L1: Microscope Flashcards
1
Q
What is microscopy?
A
The science of investigating small objects and structures using a microscope.
2
Q
A magnifying glass used to magnify an object to a point where it can be seen by the human ey
A
Microscope
3
Q
Define microscopic.
A
Invisible to the eye unless aided by a microscope.
4
Q
In which century was the art of grinding lenses developed?
In what country and for what reason?
A
14th century.
Developed in Italy to improve eyesight
5
Q
Who made the first microscope?
A
Hans and Zacharias Janssen in 1590.
6
Q
What significant work did Robert Hooke publish in 1667?
A
Micrographia.
Robert Hooke studies various object with his microscope and publishes his results in Micrographia. Among his work was a description of cork and its ability to float in water
7
Q
Who is known as the Father of Microscopy?
A
Anton van Leeuwenhoek.
8
Q
He used a simple microscope with only one lens to look at blood, insects and many
other objects.
A
1675 – Anton van Leeuwenhoek (Father of Microscopy)
9
Q
What did Anton van Leeuwenhoek first describe?
A
Cells and bacteria.
10
Q
What technological advancement improved microscopes in the 18th century?
A
Lenses combining two types of glass to reduce chromatic effect.
11
Q
He reduced the problem with spherical aberration in 1830
A
Joseph Jackson Lister
12
Q
What did Joseph Jackson Lister demonstrate in 1830?
A
Using several weak lenses together at certain distances gave good magnification without blurring.
13
Q
What are the three structural parts of a microscope?
A
- Head
- Base
- Arms
14
Q
this part of the microscope carries the optical parts in the upper part of the microscope
A
Head
15
Q
acts as the microscope’s support; it also carries the microscopic illuminators
A
Base
16
Q
-the part that connects the base to the head and the eyepiece tube to the base of the microscope; it gives support to the head and used when carrying the microscope
A
Arms
17
Q
What is the function of the eyepiece or oculars?
A
Equipped with 10x lenses to magnify the intermediate image. They also limit the area of visibility
18
Q
Part of the microscope that prevents scratching of lens by the user’s eyeglass or vice versa
A
Eyepiece rubbers
19
Q
What is the function of the numbers on the eyepiece?
A
for differences in eye grading especially for
those wearing prescription glasses
20
Q
What is the purpose of the interpupillary control?
A
To adjust the lateral separation of the oculars for each individual.
21
Q
this part of the microscope provides a structural site of attachment for the revolving
nosepiece
A
Arm or neck
22
Q
What does the revolving nosepiece do?
A
Holds the objectives and allows for easy rotation between them.
23
Q
Functions of the Knob/screw at the back of the microscope
What happens if it is turned clockwise and counterclockwise?
A
⯍ Controls the height limit of the stage to prevent breakage of glass slides
⯍ Clockwise – to tighten the screw
⯍ Counterclockwise – to loosen the screw
⯍ For example, focus the slide using 40x objective then tighten the screw.
24
Q
What is the function of the inner knob before the coarse adjustment knob also known as the coarse tension adjustment knob
What happens if it is turned clockwise and counterclockwise?
A
⯍ Prevents the stage from going down and losing focus on the specimen
⯍ Clockwise - to tighten
⯍ Counterclockwise – to loosen
25
What do the numbers on the objectives refer to?
thickness of the coverslip to be used;
26
What should the coverslip be in relation with the objective used?
coverslip to be used must be compatible with the objective to be used for microscopic
examination
27
Most objectives have how many lenses
3 to 4
28
Scanner Objective (x)
Low Power Objective (x)
High Power Objective (x)
Oil Immersion Objective (x)
Scanner Objective (4x)
Low Power Objective (10x)
High Power Objective (40x)
Oil Immersion Objective (100x)
29
a hole on the microscope stage through which the transmitted light from the source reaches the stage
Aperture
30
What is the function of the mechanical stage?
Supports the prepared microscope slide for observation.
31
Function of the Mechanical stage knob
moves the stage by turning the knob left and right or backward and forward
32
this determines the positioning of the cells under the microscope; provides the coordinates or location of important cells
Stage numbers
33
What is the purpose of a stage clip
it keeps the slide stationary
34
focuses or directs the available light into the objective as it raised or lowered. Lowering this will increase the contrast of unstained specimens.
Condenser
35
What must the condenser numbers be?
| (What should be its value or what must it be the same with??)
It must be the same with the magnification of the objective for better viewing of the specimen details
36
What does the iris diaphragm regulate?
The amount of light that strikes the object being viewed. Adjustable through a moving lever
37
When is coarse adjustment knob and Fine adjustment knob used?
