Cytology Lecture Notes (1.2) PDF

‫بسم ه الرحمن الرحيم‬ ‫قالوا‏سبحانك‏ا‏ع ‏لنا‏إا‏ما‏‬ ‫ع متنا‏إنك‏أن ‏الع ي ‏الحكي‬ ‫صدق اه العظيم‬ ‫ال قر (‪)32‬‬  Cytology Dr. Samraa Hussein Abdel-Kawi Histology Department Faculty of Medicine Beni-Suef University  ‫رؤ...

‫بسم ه الرحمن الرحيم‬ ‫قالوا‏سبحانك‏ا‏ع ‏لنا‏إا‏ما‏‬ ‫ع متنا‏إنك‏أن ‏الع ي ‏الحكي‬ ‫صدق اه العظيم‬ ‫ال قر (‪)32‬‬  Cytology Dr. Samraa Hussein Abdel-Kawi Histology Department Faculty of Medicine Beni-Suef University  ‫رؤي ‏الجامعه‏‬ ‫ج معه مصريه تسعى إلى الع لميه متميزه فى أدائ ‪ ,‬تحتل‬ ‫قم التع ي الع لى الخ ص بمصر‪ ،‬مصدر الخريجين اأكثر‬ ‫ت ضيا فى أس ا العمل‪,‬تجل مك نه مت دمه فى ق ئم أفضل‬ ‫الج مع الع لميه‪.‬‬ ‫رسال ‏الجامعه‏‏‏‬ ‫المس همه ال ع له فى إعداد الشب ع مي خ ي ليك ن ا‬ ‫ق درين ع ى المن فسه ال ي بد ر قي دى تن يرى فى ن ض‬ ‫المجتمع‪ ،‬ذل بت دي خدم تع يميه بحثيه مجتمعيه فى‬ ‫إط ر ال ي اأخاقي المصريه‬  Vision ‫رؤية الكليه‬ Excellence in performance to accomplish ‫التميز فى اأداء ومواكبغ العصر للريادع فى مجال‬ pioneering in dentistry, in the matters of ‫طظ الفږ واأسناڗ تعليميا وبحثيا ومجتمعيا‬ education, research and society Mission ‫رسالة الكليه‬ Creating qualified graduates educationally, ‫بناء كوادر مؤهلغ علميا وعمليا وملتزمغ أخاقيا‬ practically and ethically, capable of effective ‫قادرع على امنافسغ الفعالغ ومواجهغ التحدياػ‬ competition and able to face national and ‫محليا ودوليا فى مجال طظ الفږ واأسناڗ‬ international challenges, in preventive and ‫الوقائي والعاجي من خال برامج دراسيغ وبحثيغ‬ therapeutic dentistry, through complete up ‫متكاملغ متميزع ومواكبغ للعصر تحفز على اابتكار‬ to date education and research programs ‫واإبداع واستثمار الفرص لتقديږ خدماػ‬ that simulate creativity, innovation and.‫مجتمعيغ عاليغ الجودع‬ opportunity investment to provide the society with high quality services.  Histology Compound of the Greek words: histo "tissue", and logia " branch of learning" Histology is the study of cells and tissues It is commonly performed by examination under a light microscope or electron microscope. Cell: It is the smallest structural and functional unit of all living organisms that can exist independently. They vary in size from 4 to 200 um. So to study cells, one must view them under a microscope. Tissue: Aggregations of cells have the same general characters. There are 4 basic types of tissues: – Epithelial tissue – Connective tissue – Muscular tissue – Nervous tissue Organs: Two or more tissues are combined to give organs, e.g. kidney, liver. Systems: Several organs having interrelated functions collect to form systems, e.g. digestive system and urinary system.  MICROSCOPES Definition: Microscopes are optical instruments for examination of histological specimens. The most important types are light and electron microscope. I- Light Microscope (L.M.) The most common microscope used in routine histological examination. Daylight or electric light is used as the source of illumination. The magnification power (capacity to magnify= 1500 times. II-Electron Microscope (E.M.) Electron beam is used a source of illumination (Instead of light rays). The magnification power: from 1000 to 100,000 times or more. Light microscope Electron microscope How to prepare Tissues for Microscopic Examination (Microtechniques)? Definition: microtechniques are various methods of handling and preparing material for microscopic study. Methods for light microscopy: Paraffin technique (most common). Freezing technique (most rapid). Celloidin technique (most perfect).  Paraffin Technique Steps: 1- Tissue sampling: small pieces of tissue are cut with sharp instrument immediately after death (cadaver) or after operation (biopsy) or from experimental animals. 