Microscope Parts, Types & Uses PDF

Kirkuk University Microbiology Dept. Pr. Med. Biology 1st stage Microscope; parts, types and uses. Kvan Omar M.Sc. Fall 2023 Introduction to Microscope The microscope is a valuable instrument that magnifi...

Kirkuk University Microbiology Dept. Pr. Med. Biology 1st stage Microscope; parts, types and uses. Kvan Omar M.Sc. Fall 2023 Introduction to Microscope The microscope is a valuable instrument that magnifies the image of many small objects or details of objects which cannot be seen by the unaided human eye and making them visible to the human eye. Microscopes are used to observe the shape of bacteria, fungi, parasites and host cells in various stained and unstained preparations. The earliest evidence of magnifying glass forming a magnified image dates back to 1021 when the physicist ibn al-haytham (965–1039) published the “book of optics. It was Antony Van Leeuwenhoek (1632-1723), a Dutch draper and scientist, and one of the pioneers of microscopy who in the late 17th century became the first man to make and use a real microscope. Parts of a typical compound microscope with their uses; 1. Eyepiece or ocular lens: the lens, present at the top and is used to see the objects under study, contains a magnification of 10X or 15X. 2. Tube: Tube or the body tube, connects the eyepiece to the objective lenses. 3. Objective lenses: 3 or 4 objective lenses are found on a microscope, with ranges of 4X, 10X, 40X and 100X powers. 4. Diaphragm: helps in controlling the amount of light. 5. Coarse adjustment knob: Used for focus on scanning. 6. Fine adjustment knob: for focusing at the high power lens. 7. Arm: It supports the tube of the microscope. 8. Stage: The platform that is flat used for placing the slides under observation. 9. Stage clip: Stage clips hold the slides in proper place. 10. Condenser: focusing the light on the specimen under observation. Presence of condenser lens gives a sharper image. 11. Base: Provides basal support for the microscope. 12. Power switch: The main power switch that turns the illumination on or off. Parts of a typical compound microscope Types of Microscope Microscopes used in clinical practice are compound light microscopes. They are called light microscopes because they use a beam of light to view specimens. A compound light microscope with a single eye-piece is called monocular; one with two eye-pieces is said to be binocular. Microscopes that use a beam of electrons (instead of a beam of light) are called electron microscopes. 1. Light microscope: 1.1 Bright-field microscope: This is the commonly used type of microscope. In brightfield microscopy the field of view is brightly lit so that organisms and other structures are visible. It is mainly used with stained preparations. 1. Light microscope: 1.2 Dark-field microscope: In darkfield microscope a special condenser is used which make the field of view dark and the organisms are illuminated. A special condenser is used which causes light to reflect from the specimen at an angle. 1. light microscope: 1.3 Phase-contrast microscope: Phase-contrast microscope allows the examination of live unstained organisms which special condensers and objectives are used. Used in Microscopic observation of unstained biological material 1.4 Fluorescence microscope:  In fluorescence microscopy specimens are stained with fluorochromes.  Light of high energy is then used to excite molecules within the specimen or dye molecules attached to it.  Used to the study of living cells and tissues. Types of Microscope: 2. Electron microscope: Beam of electrons used as source of illumination instead of light, and magnetic lens instead of glass lens, their magnification power about 100,000x or higher because the electron have much shorter wavelength than the photon of normal light. There are tow types of electron microscope: 1. Transmission electron microscope (TEM). 2. Scanning electron microscope (SEM). SEM vs. TEM