Lecture 5 - Microscopy

Question 1

Magnification

Answer 1

Enlargement of an object

Question 2

Resolution

Answer 2

How small and how close individual objects can be and still be recognized; puts a limit on useable magnification.

Question 3

Numerical Aperature

Answer 3

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

Question 4

Focal Length

Answer 4

The distance from an object being examined microscopically to the center of the objective lens of the microscope.

Question 5

Working Distance

Answer 5

Distance between the bottom of the objective and the speciman being examined

Question 6

Compound Light Microscope

Answer 6

A.K.A Brightfield microscope. Most commonly used in the clinical lab.

Brightfield with standard white light with no filters or manipulation.

Question 7

Base of Microscope

Answer 7

Horseshoe platform where the entirety of the microscope rests

Question 8

Arm of Microscope

Answer 8

Supports the microscope and adjusting systems - proper carrying point.

Question 9

Stage of Microscope

Answer 9

Horizontal platform on which the object to be focused sits.

Question 10

Light Source

Answer 10

Where the light originates (i.e. light bulb, etc.)

Question 11

Rheostat

Answer 11

Adjusts the intensity of the light - varies depending on the user.

Question 12

Condenser

Answer 12

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.

Question 13

Aperture Iris Diaphragm

Answer 13

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.

Question 14

Ocular (Eyepiece)

Answer 14

Magnifies the image formed by the objectives; viewing source for the user.

Most common magnification is 10x
Monocular –> one ocular
Binary –> two oculars

Question 15

Interpupillary Distance

Answer 15

Distance between the two oculars (adjustable)

Question 16

Diopter Adjustment

Answer 16

Adjustable focus of one of the oculars

Question 17

Objectives

Answer 17

Responsible for primary image formation and magnification

Question 18

Uses of 4x Objectives

Answer 18

Scanning - used to scan large material (insects, parasites, etc.)

Question 19

Uses of 10x Objectives

Answer 19

Low Power

Question 20

Uses of 40x Objective

Answer 20

High power/ High-Dry

Question 21

Uses of 100x Objective

Answer 21

Oil (high power oil immersion)

Question 22

Nose Piece

Answer 22

Mounts the objectives - should be used to rotate objectives.

Question 23

Refractive Index

Answer 23

Describes how fast light moves through a material

Question 24

Par-focal

Answer 24

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)

Question 25

Par-centric

Answer 25

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.

Question 26

Magnification Calculation

Answer 26

Ocular x Objective

Question 27

Light Path

Answer 27

(1) Light Source
(2) Aperture Iris Diaphragm
(3) Condenser Lenses
(4) Objective Lens
(5) Ocular Lens (eyepiece)

Question 28

Coarse Adjustment (focus)

Answer 28

Rapid movement over a wide range; used to bring the 4x and 10x objectives into focus.

Question 29

Fine Adjustment (focus)

Answer 29

Provides very slow movement over a limited range; used to fine-tune 4x and 10x, as well as bring 40x and 100x into focus.

Question 30

How to care for a microscope when not in use.

Answer 30

• Covered and stored away
• 10x objective facing forward
• Stage lowered

Question 31

Items to use when cleaning the exterior of the microscope

Answer 31

Gauze, lens paper, or kimwipes and gentle cleaning agent

Question 32

Items to use when cleaning the oculars of the microscope

Answer 32

Lens paper and lens cleaner, and other material will scratch the lenses

Question 33

Cleaning Objectives

Answer 33

Oil must be removed from the oil immersion (100x) objective

• Lower stage
• Use clean lense paper and lens cleaner
• Circular motion

Question 34

Cleaning the Condenser

Answer 34

Lens paper and Lens cleaner

Question 35

Stage and coarse/fine focus

Answer 35

Gauze, kimwipes, lens cleaner if needed