2- Fixation: Samples are immersed rapidly in a fixative. The most common fixative used in routine work is formol saline. Function of fixatives: – Harden the tissue proteins so some shrinkage may occur. – Prevent putrefaction. – Facilitate cutting and increase affinity to staining. 3- Dehydration: water is removed from the tissue by placing the tissues in ascending grades of alcohol (50%, 70%, 90% then in 100%) to prevent shrinkage of tissue. 4- Clearing: this is done by placing the tissue in xylol or benzol to replace the alcohol. The tissue will appear clear and transparent. 5- Infiltration: tissues are placed in molten soft paraffin wax. so it infiltrates the tissues. 6- Embedding: tissues are placed in molten hard paraffin wax to surround the tissues forming a paraffin block. 7- Sectioning: using microtome. 8- Mounting: sections are put on glass slides. cells are colorless and indistinguishable under light microscope, unless they have been stained  Histological stains for light microscopy: Hematoxylin & Eosin Stain (H & E): The most commonly used in routine histological examinations. Used to identify nucleus and cytoplasm of the cell by two different colors. Hematoxylin (H): is a basic stain, blue in color. It binds to acidic components of the cell. e.g.( nuclei, ribosomes and rough endoplasmic reticulum). The affinity of acidic structures to basic stains is called basophilia. Eosin (E): is an acidic stain, red in color. It binds to basic components of the cell e.g. cytoplasm. The affinity of basic structures to acidic stains is called acidophilia, Nucleus is basophilic So stain by Hematoxylin (Blue)‫‏‬ Cytoplasm is acidophilic So stain by Eosin (Pink)‫‏‬  Silver stain: it stains Golgi apparatus fibers with brown color. Orcein stain: it stains elastic fibers with brown color. Trichrome stains: Three stains are used to give 3 colors to differe t tissue co po e ts. e.g. Masso ’s trichrome. Neutral stain: The best example is the Leishman's stain which is used to demonstrate blood cells. Vital stain: it is staining the living cells inside the living animal. e.g. trypan blue or Indian ink used to stain macrophages. Supravital stain: staining of living cells outside the living body, e.g. staining reticulocytes with Brilliant cresyl blue. Metachromatic stain: it is the stain which gives the tissue a new color different from that of the stain, e.g. Toluidine blue. Histochemical stains: these stains demonstrate chemical components of the cells. e.g. Periodic acid Schiff (PAS): used to stain carbohydrates with deep red color.  The cell Definition: Smallest unit living tissues that can live independently (perform vital functions). Structural and functional unit of all living tissues. Functions: Secretion, Respiration, Absorption, reproduction , Excretion, Sensation, contraction. Size:  varies from 4-150 m  Small cells as lymphocyte 6 m  Large cells as ovum 150 m Shape: Different shapes (Rounded, oval, flat , Stellate, polygonal , Cubical, columnar  Structure of the cell Cytoplasm Nucleus  1- Cytoplasm Matrix Organelles Inclusions Colloidal solution Living structures Non living Proteins Permanent Temporary Carbohydrates Essential in all Not essential Lipids nucleated cells Not in all cells Enzymes Have vital functions Result of cell minerals activity  Cytoplasmic organelles Membranous Non-membranous Cell Ribosomes membrane Microtubules Mitochondria Microfilaments RER & SER Cilia Golgi Flagella Lysosomes  A) Membranous Organelles 1- The Cell membrane Definition A living membrane forming the outermost cover of the cytoplasm LM: H & E: Can not be seen because very thin (8-10 nm) Special stain: Silver or PAS EM: Two dark