MICROSCOPY (MICROPARA LEC/LAB)

27問 • 1年前

問題一覧

DIFFERENT TYPES OF MICROSCOPES • also known as the COMPOUND LIGHT MICROSCOPE • contains more than one magnifying lens • can magnify objects approximately a THOUSAND times their original size. • VISIBLE LIGHT is its main source of illumination. • OPTICAL AND MECHANICAL PARTS

COMPOUND MICROSCOPE

• or ocular • contains what is called the ocular lens that has a magnifying power of 10x

EYEPIECE

• is located in the objective that is positioned directly above the organism to be viewed.

SECOND LENS SYSTEM

Topmost part of the microscope which is the lens the viewer looks through to see the specimen

OCULAR LENS

Located above the stage, it holds the objective lenses.

REVOLVING NOSE PIECE

It connects the eyepiece to the objective lenses.

BODY TUBE

Connects the body tube to the base of the microscope.

ARM

brings the specimen into general focus

COARSE ADJUSTMENT

It fine tunes the focus and increases the details of the specimen

FINE ADJUSTMENT

This is held in place above the stage by the revolving nosepiece - the lenses that are closest to the specimen. - It contains 3 to 5 objectives ranging in power from to 100X.

OBJECTIVE LENSES

Located beneath the revolving nosepiece, it is the flat platform on which the specimen is placed

STAGE

Situated above the stage, these are metal clips that hold the slide in place.

STAGE CLIPS

hole in the middle of the stage that allows light from the illuminator to reach the slide containing the specimen

APERTURE

switch located at the base of the microscope that turns the illuminator on or off.

ON/OFF SWITCH

The light source of the microscope.

ILLUMINATOR

Found on the condenser, it is used to adjust the amount of light coming through the condenser.

IRIS DIAPHRAGM

It is found beneath the stage - contains a lens system that focuses light onto the specimen. - It gathers and focuses light onto the specimen.

CONDENSER

It supports the microscope it is where the illuminator is found

BASE

DIFFERENT TYPES OF MICROSCOPE • Made up of a series of lenses and utilizing VISIBLE LIGHT as its source of illumination • can magnify an object 1,000 to 1,500 times • to visualize BACTERIA AND FUNGI • Objects less than or thinner than 0.2 μm cannot be visualized by this type of microscope • The term “brightfield” is derived from the fact that the SPECIMEN APPEARS DARK AGAINST THE SURROUNDING BRIGHT VIEWER FIELD of this microscope. • it has VERY LOW CONTRAST • most of the cells need to be stained to be properly viewed

BRIGHTFIELD MICROSCOPE

DIFFERENT TYPES OF MICROSCOPES • utilizes REFLECTED LIGHT instead of transmitted light • with a special condenser that ONLY THE SPECIMEN IS ILLUMINATED • The specimen to be studied APPEARS BRIGHT AGAINST A DARK BACKGROUND • ideal for studying specimens that are: - unstained or transparent - absorb little or no light • useful in examining the external details of the specimen such as its outline or surface • used to view SPIROCHETES

DARKFIELD MICROSCOPE

DIFFERENT TYPES OF MICROSCOPES • first introduced by Frits Zernike, a Dutch physicist, in 1934. • has a CONTRAST ENHANCING OPTICAL TECHNIQUE in order to produce HIGH CONTRAST images of specimens that are transparent which include: • thin tissue slices • living cells in culture subcellular particles • such as nuclei and organelles

PHASE CONTRAST MICROSCOPE

DIFFERENT TYPES OF MICROSCOPES • makes use of ultraviolet light and fluorescent dyes called FLUOROCHROMES. • The specimen under study FLUORESCES OR APPEARS TO SHINE AGAINST A DARK BACKGROUND • can be used to : • visualize structural components of small specimens such as cells • to detect the viability of cell populations • may also be used to visualize the genetic material of the cell (DNA and RNA)

FLUORESCENCE MICROSCOPE

DIFFERENT TYPES OF MICROSCOPES • Also known as the ———— LASER SCANNING microscope (CLSM) or laser ———- scanning microscope (LCSM) • uses an OPTICAL IMAGING TECHNIQUE that INCRESEAS OPTICAL RESOLUTION and contrast of the micrograph • specimen is STAINED WITH A FLUORESCENT DYE to make it emit or return light • object is scanned with a LASER into planes and regions • This is used, TOGETHER WITH COMPUTERS • to produce a THREE DIMENSIONAL IMAGE • also useful in the study of CELL PHYSIOLOGY

CONFOCAL MICROSCOPE

DIFFERENT TYPES OF MICROSCOPES • utilizes a BEAM of ELECTRONS to create an image of the specimen. • first prototype of this microscope was built by the German Engineer Ernst Ruska in 1933 • had a resolution power of up to 50 nm. • Modern electron microscopes are capable of magnifying objects up to 2 MILLION TIMES • used to visualize VIRUSES and SUBCELLULAR STRUCTURES of the cell.

ELECTRON MICROSCOPE

TYPES OF ELECTRON MICROSCOPE • Is the ORIGINAL form of the electron microscope. • TWO dimensional, black and white images • Magnifies objects up to 200,000 TIMES

TRANSMISSION ELECTRON MICROSCOPE

TYPES OF ELECTRON MICROSCOPE • can magnify bulk samples with greater depth of view so that • image produced represents the 3D STRUCTURE of the sample, but the image is still only black and white. • magnify the object 10,000 TIMES.

SCANNING ELECTRON MICROSCOPE

DIFFERENT TYPES OF MICROSCOPES • developed in the 1980s by the Swiss scientists Dr. Gerd Binnig and Dr. Heinrich Rohrer • used to study the MOLECULAR and ATOMIC SHAPES of organisms on a NANOSCALE

SCANNING PROBE MICROSCOPE

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