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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.
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Histology • Instructors:FarisMohammednoorAltaf 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 4th Ed. (April 1, 2005)
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
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).
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.
The Cell • The Cytoplasm • Nucleus
The Cytoskeleton • Microtubules • Intermediate Filaments • Actin Filaments