lines separated by a light one = Trilamellar membrane = Unit membrane  Functions of Cell Membrane: 1- Encloses the cell, maintains its shape and Keep its internal composition 2- Controls transport of materials between cell and surroundings a- Simple (passive )transport: molecules cross according to concentration gradient e.g. water and gasses b- Active transport: Molecules pass against concentration gradient so needs energy e.g. Na+/K pump c- Bulk transport: of large substances Endocytosis: by which substances enter the cell i- Phagocytosis = if the substance is solid ii- Pinocytosis= if the substance is fluid 1 2 3 4 5 6 b) Exocytosis: in which substances leave the cell to outside. e.g. Extrusion of residual bodies 1 2 3 4 5 6  D- Selective transport: by presence of receptors in the cell membrane which allow certain substances only to enter the cell so called (Receptor mediated endocytosis) 4- Functions of Receptors Cell recognition (cell identity) , protection and immunity 5- Cell membrane modifications : Microvilli: Increase surface area for absorption or secretion Cilia: move particles above the cell membrane in one direction Flagella: form the tails of spermatozoamuscles. 6- Conduction of excitation waves in nerve cells and  2- Mitochondria (Mito = thread, chondria = granules) Definition: membranous organelles, containing enzymes responsible for cell respiration and energy production. They are considered the power-house or the battery of the cell. Sites: accumulate in the cytoplasm at sites of most activity. Number: More numerous in highly active cells.. Mitochondria can divide as they have their own DNA and RNA. LM: Not seen by H & E Special stains: Iron hematoxylin & Janus green stain EM: 2 membranes + 2 Spaces outer Thicker, Smooth membrane inner Thinner, and projects into the membrane cavity forming cristae EM 2 spaces A. Inter-membranous space Between the two membranes B. Interior space Filled with matrix Full of granular materials: 1. Elementary particles: They contain respiratory enzymes 2. Matrix granules (lipids, proteins, Ca++, Mg++), 3. DNA & RNA It was recently discovered that all mitochondria are derived from those in the fertilized ovum and are entirely of maternal origin. Mitochondria  3- Endoplasmic Reticulum Network of communicated tubules (cisternae)‫‏‏‬ that form reticulum inside the cytoplasm Types:  A. Rough Endoplasmic Reticulum (rER)‫‏‬ Definition: parallel flattened and interconnected membranous tubules called cisternae, studded with electron- dense particles, the ribosomes. Site: Well developed in protein synthesizing cells (fibroblasts) LM: H & E: Can not b seen If increased give cytoplasmic basophilia  EM parallel flattened and interconnected membranous tubules called cisternae, studded with electron-dense particles, the ribosomes. Ribosomes bounded to specific receptors (ribophorins). Under the receptor is a pore Functions: Dealing with protein synthesis that will be secreted by the cell Acts as an intracellular pathway  B) Smooth Endoplasmic Reticulum (sER): It is concerned with lipid synthesis. Sites: well-developed in fat & steroid hormones forming cells, e.g. liver cells & endocrine cells. LM: H&E: can not be demonstrated, But if abundant: cytoplasmic acidophilia EM: : anastomosing tubules in an irregular way not in parallel array like rER with smooth membranes (no ribosomes). Function of smooth endoplasmic reticulum Lipid synthesis and storage. Cholesterol & steroid hormones synthesis. Glycogen storage & breakdown as in liver and muscle cells. Drug detoxification in liver cells. Calcium storage in muscle fibers. HCl formation in stomach. Acts as an intracellular pathway.