thin, richly branched, they anastomose with other fibers forming networks.  PAGE 29 Requiered for Histology Informations: PAs