Microscope PDF

MICROSCOPE PREPARED BY: LG DONGON, RN, LPT BELLWORK…… WHAT IS THE FUNCTION OF THE MICROSCOPE? LESSON OBJECTIVES: 1. to be able to label and give the function of each part of the microscope. 2. Use the microscope correctly to view slides and work out magnification. MICROSCOPY  isthe u...

MICROSCOPE PREPARED BY: LG DONGON, RN, LPT BELLWORK…… WHAT IS THE FUNCTION OF THE MICROSCOPE? LESSON OBJECTIVES: 1. to be able to label and give the function of each part of the microscope. 2. Use the microscope correctly to view slides and work out magnification. MICROSCOPY  isthe use of or investigation with a microscope.  the microscope uses glass lenses to magnify objects we are not able to see through our naked eye.  MICROSCOPE  an optical instrument used for viewing very small objects, such as mineral samples or animal or plant cells , typically magnified several hundred times. TWO TYPES OF MICROSCOPE 1. Simple Microscope 2. Compound Microscope SIMPLE MICROSCOPE  is nothing but a single biconvex lens. It referred to as a MAGNIFYING GLASS.  the object to be viewed in simple microscope is placed between the optic center and the focus.  image formed is erect, virtual and magnified. HISTORICAL DEVELOPMENT OF THE MICROSCOPE 1590- Hans Janssen and his son Zacharias Janssen, placed multiple lenses and found out that the objects through the tube appear greatly enlarged. 1609- Galileo Galilei invented a compound microscope using convex and concave lenses. Continuation: 1625- the first term microscope was used by Giovanni Faber to refer to the compound microscope of Galilei. 1665- Robert Hooke , an English physicist, coined the term cell in his publication Micrographia. -He was the first to see a plant cell under a single microscope. -the English Father of Microscopy Continuation: 1676- Antonie van Leeuwenhoek Was the first to see living cells using his own single lens microscope. He examined blood cells, yeast and insects.  1830- Joseph Lister reduced spherical aberrations by using several weak lenses together at certain distances to get a good magnification without blurring. 1874- Ernst Abbe introduced a mathematical formula that correlates resolving the power to the wavelength of light. It made the calculation of the theoretical maximum resolution of a microscope possible. 1931-Ernst Ruska and Max Knoll designed and built the first transmission electron microscope. The electron microscope does not depend on light but on electrons. It can visualize objects such as small as the diameter of an atom.  1932- Frits Zernike invented the first contrast illumination which allows imaging of transparent samples. Objects can be seen without staining. 1942- Ernst Ruska invented the first scanning electron microscope. It transmits a beam of electrons across the surface of the specimen. 1957-Marvin Minsky introduced the principle of confocal imaging which gives a resolution that is higher than that of conventional light. 1972- Godfrey Hounsfield and Allan Cornack developed the Computerized Axial Tomography (CAT) scanner. It can generate cross sectional views and three dimensional images of internal organs and structures. 1978- Thomas and Christoph Cremer developed the first practical confocal laser scanning microscope. This instrument focus laser beams to scan objects. 1981- Gerd Binnig and Heinrich Rohrer invented the scanning tunnelling microscope {STM}. It can visualize individual atoms within materials. 1986- Ernst Ruska won the Nobel Prize for his contribution to the study of microscopy. A nobel prize was also awarded to Gerd Binnig and Heinrich Rohrer.  1992- Douglas Prasher cloned the green fluorescent protein that he used in fluorescent microscopy. 1993-1996- Stefan Hall pioneered the first super resolution microscopy. 2010- Researchers at the University of California, Los Angeles used a cryoelectron microscope to see the atoms of the virus. 