Lecture 5 - Microscopy Flashcards
Magnification
Enlargement of an object
Resolution
How small and how close individual objects can be and still be recognized; puts a limit on useable magnification.
Numerical Aperature
The measure of the number of highly diffracted image-forming light rays captured by an object.
Increased NA Values=
Increased oblique rays are allowed to enter=
Increased resolution
Focal Length
The distance from an object being examined microscopically to the center of the objective lens of the microscope.
Working Distance
Distance between the bottom of the objective and the speciman being examined
Compound Light Microscope
A.K.A Brightfield microscope. Most commonly used in the clinical lab.
Brightfield with standard white light with no filters or manipulation.
Base of Microscope
Horseshoe platform where the entirety of the microscope rests
Arm of Microscope
Supports the microscope and adjusting systems - proper carrying point.
Stage of Microscope
Horizontal platform on which the object to be focused sits.
Light Source
Where the light originates (i.e. light bulb, etc.)
Rheostat
Adjusts the intensity of the light - varies depending on the user.
Condenser
Directs and focuses the beam of light from the light source on the material under examination. Positioned under the stage. Can be raised/lowered by using an adjustment knob.
Aperture Iris Diaphragm
Controls how much light passes through the material under observation.
Located beneath the lenses of the condenser. May correlate with the objective being used. Restricts amount of light passing through material as the objective gets larger.
Ocular (Eyepiece)
Magnifies the image formed by the objectives; viewing source for the user.
Most common magnification is 10x
Monocular –> one ocular
Binary –> two oculars
Interpupillary Distance
Distance between the two oculars (adjustable)
Diopter Adjustment
Adjustable focus of one of the oculars
Objectives
Responsible for primary image formation and magnification
Uses of 4x Objectives
Scanning - used to scan large material (insects, parasites, etc.)
Uses of 10x Objectives
Low Power
Uses of 40x Objective
High power/ High-Dry
Uses of 100x Objective
Oil (high power oil immersion)
Nose Piece
Mounts the objectives - should be used to rotate objectives.
Refractive Index
Describes how fast light moves through a material
Par-focal
When a specimen focused in the field of view for one microscope objectives remains focused when the nosepiece is rotated to bring another microscope obective into use (minor fine adjustments - ok)
Par-centric
Microscope objectives that are aligned so that a specimen centered in the field of view for one objective remains centered when the nose piece is rotated to bring another objective into use.
Magnification Calculation
Ocular x Objective
Light Path
(1) Light Source
(2) Aperture Iris Diaphragm
(3) Condenser Lenses
(4) Objective Lens
(5) Ocular Lens (eyepiece)
Coarse Adjustment (focus)
Rapid movement over a wide range; used to bring the 4x and 10x objectives into focus.
Fine Adjustment (focus)
Provides very slow movement over a limited range; used to fine-tune 4x and 10x, as well as bring 40x and 100x into focus.
How to care for a microscope when not in use.
- Covered and stored away
- 10x objective facing forward
- Stage lowered
Items to use when cleaning the exterior of the microscope
Gauze, lens paper, or kimwipes and gentle cleaning agent
Items to use when cleaning the oculars of the microscope
Lens paper and lens cleaner, and other material will scratch the lenses
Cleaning Objectives
Oil must be removed from the oil immersion (100x) objective
- Lower stage
- Use clean lense paper and lens cleaner
- Circular motion
Cleaning the Condenser
Lens paper and Lens cleaner
Stage and coarse/fine focus
Gauze, kimwipes, lens cleaner if needed