**Coarse adjustment knob** – used to focus with the low power objective only.
**Fine adjustment knob** – gives a sharper image after the object is brought into view with coarse adjustment; preferably used for HPO and OIO
38
What is the consequence of using the coarse adjustment knob with higher magnifications?
It can lead to damage or loss of focus on the specimen.
39
This part is located within the base. It is for adjustment of the illumination for brightness
Brightness adjustment knob/ Microscopic illuminator
40
a firm, horseshoe-shaped foot on which the microscope rests’. It contains the light or mirror
Base
41
What is working distance?
## Footnote
What is the relationship between magnification and working distance?
the distance between the objective and the
slide when objective is sharp focus.
## Footnote
The higher the magnification of the objective the shorter the working distance will be.
42
Different Types of Microscopes
- Compound/Upright
- Inverted
- Stereomicroscope
43
In a compound microscope, how does the objective lens face?
Downward, observing specimens from above.
44
This type of microscope is suitable for observation of glass slides or prepared slide and is used for routine microscopic examinations
Comound or Upright
45
What is the main feature of an inverted microscope?
The objective lens faces upwards, observing specimens from below.
46
This type of microscope is used for observation of culture container (stem cells/unstained cells)
Inverted Microscope
47
What does a Stereomicroscope have and how is it used?
2 separate light path, enables observation of specimen from different angles at both eyes
48
A type of microscope suitable for animal works and large sample imaging because it allows 3D observation of sample
Stereomicroscope
49
APPLICATIONS OF THE
MICROSCOPE
❑ BRIGHT FIELD MICROSCOPY
❑ DARK FIELD MICROSCOPY
❑ PHASE CONTRAST MICROSCOPY
❑ ELECTRON MICROSCOPY
▪ (TEM)
▪ (SEM)
50
The simplest of all the optical microscopy illumination techniques iin which Specimen’s image appears dark against a bright background
BRIGHTFIELD MICROSCOPY
51
What is the usual light source of brightfield microscopy and what type of microscopes are generally used with it?
Light source is usually tungsten lamp. Generally used with compound microscopes
52
The Ability to distinguish between two adjacent points in brightfield microscopy
Resolving Power
53
The resolving power of brightfield microscopy depends on two factors which are?
White light and Numerical aperture
54
What is white light in brightfield microscopy?
| (what is it composed of)
Composed of a mixture of colored lights of various
wavelengths
55
What is numerical aperture in brightfield microscopy?
Expression relating to the cone of light that
is delivered to the specimen by the condenser and gathered by the objective
56
What is total magnification in brightfield microscopy?
the ocular magnification multiplied by the objective magnification
57
Microscopy that uses a special optic system which converts differences in phases into differences in intensity such that some structures appear darker than the others
Phase Contrast Microscopy
58
What does Phase Contrast Microscopy reveal?
The gross details of the internal structures in a living cell
59
What does dark field microscopy do?
Makes objects appear brilliantly illuminated against a black background.
60
A Microscopy used to demonstrate spirochetes which are difficult to observe in transmitted light
Darkfield Microscopy
61
A microscopy that develops an image resulting from variable electron density of the specimen interposed in the electron beam
Transmission Electron Microscope
62
Transmission Electron Microscope produces what type of images?
monotone, two-dimensional, high magnified images
63
What is the resolving power of a Transmission Electron Microscope (TEM)?
0.001 um which is 200x that of light microscopes
64
What conditions must specimens be when TEM is used? (3)
Specimens must be fixed, stained and dried
65
TEM in Electron microscopy is used to observe what?
Used to observe internal ultra-structural detail of cells and observations of viruses or small bacteria
66
What is the practical limit of resolution of SEM in electron microscopy?
0.005um or five-fold less than
that of TEM
67
What type of images does a Scanning Electron Microscope (SEM) produce?
Monotone, tri-dimensional images.
## Footnote
by detection at a 90 degrees angle of secondary electrons emitted from the specimen surface as a result of bombardment by the primary electron beam
68
What electron microscopy is used to observe the surface details of structures?
SEM
69
What are the consequences and should be done if the microscope is located too close to mechanical appliances that can cause external vibrations?
**Consequences:** Blurred image because of vibrations
**Treatment:** Remove the microscope from the source of vibration. Use a strudy table as a support or use a vibration proof table
70
Consequences and Treatment if a Microscope is located near a window
**Consequences:** Bright light from the
window prevents correct focusing
**Treatment:** Set up the microscope
near a wall. Position the microscope in such a way that the overhead light falls slightly in
front of the microscope
71
Consequences and Treatment if a Microscope is located in a place where the room light enters the eyepiece
**Consequences:** Room light or flares are
reproduced on the photo
**Treatment:** * Cover the eyepiece with caps. Shut out stray light getting into the eyepiece or the focusing telescope by changing the optical path selector
72
Consequences and Treatment if a Microscope is located in a dusty and dirty
room; placed near window where the dust
can enter from the outside.
