BSMT Human Histology Lecture PDF

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TOPIC: M1 - INTRODUCTION TO HUMAN HISTOLOGY

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Human Histology

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Histology Technicians ○ In USA only ○ Studies tissues (biopsy) Pathologist ○ In Philippines ○ Deals with abnormalities of tissue causing diseases ○ RMTs assists the Pathologists ○ They are usually the head of the Laboratory

-logy/ ‘logos’ - Study of Histology → “histos” + “logos” → Study of microanatomy of cells and tissues/ formation - structure - function ○ “Histos” - Tissue ○ Focuses on tissue Pathology → “pathos” + “logos” → study and diagnosis of diseases through microscopic examination of surgically removed organs, tissues, and other body fluids ○ “Pathos” - disease or suffering ○ Focuses on the diagnosis of a diseases in where you can detect the problem in the removed tissue organ or other body fluid ○ Finding the cause of the abnormal characteristic of tissues, organs and other body fluid Pathophysiology → “pathos” + “physio” + “logos” → Systematic study of functional changes in cells, tissue, organs altered by a disease &/or injury ○ “Pathos” - disease or suffering ○ “Physio” - normal physiologic process of human ○ studies the mechanism of how the disease is developed from that normal physiologic process ○ Not for diagnosis procedure unlike pathology, what you check is the mechanism involved where in from that normal tissue it became abnormal, what happened to the tissue? Why did it become non functional? ○ Normal processes of cells, tissue organs altered by a disease. ○ ABOUT MECHANICS, Histopathology → “histos” + “pathos” + “logos” → Study of changes in tissues caused by a disease ○ “Histos” - tissue ○ “Pathos” - disease or suffering ○ Changes in the tissues specifically

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DIAGNOSIS of tissues which are altered by disease which can be seen by microscope ○ Diagnostic procedure is involved. ○ Also one of the section of laboratory Cytology → “cyto/kytos” + “logos” → study of cell/ formation - structure - function ○ “cyto/kytos” - cells ○ Specific study of cell Organization of the Body ○ Cells → Tissues → Organs → Organ System

Robert Hooke (17th Century)

Discovered Cells

Marcello Malpighi (17th Century)

“Father of Histology”

Robert Brown (17th Century)

Introduce the “Nucleus”

Henle

Published the 1st Human Histology

Matthias Schleiden

Cell Theory

Theodore Schwann

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Bright Field Microscope ○ most common type that is used ○ Usually in Routine Laboratory ○ stained tissues are examined with ordinary light; has optical system: ■ Condenser – collects & focuses cone of light to object to be studied ■ Objective – interchangeable lens that project image of object. Near the specimen ■ Eyepiece – “oculars” that give extra magnification and project image onto viewer’s retina. Near the eyes ○ NOTE: magnifying power of objective x magnifying power of eyepiece = TOTAL MAGNIFICATION Dark - Field Microscope ○ Usually for the detection of a specific bacteria called Treponema Pallidum, it is the causative agent of syphilis ○ illuminate unstained samples causing them to appear lit against dark background ○ contains special condenser that scatter light so it would reflect off the specimen at an angle

Phase - Contrast Microscope

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Used to view living cells because of its high refractive index. ○ enhance contrast for transparent and colorless specimens Electron Microscope ○ Very minute cells or microorganism ○ Usually seen in Reference Laboratory ○ TEM = Transmission Electron Microscope ■ allows resolution of subcellular structures in very thin tissue sections ○ SEM = Scanning Electron Microscope ■ allows resolution of 3D views of surface of tissues, cells, & subcellular structures

