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Histology Instructors: Faris Mohammednoor Altaf MT. MS. Ph.D. د. فارس محمد نور سعيد ألطف Email: pharmacology.toxicology@gmail.com Phone# 5720000 ext. 4179 Mohammad Afzal Khan M.B.B.S., M.Phil. Email: afzalmakkah@hotmail.com Phone# 5270000 ext. 4149 Text/Atlas: - Basic Histology Text and Atlas, Luiz Carlos Junqueira and Jose Carneiro, 11th Ed., McGraw-Hill Publishing, 2005. - Color Atlas of Histology (Paperback) by Leslie P Gartner, James L Hiatt 4 th Ed. (April 1, 2005)
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Introduction The name "Histology" is derived from the Greek word for a tissue "Histos", and "-logos" = the study of. Four fundamental tissues are recognized: epithelial tissue, connective tissue, muscular tissue, and nervous tissue. Tissues are made of cells and extracellular matrix. Intense interaction between cells and matrix cells and extracellular matrix form a continuum that functions together and reacts to stimuli and inhibitors together The small size of cells and matrix components makes histology dependent on the use of microscopes
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BASIC TECHNIQUES Preparation of histological sections 1. Fixation 2. Embedding 3. Microtomy 4. Staining 5. Permanent Mounting Frozen sections Total preparations In some cases the tissue to be examined is a very thin membrane. Cell Smears blood or bone marrow, epithelial cells (e.g. from the oral cavity, cervix uteri).
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STAINING TECHNIQUES 1. Hematoxylin and Eosin (H&E) – The Hematoxylin is a basic dye that stains acidic components of cells a blue color (basophilia). Hematoxylin stains the nuclei of cells, and the RER of the cytoplasm – Eosin is an acidic dye that stains the basic components of the cells a reddish-pink color (acidophilia). Most of the cytoplasm of cells is stained by eosin. Bone matrix is also stained by eosin. 2. Periodic acid-Schiff (PAS) staining – mucus, the basal lamina, glycogen. 3. Orcein – elastic fibers a dark brown-purple color. 4. Osmium tetroxide – Osmium is used to stain lipids a dark black color. myelin of myelinated nerves, or lipid droplets in the liver or steroid-secreting cells. 5. Oil Red O – Oil Red O is used to stain lipids a red-orange color in unfixed frozen sections. 6. Toluidine blue – so-called metachromatic stain. It is a blue stain that stains specific components of tissues a purple color. This change in staining color is known as metachromasia. Metachromasia is seen in the matrix of hyaline cartilage, or in the granules of mast cells. 7. Impregnation – Silver impregnation techniques are also widely used to demonstrate reticular fibers.
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Light Microscopy
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Phase-Contrast Microscopy
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Polarizing Microscopy
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Fluorescence Microscopy
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Electron Microscopy
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The Cell The Cytoplasm Nucleus
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Plasma Membrane
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Function of PM
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Mitochondria
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Ribosomes
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Endoplasmic Reticulum
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Golgi Complex
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Lysosomes
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The Cytoskeleton Microtubules Intermediate Filaments Actin Filaments
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The Cell Nucleus
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