PRELIM LAB MICROSCOPY Flashcards
● Instrument for viewing objects that are too small to be seen by the naked/unaided eye
● Greek micron = small; scopos = aim
MICROSCOPE
● The SCIENCE OF INVESTIGATING SMALL OBJECTS using such an instrument
MICROSCOPY
● 1590 - 1st microscope was probably constructed by
Zacharias Jansen
Separated objective, eyepiece and source of light
1665 - Robert Hook’s microscope
invented simple microscope
1676 - Antonie van Leeuwenhoek
initiated the mass production of
microscopes
1847 - Carl Zeiss
1st electron microscope was constructed
1933
○ Degree of enlargement
○ No. of times the length, diameter, of an object is multiplied
MAGNIFICATION
○ Ability to reveal closely adjacent structural details as separate and distinct
○ A measure of the clarity and level of detail in the image
RESOLUTION
○ Lenses can be interchanged with minimal adjustment of focus
○ Similar focal points in the same plane
○ Most microscopes are designed to be
parfocal
PARFOCALITY
○ Objects appear dark against a light
background
○ Routinely used in the clinical laboratory
BRIGHT - FIELD MICROSCOPE
○ Objects appear bright against a dark
background
○ Replaces the condenser with a condenser that contains opaque disk
○ For Treponema pallidum
DARK - FIELD MICROSCOPE
○ For low refractive index
○ Allows visualization of transparent/unstained specimen
PHASE CONTRAST MICROSCOPE
○ Has a changed order of optical parts & source of light
■ Optics is under slide and light source is above
INVERTED MICROSCOPE
○ Allows visualization of naturally fluorescent microorganism or those stained by a fluorescent dye including labeled antigens & antibodies
FLUORESCENCE MICROSCOPE
○ Creates high-contrast, high-resolution
images, particularly in thick specimens
○ A laser light source is typically used to
illuminate the specimen
CONFOCAL MICROSCOPE
○ Optical parts contains special NICOL
PRISMS to generate a beam of polarized light -> observation of structures (chitin, cellular fibers, crystalline cell inclusions
○ Birefringent images appear bright/colored against a black background
POLARIZED MICROSCOPE
○ Uses electron beams allowing much higher resolution & the ability to visualize smaller structures
○ Transmission EM: 2D image
○ Scanning EM: 3D image
ELECTRON MICROSCOPE
LIGHTING PARTS
○ Light Source
○ Condenser
○ Diaphragm
MECHANICAL PARTS
○ Arm
○ Base
○ Nosepiece
○ Stage
○ Coarse & Fine adjustment knobs
OPERATION IN THE MICROSCOPE VIEW
- QUADRANTS
- CONCENTRIC CIRCLES
- ACCORDING TO CLOCK FACE
circle, pericentric, & peripheral circle
CONCENTRIC CIRCLES
- optical field is divided clockwise into 4
quadrants
QUADRANTS
TYPES OF SLIDE PREPARATIONS:
- a new clean slide is slightly pressed on the surface of the examined tissue & attached cell are observed (cells of liver/brain)
Impression preparations
a small drop of suspension containing cells is placed near an end of a slide & is spread across the slide by the edge of another slide (blood smear)
SMEAR
containing cell suspensions/processed histology tissue covered by cover slip
COVERED SLIDES