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STRUCTURAL PARTS OF THE MICROSCOPE ○ Head - This is also known as the body, it carries the optical parts in the upper part of the microscope. ○ Base - It acts as microscopes support. It also carries the microscopic illuminators. ○ Arms - This is the part connecting the base and to the head and the eyepiece tube to the base of the microscope. It gives support to the head of the microscope and it is also used when carrying the microscope. Some high-quality microscopes have an articulated arm with more than one joint allowing more movement of the microscopic head for better viewing. OPTICAL PARTS OF THE MICROSCOPE ○ Eyepiece - lens that is near the eyes. also known as the ocular. This is the part used to look through the microscope. It's found at the top of the microscope. Its standard magnification is 10x with an optional eyepiece having magnifications from 5x – 30x. ○ Eyepiece Tubes - it's the eyepiece holder. It carries the eyepiece just above the objective lens. In some microscopes such as the binoculars, the eyepiece tube is flexible and can be rotated for maximum visualization, for variance in distance. For monocular microscopes, they are none flexible. ○ Objective Lenses - Near the specimen or slide. These are the major lenses used for specimen visualization. They have a magnification power of 40x-100x. There are about 1- 4 objective lenses placed on one microscope, in that some are rare facing and others face forward. Each lens has its own magnification power. ■ Scanner - Uses Coarse Adjustment Knob ■ LPO - Uses Coarse Adjustment Knob ■ HPO - Uses Fine Adjustment Knob ■ OIO - Uses Fine Adjustment Knob ○ Revolving Nose Piece – also known as the revolving turret. It holds the objective lenses. It is movable hence it can revolve the objective lenses depending on the magnification power of the lens.

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Adjustment Knobs – These are knobs that are used to focus the microscope. There are two types of adjustment knobs: ■ Fine Adjustment Knob ■ Coarse Adjustment Knob Stage - This is the section on which the specimen is placed for viewing. They have stage clips holding the specimen slides in place. The most common stage is a mechanical stage, which allows the control of the slides by moving the slides using the mechanical knobs on the stage instead of moving it manually. Aperture - This is a hole on the microscope stage, through which the transmitted light from the source reaches the stage. Microscopic Illuminator - This is the microscope’s light source, located at the base. It is used instead of a mirror. it captures light from an external source of a low voltage of about 100v. Condenser - These are lenses that are used to collect and focus light from the illuminator into the specimen. ■ They are found under the stage next to the diaphragm of the microscope. ■ They play a major role in ensuring clear sharp images are produced with a high magnification of 400X and above. ■ The higher the magnification of the condenser, the more the image clarity. ■ More sophisticated microscopes come with an Abbe condenser that has a high magnification of about 1000X. Diaphragm - it's also known as the iris. ■ It's found under the stage of the microscope and its primary role is to control the amount of light that reaches the specimen. ■ It's an adjustable apparatus, hence controlling the light intensity and the size of the beam of light that gets to the specimen. ■ For high-quality microscopes, the diaphragm comes attached with an Abbe condenser and combined they are able to control the light focus and light intensity that reaches the specimen. Condenser Focus Knob – this is a knob that moves the condenser up or down thus controlling the focus of light on the specimen. Abbe Condenser - this is a condenser specially designed on high-quality microscopes, which makes the condenser to be movable and allows very high magnification of above 400X. The high-quality microscopes normally have a higher numerical aperture than that of the objective lenses. The Rack Stop - It controls how far the stages should go preventing the objective lens from getting too close to the specimen slide which may damage the specimen. It is responsible for

preventing the specimen slide from coming too far up and hitting the objective lens.

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Organs are often sectioned to reveal their internal structure ○ Longitudinal Section - is a cut through the long axis of the organ ○ Cross section/Transverse section - is a cut at a right angle to the long axis ○ Oblique section - is a cut made across the long axis at other than a right angle

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Preparation of Tissue for Study ○ Fuck Dis CIET Sige Share Mo Lang

Steps in the Preparation of Tissue Section FIXATION

REAGENT’S/ EQUIPMENTS USED Formalin/ Formaldehyde

IMPORTANCE

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Increasing Concentration of alcohol

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CLEARING

Xylene

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INFILTRATION

Melted Paraffin Wax

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EMBEDDING

Melted Paraffin Wax

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TRIMMING

Scalpel

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SECTIONING

Microtome

WATER BATH

STAINING

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Hematoxylin & Eosin Stain (H&E Stain)

