Microtechniques Lecture Notes PDF
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Mansoura National University
Dr. Dallia Eita
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Summary
These lecture notes cover various aspects of microtechniques in histology, including tissue collection, fixation, dehydration, clearing, impregnation, embedding, sectioning, using a microtome, different staining methods like H&E, and the differences between paraffin and freezing techniques.
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Introduction DR. DALIA EITA Methods of preparation of light microscopic sections Principles of staining with Hematoxylin & Eosin Types of stains Types of microscopes 1. Demonstrate the methods of tissue fixation and procedures used for tissue embedding. 2. Demons...
Introduction DR. DALIA EITA Methods of preparation of light microscopic sections Principles of staining with Hematoxylin & Eosin Types of stains Types of microscopes 1. Demonstrate the methods of tissue fixation and procedures used for tissue embedding. 2. Demonstrate the common staining methods, their rationale, and the usefulness of cytochemical and histochemical techniques. 3. difference between light and electron microscopes Introduction Histology: Is the science which deals with studying structure of Tissues and cells micro techniques: Methods by which tissue is transformed into hard substance to be cut into thin sections Specimen (Tissue collection ) 2.Fixation Fixatives are chemicals used to preserve the shape and structure of the specimens Example: 10% formalin Effect: 1. Destroy the enzymes that cause autolysis and bacteria that cause putrefaction 2. Harden the tissue 3. Increase affinity of tissue to stain Sectioning Using Microtome Advantages &Disadvantages: a- Paraffin Techinque: -Advantages: easy and rapid - Disadvantages: not suitable for studying fat or enzymes (due to xylol and heat). b- Freezing technique: -Advantage : very rapid suitable for studying fat and enzymes -Disadvantages: difficult to cut Fixation of fresh tissue is essential to: a. Remove water. b. Replace alcohol. c. Prevent putrefaction. d. Clear the sections. e. Keep the cells alive. STAINING Steps of Staining Hydrate in Deparaffinize Stain in H. for 2 descending in xylol min grades of alcohol Wash in Stain in Eosin Blue section in distilled water for ½ min tap water Dehydrate in Mount in Canada ascending grades Clear in Xylol Balsam and put of alcohol coverslip Sections stained with H&E The most commonly used acidic stain is: a. Methylene blue. b. Eosin. c. Toluidine blue. d. Haematoxylin. e. PAS.
