Lab+1+Microscopy.pdf

BIO102 Laboratory MICROSCOPY WEEK 1 MICROSCOPY is the technical field of using microscopes to view samples & objects that cannot be seen with the unaided eye (objects that are not within the resolution range of the normal eye). It is the stud...

BIO102 Laboratory MICROSCOPY WEEK 1 MICROSCOPY is the technical field of using microscopes to view samples & objects that cannot be seen with the unaided eye (objects that are not within the resolution range of the normal eye). It is the study of science using a microscope. MICROSCOPE The microscope is a powerful tool for investigating the complexity of biological life. This includes looking at the identity and structure of microorganisms, which is essential in the diagnosis of many infectious diseases. Microorganisms are not visible to the human eye, owing to their small size. MICROSCOPY Microorganisms are miniscule organisms that cannot be seen with the naked eye Discovery of microscope has led to their close observations Development of the Microscope - In the earliest history humans noticed that when certain foods spoiled they became inedible or caused illness, and yet other “spoiled” foods did not harm and even enhance flavor  Development of the Microscope - Several centuries ago, there was already a sense that diseases such as the black plague and small pox were cause of such phenomena were vague, because technology to study them was lacking  Development of the Microscope True awareness of the widespread distribution of microorganisms and some of their characteristics was finally made possible by the development of the First Microscopes - Hans and Zacharias Janssen, ~1590 inventor of the earliest microscope. Development of the Microscope The earliest record of microbes is in the works of Englishman Robert Hooke in the 1660s. Hooke studied a great diversity of material form household objects, plants and trees Development of the Microscope Hooke described spots of mold he found on the sheepskin cover of a book Drawing of “hairy mold” colony made by Robert Hooke in 1665 The drawing of Hooke is a fungus species of Mucor (a common indoor mold) Development of the Microscope ANTON VAN LEEUWENHOEK (1632-1723) Leeuwenhoek constructed more than 250 small powerful microscopes that could magnify up to 300 times Considering that he had no formal training in science, his descriptions of bacteria and protozoa (which he called “animalcules”) were precise Development of the Microscope ANTON VAN LEEUWENHOEK (1632-1723) - father of microbiology - Wrote over 100 papers on his discoveries for both Riyal Society of England and the French Academy. Microscopy - compound microscope It is a type of microscope that contains more than one magnifying lens Microscopy - compound microscope It can magnify 1000x Visible light is its main source of illumination Microscopy - compound microscope Consist of 2 magnifying lens system Eyepiece (or ocular) – this contains ocular lens that has magnifying power of 10x Microscopy - compound microscope Second lens system is located in the objectives that is positioned directly above the organism to be viewed  MICROSCOPY 2 COMPOUND LIGHT MICROSCOPE 1. With Mirror to direct an external light source o Used to observe and study organisms and microscopes. o Were the earliest type of microscope invented and the most widely used compound microscope today. MICROSCOPE 2. With built-in light microscope - is a microscope that uses multiple lenses to enlarge the image of a sample. - viewing samples at high magnification (40 - 1000x) - two sets of lenses: the ocular lens (in the eyepiece) and the objective lenses (close to the sample). Microscopy Parts Microscopy Functions o Eyepiece (ocular lens) with or without Pointer: The part that is looked through at the top of the compound microscope. Eyepieces typically have a magnification between 5x & 30x. o Monocular or Binocular Head: Structural support that holds & connects the eyepieces to the objective lenses. o Arm: Supports the microscope head and attaches it to the base. o Nosepiece: Holds the objective lenses & attaches them to the microscope head. This part rotates to change which objective lens is active. o Base: Bottom base of the microscope that houses the illumination & supports the compound microscope. Microscopy Functions o Objective lenses: There are usually 3-5 optical lens objectives on a compound microscope each with different magnification levels. 4x, 10x, 40x, and 100x are the most common magnifying powers used for the objectives. The total magnification of a compound microscope is calculated by multiplying the objective lens magnification by the eyepiece magnification level. So, a compound microscope with a 10x eyepiece magnification looking through the 40x objective lens has a total magnification of 400x (10 x 40). o Specimen or slide: The object used to hold the specimen in place along with slide covers for viewing. Most slides & slide covers are thin glass rectangles. o Stage or Platform: The platform upon which the specimen or slide are placed. The height of the mechanical stage is adjustable on most compound microscopes.  Microscopy Functions o Stage clips or mechanical stage: Clips on the stage that hold the slide in place on the mechanical stage. o Aperture - Disc or Iris Diaphragm: Circular opening in the stage where the illumination from the base of the compound microscope reaches the platform of the stage. o Abbe Condenser: This lens condenses the light from the base illumination and focuses it onto the stage. This piece of the compound microscope sits below the stage & typically acts as a structural support that connects the stage to arm or frame of the microscope. o Coarse and fine adjustment controls: Adjusts the focus of the microscope. These knobs increase or decrease the level of detail seen when looking at the slide or specimen through the eyepiece of the compound microscope. Microscopy Functions o Stage height adjustment: Adjusts the position of the mechanical stage vertically & horizontally. It is important to adjust these knobs so that the objective lens is never coming into contact with the slide or specimen on the stage. o Mirror: Reflects light into the base of the microscope. Earlier microscopes used mirrors that reflected light into the base of the microscope instead of halogen bulbs as their source of illumination. o Illumination: Light used to illuminate the slide or specimen from the base of the microscope. Low voltage halogen bulbs are the most commonly used source of illumination for compound microscopes. o Bottom Lens or Field Diaphragm: Knob used to adjust the amount of light that reaches the specimen or slide from the base illumination.  ACTIVITY 1 MICROSCOPY  BIO102 LABORATORY THANK YOU Presentation by Princess Mae Peria