Human Histology PDF

Human Histology examination of the tissue under a microscope to  Defined as the study of microscopic structures of diagnose various skin conditions, including biological materials derived from humans and the cancers and precancerous lesions...

Human Histology examination of the tissue under a microscope to  Defined as the study of microscopic structures of diagnose various skin conditions, including biological materials derived from humans and the cancers and precancerous lesions means by which their individual components are  This biopsy method is commonly used to assess structurally and functionally related. skin lesions, rashes, or tumors. It can help  Intertwines with the disciplines of biology, diagnose skin cancers such as melanoma and biochemistry, physiology, and pathology. non-melanoma types, as well as other skin disorders like psoriasis or eczema. The sample Histopathology obtained provides valuable information for Deals with the preparation of small samples of tissues for treatment planning microscopic examination.  Punch biopsies are quick to perform, typically  Scalpels under local anesthesia, and result in minimal  Needles scarring. They are particularly effective because  Special flexible cannulae they provide a full-thickness sample of the skin, which is crucial for accurate diagnosis Examination may be done on: 5. Shave Biopsy Fresh Tissues  Can use blade or scalpel  When there is an immediate need for evaluation  Cutting off infective tissue  Sample is obtained in the middle of surgery  Warts, lissions, skin myeloma  Methods: 6. Bone Marrow Biopsy - Teasing (separating)  Utilizes big needle - Crushing (squashing)  Leukemia, lymphoma - Smearing  Laparoscopy - Frozen section Preserved Tissues Preserved Tissues  A better and more effective means of studying  Routinely done in the histopathology section tissues whether normal or abnormal is by examination of their sections and smears which Common Types of Biopsies have been permanently preserved, stained for 1. Surgical Biopsy demonstration of specific structures and mounted  Excisional – Whole lump on glass slides with cover slips for permanent  Incisional – Just a small portion keeping. The difference of the two types of surgical biopsy is the  Better and more effective means of studying amount of the sample that is obtained tissues  Consists of 11 steps (FDD-CIET-SSML) 2. Needle Biopsy  Fine needle FDD-CIET-SSML - Collects sample of cells  Steps in processing preserved tissues - Less invasive  Underlined ones are optional - Thinner needle F – Fixation - It aspirates  Process by which constituents of the cells and  Core needle tissues are fixed so that they can withstand - Collects core of tissue subsequent treatment with various reagents with - Ultrasound or MRI guides process minimum loss or distortion. - Larger needle 3. Endoscopic Biopsy  First and most critical step in histopathology  An endoscopic biopsy is a medical procedure  Preservation – other term where tissue samples are collected using an  10% neutral buffered formalin/formative endoscope, a flexible tube equipped with a light - Usually used and camera. This technique allows doctors to - Amount should be 20x of the sample visualize internal organs and collect samples for  Primary goal diagnosing conditions such as cancer, infections, - Preserve morphology, and chemical integrity or inflammation of the tissue as life-like manner as possible  During the procedure, the endoscope is inserted  Secondary goal through natural openings (like the mouth or - To harden and protect the tissue from damage rectum) or small incisions. Specialized  Common fixative solutions instruments can then be passed through the - Alcohols endoscope to obtain small tissue samples, which - Aldehydes (formalin) are sent to a laboratory for analysis D - Decalcification (optional)  Endoscopic biopsies are crucial for identifying  Teeth, bones, and samples that involves calcium abnormalities in various organs, guiding treatment  Amount used should be 20x of the sample decisions, and monitoring disease progression, especially in cases of suspected malignancies D – Dehydration 4. Punch Biopsy  Process of removing intracellular and extracellular  A punch biopsy is a medical procedure that water from tissue following fixation and prior to involves removing a small, cylindrical piece of wax impregnation skin, including all its layers (epidermis, dermis,  Volume is 10x the amount of the tissue and subcutaneous tissue), using a circular cutting  The best way to dehydrate a sample is to do it by tool. This technique allows for a comprehensive batches  Ascending order/amount of alcohol  Microtome machine is used - 70 – 75%  Ribbons - 80 – 85% - Tissues that are cut - 90 – 100%  Size of samples should be 4-6 micrometers - I’m not sure sa numbers but it is ascending  These ribbons are very fragile order until makalab-ot sa 100  After cutting put it into the filtration box. The  Wax is not soluble in water, so it is important to interior should be black. The temp. of the filtration dehydrate properly box should be 45-50 degree C C – Clearing  Fishing technique is used with glass slides  Process where the tissue is made translucent by S – Staining replacing the alcohol or dehydrating agent with a  Process that enables one to see and study the substance that makes the tissue more transparent architectural pattern of the tissue and physical and ready for embedding in paraffin or other characteristics and structural relations of tissues embedding media. and their cells  Dealcoholization – other name  Dyeing takes place  Ethanol – best reagent  Exposed to different reagents  Methanol – toxic reagent  Commonly used stains  Common clearing agents - Hematoxylin - Xylene/xylol - Eosin - Tolene - Benzene 3 Major Classifications - Chloroform 1. Histological – tissues are demonstrated by the - Cedarwood oil staining 2. Histochemical – the tissue can be studied by the I – Impregnation chemical reaction of the stain  Process whereby the clearing agent is completely 3. Immunohistochemical – antibodies are involved removed from the tissue and replaced by a medium that will fill all natural spaces and H and E Staining interstices of the tissues, that will set to a  Cell substances with a net negative (anionic) sufficiently hard consistency to allow cutting of charge, such as DNA and RNA, react strongly with thin sections without distortion hematoxylin and basic stains; such material is  Infiltration – other name said to be “basophilic.”  Clearing agent is completely removed  Cationic substances, such as collagen and many cytoplasmic proteins react with eosin and other  If dehydration is not doe properly, the wax will not acidic stains and are said to be “acidophilic.” completely fit the spaces 3 Types of Impregnation M – Mounting 1. Paraffin wax impregnation  Mounting medium - Simplest, most common and best embedding - A syrupy fluid applied between the section and medium used for routine tissue processing the coverslip after staining, setting the section - Melting point of the wax is 54-58 (while sa firmly, preventing movement of the coverslip book 56-58)  Coverslip first then mounting medium - The required temperature of the paraffin oven  Mountant – other name for mounting medium is set to 2-5 degree C above the melting point  Permanent mountants of the paraffin - Eukit – commonly used and readily available 2. Collodion/Celloidin impregnation - Canada Balsam - Purified form of nitrocellulose soluble in many  Temporary Mountants solvents, suitable for specimens with large - Water hollows cavities which tends to collapse, for - Glycerin hard and dense tissue (teeth and bones). 3. Gelatin impregnation - Rarely used - Used for delicate specimens and frozen tissue sections because it prevents fragmentation E – Embedding  Process by which the impregnated tissue us placed into a precisely arranged position in a mold containing a medium, which is then allowed to solidify. T – Trimming (optional)  Cleaning the mold if it is not perfect S – Sectioning  Process whereby alcohol or dehydrating agent is removed from the tissue and replaced by a fluid that will dissolve the wax with which the following tissue must be impregnated  Where the sample is cut into pieces