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After obtaining a fresh piece of cells or microorganisms from the body, it is rapidly placed in solutions of stabilizing or cross - linking compounds called fixatives. Fixation plays a huge role in preserving the tissue structure and preventing the degradation of enzymes released from an obtained specimen Fix the issue immediately after removal from the body 10% Formaldehyde Solution The fixed tissue must undergo dehydration before infiltration with such media. The process of dehydration is important because it immerses the specimen in an increasing concentration of alcohol to remove water and formalin (a widely used fixative) from the tissue. Removal of water using an increasing concentration of alcohol from 50% to 100%. In this process, the ethanol from the dehydration step is replaced by an organic solvent that is miscible with both alcohol and the embedded medium (Ex. Xylene). Clearing is an important step because it gives the tissue a translucent appearance. Making the tissue have a translucent appearance by removing the reagent prior to this process. Clearing agent is called xylene. Infiltration is an important step because it removes the organic solvent from the clearing step and replaces it with melted paraffin wax. The tissue is placed in this substance until it is infiltrated Filling in the holes of the tissue so that the tissue will not be destroyed in the trimming process. The holes are filled with melted paraffin wax In this step, the paraffin - infiltrated tissue is placed in a small mold with melted paraffin and allows it to harden. The paraffin surrounding the tissue will help in creating stability of the tissue so that it will be capable of being sectioned during microtomy The final product is a tissue block Still uses paraffin wax but you will now form a mold and make a tissue block. This step is a process where you remove the excess paraffin block to expose a tissue to a level where a section is obtained. It is usually trimmed at thickness between 10 and 30 μm. Used to exposed the tissue in the middle of the mold before proceeding to sectioning This step uses a microtome - a machine that cuts the tissue specimen into thin specimens in the form of ribbon that can be placed on a slide for microscopy. Most tissues are cut into 5 μm thickness. The tissue ribbon is placed in a water bath that has a controlled temperature which is at 60 degrees celsius. Then fish the tissue using a microscope slide. The microscope slide contains a Meyer’s Egg albumin which serves as adhesive so that the tissue ribbon will stick in the slide Staining is mostly done to make the appearance of the specimen more visible. Hematoxylin and eosin stain are used to make the tissue structure more visible and easy to observe and evaluate under the microscope. Hematoxylin - color purple; a form of basic dye which is take up by acidic component of cell specifically the nucleus

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Eosin - orange; an acid dye that is take up by basic component of cell like cytoplasmic organelles which are suspended in the cell’s cytoplasm

MOUNTING

Canada Balsam / Clear Nail Polish

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The next step, we need to put a drop of Canada Balsam or Clear Nail Polishon (an adhesive) into the specimen in a slide. Then cover the slide with a thin glass coverslip - take note that the coverslip must be free of optical distortion. Coverslip is put in the slide to prevent scratches of the specimen This is done to preserve the stained section of the specimen in the slide.

LABELLING

Pencil/ Label Marker

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Labelling the slide with the tissue specimen is an important step in tissue processing. This involves the patient's personal details that should match the details on the ordered test requisitions to avoid any delay in testing and results. cv

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WHAT IS A “CELL”? ○ Known as the basic unit of life BASIC FUNCTIONS OF CELLS ○ Cell metabolism and energy use ○ Synthesis of molecules [RER, SER, LIPID SYNTH, PROTEIN SYNT] ○ Communication [for nerve cells like neuron] ○ Reproduction & Inheritance [Sperm cell and Egg cell] Sperm Cell - the only cell that has the presence of flagellum RBC / Erythrocyte - The only cell in the body which does not contain a nucleus (unucleated cell) Plasma Membrane / Cell Membrane / Plasmalemma ○ Phospholipid Bilayer – “amphipathic” in nature [non-polar tail (long chain of fatty acids) / polar head (bears a phosphate group)] ○ Selective permeable boundary of the cell ○ Tail: Non-polar – hydrophobic/water repelling. Bears long chain of fatty acid/ lipid ○ Phosphate Head: Polar – hydrophilic/water attracting. Bears the phosphate group

Cytoplasm - serves as the bed. And it is coated by cell membrane. Cytosol is suspended in cytoplasm where cell organelles floats Cytosol

Viscous fluid medium which provides support to your cytoplasmic organelles

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Ribosomes ○ Composed of protein and rRNA; bound or free ■ Bound - nakadikit sa Rough ER ■ Free - suspended in cytosol

