PRELIM 01 - Microscopy Flashcards
Equivalent of meter to inches
39.4 inches
The sizes of bacteria and protozoa are usually expressed in terms of __________
micrometers (µm)
A typical spherical bacterium (coccus) is approximately __________ in diameter
1 µm
A typical rod-shaped bacterium (bacillus) is approximately __________ wide × __________ long.
1 µm; 3 µm
Is an instrument used to see objects that are too small for the naked eye
Microscope
The science of investigating small objects using such an instrument
Microscopy
Means invisible to the eye unless aided by a microscope
Microscopic
Microscope that uses single lens
Simple light microscope
Microscope that uses set lenses or a lens system
Compound light microscope
Parts used for adjustments and support
Mechanical parts
Parts used to enlarge the specimen
Magnifying parts
Parts used to provide the light
Illuminating parts
Ability of the lens to distinguish two objects that are close together
Resolution
A function of objective lenses and its ability to gather light
Numerical aperture
2 components of numerical aperture
n, sinθ
Refractive index of the medium the lens is working in (Components of numerical aperture)
n
Measurement of the cone light that enters the objective (Components of numerical aperture)
sinθ
Resolving power - Compound microscope
200 nanometers
Resolving power - Scanning electron microscope
10 nanometers
Resolving power - Transmission electron microscope
0.2 nanometers
Degree of enlargement; no of times the length, breadth, or diameter of an object is multiplied
Magnification
Useful magnification
500x-1000x
Empty magnification
1400x and beyond
Occurs when the image continues to be enlarged, but no additional details are resolved
Empty magnification
Formula for magnification
Objective lens x Eyepiece lens
Refers to objectives that can be changed with minimal or no refocusing
Parfocal
Distance from the front lens element of the objective to the closest surface of the coverslip when the specimen is in sharp focus
Working distance
Is the extent of the observable area in distance units
Field of view (FOV)
Formula for field of view
Field number ÷ Objective magnification
Used to measure minute distances or the apparent diameters of objects which subtend minute angles
Micrometer
Used only at very large magnifications that require high resolving power
Oil immersion objective (OIO)
Magnification of up to 300 times; used to look at opaque objects or objects that are too large to be viewed with a compound microscope (Type of microscope)
Stereo (Dissecting) microscope
Uses a laser light to scan samples that have been dyed (Type of microscope)
Confocal microscope
Uses electrons rather than light for image formation (Type of microscope)
Scanning electron microscope (SEM)
Uses electrons in creating a magnified image (Type of microscope)
Transmission electron microscope (TEM)
Bottommost portion that supports the entire/lower microscope (Mechanical parts of a microscope)
Base
Part of the base that supports the other parts (Mechanical parts of a microscope)
Pillar
Allows for tilting of the microscope for convenience of the user (Mechanical parts of a microscope)
Inclination joint
Curved/slanted part which is held while carrying the microscope (Mechanical parts of a microscope)
Arm/Neck
Attached to the arm and bears the lenses (Mechanical parts of a microscope)
Body tube
Cylindrical structure on top of the body tube that holds the ocular lenses (Mechanical parts of a microscope)
Draw tube
Platform where object to be examined is placed (Mechanical parts of a microscope)
Stage
Secures the specimen to the stage (Mechanical parts of a microscope)
Stage clips
Allows the light to pass through the specimen for the better view (Mechanical parts of a microscope)
Stage opening/Aperture
This is also known as the body; it caries the optical parts in the upper part of the microscope (Mechanical parts of a microscope)
Head
When turned, it raises or lowers the eyepiece in order to adjust the focus for each eye (Mechanical parts of a microscope)
Diopter adjustment
Rotating disc where the objectives are attached (Mechanical parts of a microscope)
Revolving/Rotating nosepiece
Lies atop the nosepiece and keeps dust from settling on the objectives (Mechanical parts of a microscope)
Dust shield
Geared to the body tube which elevated or lowers when rotated bringing the object into approximate focus (Mechanical parts of a microscope)
Coarse adjustment knob
A smaller knob for delicate focusing bringing the object into perfect focus (Mechanical parts of a microscope)
Fine adjustment knob
Elevates and lowers the condenser to regulate the intensity of light (Mechanical parts of a microscope)
Condenser adjustment knob
Lever in front of the condenser and which is moved horizontally to open/close the diaphragm (Mechanical parts of a microscope)
Iris diaphragm lever
Gathers wavefronts from the microscope light source and concentrate them into a cone of light (Illuminating parts of a microscope)
Condenser
Controls the amount of light reaching the specimen (Illuminating parts of a microscope)
Iris diaphragm
Located beneath the stage and has concave and plane surfaces to gather and direct light in order to illuminate the object (Illuminating parts of a microscope)
Mirror
A built-in illuminator beneath the stage that may be used if sunlight is not preferred or is not available (Illuminating parts of a microscope)
Electric lamp
Another set of lens found on top of the body tube which functions to further magnify the image produced by the objective lenses (Magnifying parts of a microscope)
Ocular/Eyepiece
Metal cylinders attached below the nosepiece and contains especially ground and polished lenses (Magnifying parts of a microscope)
Objectives
4 types of objectives
Scanner, LPO, HPO, OIO
Gives the lowest magnification, usually 10x
Low power objective (LPO)
Gives higher magnification, usually 40x or 43x (Magnifying parts of a microscope)
High power objective (HPO)
Gives the highest magnification, usually 97x or 100x, and is used wet either with cedar wood oil or synthetic oil (Magnifying parts of a microscope)
Oil immersion objective (OIO)
Provides observers with about enough magnification for a good overview of the slide; has a 4x magnification (Magnifying parts of a microscope)
Scanner
3 limitations of light microscope
Resolution, Wavelength, Numerical aperture