Microscopy & Care and Use of the Microscope PDF

TOPIC 1 & 2: Introduction to Microscopy & Care and Use of the Microscope Michelle Charina C. Gomez Learning Objectives | Topic 1 Identify the different parts of the microscope Know the function of each part of the microscope Understand how the mechanism contributes to magnific...

TOPIC 1 & 2: Introduction to Microscopy & Care and Use of the Microscope Michelle Charina C. Gomez Learning Objectives | Topic 1 Identify the different parts of the microscope Know the function of each part of the microscope Understand how the mechanism contributes to magnification and resolution Learning Objectives | Topic 2 Understand the proper care and maintenance of a microscope Identify the essential parts of a microscope and their functions Demonstrate proper handling techniques  TOPIC 1 Introduction to Microscopy Microscopy Technical field of using microscopes to view samples and objects that cannot be seen with the unaided eye ○ Objects that are not within the resolution range of the normal eye Light microscope An essential device in the field of histology ○ The study of the microscopic anatomy of cells, tissues, and organs ○ Allows for the visualization of tissue structure and changes that the tissue may have undergone Original microscope - uses sunlight as light source Modern microscopes - uses electric bulbs or light emitting diodes (LEDs) Light microscopy | General Principle Light source produces a beam of light focused on the tissue section or sample → transmitted light passes through a set of objective lenses → passes through an eyepiece → into the eye of the microscopist Fundamental Concepts | Magnification Enlarging the appearance of an object Achieved through the objective lenses and the eyepiece lens Enlargement is quantified by a calculated number called magnification ○ Example: a microscope with a magnification of 100x can make an object appear 100 times larger than the actual size Fundamental Concepts | Resolution The ability of a microscope to distinguish two objects that are close together as distinct objects rather than just one Fundamental Concepts | Magnification & Resolution Both photos are of the same magnification but different resolutions Parts of a microscope Three Structural Parts of the Microscope Part Function Head A cylindrical metallic tube that holds the eyepiece lens at one end and connects to the nose piece at the other end. It connects the eyepiece to the objective lens. Arm The part connecting the base to the head and the eyepiece tube to the base of the microscope Base The lowermost part of the microscope that supports the entire microscope structure Optical Structural Parts of the Microscope Part Function Eyepiece Lens closest to the viewer’s eye and is located at the top of the microscope; commonly of 10X or 15X magnification. Diopter Adjustment Present only in binocular microscope to correct differences in vision of the two eyes. Nosepiece Movable circular structure that houses all objective lenses; also called revolving turret. Stage Section where the specimen is placed for viewing. Optical Structural Parts of the Microscope Part Function Stage Control Knob Used to move the stage mechanically. One knob moves the stage from left to right, whereas the other one moves the stage backward and forward. Light source Shines light on the specimen Condenser Lenses that are used to collect and focus light from the illuminator into the specimen Diaphragm Also known as the iris; found under the stage and controls the amount of light that reaches the specimen Optical Structural Parts of the Microscope Part Function Light switch An electrical control device used to turn on and off the light source Brightness adjustment Controls the voltage to the light source, hence controlling the intensity (brightness) of the light bulb Optical Structural Parts of the Microscope | Objective lenses The lens closest to the specimen and fitted on the nosepiece Collects and unites the maximum amount of light possible from the object to form a high-quality magnified real image Objective lenses of a standard microscope and their magnification power: ○ 4X - scanning ○ 10X - low power objective ○ 40X - high power objective ○ 100X - oil immersion objective (OIO) Color coded and of different sizes Optical Structural Parts of the Microscope | Total Magnification Obtained by multiplying the magnification of the eyepiece lens and objective lens Optical Structural Parts of the Microscope | Adjustment Knobs These are control knobs used to focus the microscope on the specimen Fine adjustment knob ○ Used for fine adjustment ○ Smaller knob used to sharpen the image ○ Mostly used while viewing under high power Coarse adjustment knob ○ Used for focusing the image under low power magnification ○ Larger knob ○ Raises or lowers the stage rapidly  TOPIC 2 Care and Use of the Microscope Light Microscope Requires attention to care to maintain its optimal performance The high number of components a microscope has makes it more prone to frequent troubleshooting and repairs Routine microscope checks can uncover issues that may affect the quality of images obtained from the microscope Factors that can affect Microscope Performance Smear of immersion oil applied in dry objective lens Presence of the following in the lenses: ○ Dirt ○ Dust ○ Scratches  Procedure | Preparation 1. Position the microscope on a flat and stable surface 2. Look for any noticeable damage or loose parts. Avoid using a damaged microscope 3. If the microscope has been stored, thoroughly clean the lenses to avoid dust and debris a. Using a lens cloth or lens cloth  Procedure | Adjusting the Microscope 1. Use the coarse adjustment knob to adjust the stage of the microscope. 2. Look through the eyepiece and use the coarse adjustment and fine adjustment knob to focus on the specimen. 3. Adjust the interpupillary distance to match your eye width for comfortable viewing. 4. Rotate the nosepiece to select the desired objective lens. Start with the lowest magnification for initial observation. Scanning (4x), Low (10x), High (40x), and Oil Immersion (100x)  Procedure | Handling 1. Hold the microscope with both hands, one on the arm and the other supporting the base. 2. Don't touch the lenses with your fingers. To carefully wipe the lenses, use lens paper or a cloth drenched with lens cleaning solution.  Procedure | Maintenance & Storage 1. Clean the microscopes and place low power objectives over the stage. 2. Store the microscope in a clean, dry environment away from direct sunlight and extreme temperatures with appropriately secured cords. 3. Refer to the microscope manual for specific maintenance instructions and troubleshooting tips. References Dahal, P. (2024, May 26). Parts of a microscope with functions and labeled diagram. Microbe Notes. Retrieved from https://microbenotes.com/parts-of-a-microscope/ LibreTexts Biology. (n.d.). Magnification and Resolution. Retrieved from https://bio.libretexts.org/Bookshelves/Microbiology/Microbiology_(Boundless)/03%3A_Mi croscopy/3.01%3A_Looking_at_Microbes/3.1D%3A_Magnification_and_Resolution#:~:text =Magnification%20is%20the%20ability%20to,two%20objects%20from%20each%20other. Science Learning Hub. (n.d.). Magnification and Resolution. Retrieved from https://www.sciencelearn.org.nz/resources/495-magnification-and-resolution Suvarna, S., Layton, C., & Bancroft, J. (2019). Bancroft’s Theory and Practice of Histological Techniques (8th ed.). Elsevier.