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Endoplasmic Reticulum ○ Smooth ER ■ ER Lacks bound polyribosomes ■ Fat (lipid) manufacture & production ■ Steroid & hormone production ○ Rough ER ■ Presence of polyribosomes ■ Production / folding / Quality Control & dispatch of proteins ■ How does quality control happen? From the command center of the cells, nucleus (bears DNA)

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Lysosomes ○ Sites of intracellular digestion and turnover of cellular components ○ Suicide bag of the cell. ○ Example, if you are infected by a bacteria, the lysosome will engulf the bacteria, which will be called phagolysosome. ○ After the bacteria is eaten by the lysosome, the lysosome itself will burst inside the cell and when it burst, the immune response will be triggered

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Mitochondria ○ Aerobic respiration and production of ATP ○ ATP - energy unit of the cell. ○ This is where ATP is produced

The nucleus contains the genetic material of the cell which is the DNA. The DNA according to the central dogma of microbiology, undergoes replication and it is transcribed to mRNA which is a process called transcription. mRNA, undergoes translation so that it will be translated into functional protein that the body needs. The nucleus contains its own nuclear membrane and the space between the nucleus and its membrane is called perinuclear space. Perinuclear Space is continuous up to the RER. and this is also where DNA Flows IF the protein is functional, the RER moves the protein via secretory vesicle palabas ng cell IF the protein is defective, the SER moves the protein into the cytosol so that it will be processed again.

Golgi Apparatus / Golgi Complex ○ Initiates packing, concentration and storage of secretory product The secretory product are the substances that is released from inside of your cell to outside

Secretory Granules / Vesicles ○ Transports cellular material ○ Secretory vesicles contains secretory granules

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Proteasomes ○ Degrades denatured or nonfunctional polypeptides

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Peroxisomes ○ Degrades and digest damaged or unneeded protein

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Cytoskeleton - Maintains intracellular structural support and organization of cells; facilitates movement of cell Microtubules - Maintains cell shape and rigidity Microfilaments (Actin Filaments) - Maintains cell shape Intermediate Filaments - Provides structural support; stabilized junctions between the cell

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Nucleus - Command Center of the cell

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Nuclear Envelope - Form a selectively permeable barrier between the nuclear and cytoplasmic compartments ○ Perinuclear Space - Nuclear envelope has two concentric membranes separated by this space this perinuclear space and the outer nuclear membrane is continuous with the RER ○ Nuclear lamina (inner nuclear membrane) - A highly organized meshwork of proteins Chromatin - Consists of DNA and all of the associated proteins involved in the organization and function of DNA Nucleolus - Subdomain of nuclei in cells actively engaged in protein synthesis. Presence of rRNA that is transcribed, processed, and assembled

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● Process of Cell Division Stages of mitotic cell divisions include: ● prophase, when chromosomes condense, the nuclear envelope disassembles, and the microtubular spindle forms; ● metaphase, when chromosomes are aligned; ● anaphase, when they begin to separate toward the two centrosomes; ● telophase, when a nuclear envelope re-forms around the separated chromosomes. ■ Telophase ends with cytokinesis or cell cleavage into two daughter cells by a contractile ring of actin filaments and myosin

TOPIC: M2 - THE EPITHELIAL TISSUE

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THE TISSUE

EPITHELIAL

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Main Characteristics of the 4 Basic Tissue Types Tissue

Cells

Extracellular Matrix

Main Functions

Epithelial Usually lines the surface of body cavities

Aggregated polyhedral cells

Small amount

Lining of surface or body cavities; glandular secretion

Connective usually support and protection

Several types of fixed and wandering cells

Abundant amount

Muscular contraction/mov ement

Elongated contractile cells

Moderate amount

Strong contraction; body movements

Nervous transmission of nerve, impulses or cel to cell communication

Elongated cells with extremely fine processes

Very small amount

Transmission of nerve impulses

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Support and protection of tissues/organs ●

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The basic tissues, each containing extracellular matrix (ECM) as well as cells, associate with one another in the variable proportions and morphologies characteristic of each organ. Most organs can be divided into: ○ Parenchyma – composed of the cells responsible for the organ’s specialized functions ○ Stroma - cells of which have a supporting role in the organ Epithelial tissues (Epithelium / Epithelia) - are composed of closely aggregated polyhedral cells (cells are intact) adhering strongly to one ...