2014- Eric Betzig, Stefan Hell and William Moerner got the Nobel Prize in Chemistry for the super microscope they invented. It can see smaller than 0.2 um. MODERN MICROSCOPE TRANSMISSION ELECTRON MICROSCOPE (TEM) TOTAL MAGNIFICATION OCULAR LENS X OBJECTIVE LENS = TOTAL MAGNIFICATION EXAMPLE: 10X X 10X = 100 ( 100 times larger) Low power lens- it magnifies ten times and it is marked as 10x Highest power lens- can magnify forty times in a common compound microscope. Resolution- the ability of the microscope to show the details of an object being examined. Contrast- refers to the darkness of the background with reference to the specimen. PARTS OF A LIGHT MICROSCOPE MECHANICAL PARTS Parts of the microscope that are involved in giving support or strength to the instrument. These are also the parts that are movable and can be adjusted. BODY TUBE- a hollow tube through which light passes from the objective to the eyepiece. REVOLVING NOSEPIECE- holds the objectives. It can be rotated to select the appropriate objectives. The lenses must be “ clicked” into place to successfully view a specimen. ARM- connects the base and the body tube together. It serves as a handle for carrying the microscope. Continuation: STAGE- the platform where the slide or specimen to be examined is placed. It has an opening at the center that allows light to pass from the below the specimen. STAGE CLIP- holds the slide in place. BASE- the part where the microscope is firmly anchored. It gives support to the whole microscope and is the part where the illuminators are attached. INCLINATION JOINT- a joint found in microscopes at which the arm is attached to the pillar of the microscope. It is used for tilting the microscope. ILLUMINATING PARTS- parts of the microscope that provide and capture light illumination. MIRROR- reflects light from the surroundings to the specimen on the stage. -It is planar on one side and concave on the other. CONCAVE MIRROR – is used for natural light. FLAT SIDE/ PLANAR- used for artificial light. CONDENSER- concentrates the light from the light source or the mirror onto the object of specimen being studied. It is located below the stage , and it is held in place by a rack. IRIS DIAPHRAGM- regulates the amount of light that reaches the specimen. It is attached beneath the condenser. MAGNIFYING PARTS- parts of the microscope that are involved in magnifying the image of the specimens , including the resolution. EYEPIECE OR OCULAR- the part through which an observer looks to view a specimen. It usually has a magnification of 10x, though eyepieces with 5x to 30x magnification are also available. OBJECTIVES – the main lenses that magnify the specimen being observed. Usually microscopes have three objectives but modern ones house four or even five objectives.Typical objectives have magnifying powers of 4x, 10x, 40x, and even 100x. CELL THEORY 1665 ROBERT HOOKE- observe cells in cork.Coined the term cells Anton van Leeuwenhoek- created a powerful microscope 1827-33 ROBERT BROWN- noticed that pollen grains in water jiggled around called “ Brownian motion” - discovered nucleus HUMAN CHEEK CELL 1838- MATTHIAS SCHLEIDEN- a botanist who concluded that all plants are made of cells. 1839 THEODOR SCHWANN- a zoologist who concluded that all animals are made of cells. 1855 RUDOLph VIRCHOW- a physician who did a research on cancer cells and concluded “Omnis cellula e cellula “ All cells are from pre-existing cells. CELL THEORY  formally established by Theodor Schwann and Matthias Schleiden in 1839. The most basic tenet underlying the field of biology.  one of the basic principles of biology. Formulated by the 3 German scientists Theodor Schwann, Matthias Schleiden and Rudolph Virchow.  THE CELL THEORY STATES: 1. Cells are the smallest unit of life. All living things are composed of one or more cells.  they may be unicellular or multicellular. 2. Cells are the basic unit of organization of all organisms. 3. Cells come only from pre-existing cells.  they are derived from spontaneous generation Modern cell theory adds additional key points: 1. Cells carry and pass on to the offspring hereditary units during cell division. 2. All cells are relatively the same in terms of chemical composition and metabolic activity.  CELL NUMBER UNICELLULAR Are made of singe cell MULTICELLULAR Example: amoeba, bacteria Are made of million cells. chlamydomonas, yeast, euglena. Example: Plants and animals  CELL SIZE Cells are extremely small therefore they can be observed under microscope. Cells are measured in micrometers or microns. MYCOPLASMA- the smallest cell NERVE CELL- longest cell OSTRICH EGG- the largest cell  CELL SHAPE The shape of the cell varies in different organisms. The shape of plant cell is different from that of an animal cell. They may be - Spherical - polygonal - Oval - columnar or flat plate like - Elliptical - Spindle shaped - cuboidal