**Consequences:** Black spots are
reproduced on the specimen image
**Treatment:** Set up the microscope
in another room. Cover the whole microscope with a dust proof covering
73
Microscope Handling and Storage when work is completed
| (What should you do after; in order)
lower the stage,
remove the slide,
rotate in the lowest power objective,
wrap the cord loosely around the base and cover with a dust cover.
Take care not to wrap the cord around a hot (built in) light source.
74
Always keep your microscope ________ when not in use. Optics and mechanical parts must be protected from _____.
Always keep your microscope **covered** when not in use. Optics and mechanical parts must be protected from **dust**.
75
What is the proper way to handle a microscope when moving it?
One hand under the base and the other hand gripping the arm or frame.
76
In storing microscopes, keep them away from?
vibration, moisture, high temperatures and direct sunlight.
77
Why should you never store microscopes in chemical storage areas?
corrosive fumes may
damage metal and lenses
78
In microscope maintenance, you need to treat lenses with great care because?
they can be easily scratched. Never use anything abrasive.
79
What is the first step in cleaning microscope lenses? What should be done next?
Blow away any dust with a blower brush.
Then use lens tissue and lens cleaning fluid to clean the objectives and eyepieces.
**Do not use paper towel or regular tissues, as they will scratch the lens. Do not use other solvents**
80
How should eyepieces or objectives be cleaned?
Do not remove eyepieces or objectives from their location but clean only their external surfaces
81
How should the oil immersion objective be cleaned?
Remove immersion oil from the 100x objective immediately after use with lens tissue and lens cleaning fluid
82
Wipe dust off the body of the microscope with a?
damp cloth
83
Why should you never attempt to take a microscope apart? Instead, what should be done?
This could impair operation, efficiency and accuracy.
Have the microscope serviced regularly by a professional, as most microscopes require periodic lubricating and minor adjustment of their mechanical parts.
84
How should bulbs in microscopes be replaced?
Follow your user’s manual for instruction in replacing the bulb.
Always allow a bulb to cool before replacing it.
When replacing bulbs avoid touching the glass with your hands, use a tissue.
Fingerprints can reduce bulb quality and reduce its life.
85
Possible causes when a common fault of not light occurs
* Power cord is not connected, power switch is off
* Wrong bulb is installed
* The bulb has burnt out
* Light intensity control is turned down too low
* Objective is not properly in position
* If using the 100x objective immersion oil has not been applied
86
Possible causes when a common fault of image being too dark occurs
* Increase light intensity
* Sub-stage iris diaphragm is not open
enough
* Condenser is too low
87
Possible causes when a common fault of image being too light occurs
* Decrease light intensity
* Sub-stage iris diaphragm is open too much
88
Possible causes when a common fault: Spot in the field of view that doesn’t move when the slide is moved occurs
Lens is dirty. Clean both the
objective and eyepiece.
89
Possible causes: Poor image quality, poor resolution, image not sharp (100x oil objective)
* Clean objective, eyepiece and
condenser
* Check if immersion oil is
contaminated or cloudy or air
bubbles are present
* Slide is wrong way up
90
Possible causes: Poor image quality, poor resolution, image not sharp (40x objective)
There is dirt or oil on the lens
91
Possible causes when there is uneven illumination
* Adjust condenser
* Make sure objective has clicked
into place
92
Possible causes when there is flickering light
* Bulb needs replacement
* Loose connection at the outlet
* Bulb not properly inserted
* Check voltage supply
93
Possible causes when half the viewing field is illuminated
Make sure the objective is clicked
into place
94
Possible causes when unable to focus the slide
* Coverslip is too thick
* Slide is the wrong way up
* The stage is slowly dropping, adjust tension of coarse adjustment knob
* Clean the slide, objective and eyepiece
95
What can cause a blurred image in a microscope?
External vibrations from nearby machinery.
96
Fill in the blank: The _______ is used to focus with the low power objective only.
Coarse adjustment knob.
97
What is the total magnification of a scanning objective (4x) with a 10x ocular lens?
40x.
98
True or False: The iris diaphragm may be adjusted by a movable lever.
True.
99
What materials should never be used to clean microscope lenses?
Paper towel or regular tissues.
100
What should you do if the image is too dark?
Increase light intensity.
101
What is the purpose of the brightness adjustment knob?
To adjust the illumination for brightness.
102
What happens if the immersion oil is not applied when using the 100x objective?
The objective is not properly in position.
103
What is the function of the mechanical stage knob?
To manipulate the object being observed.
104
What should you do if the viewing field is unevenly illuminated?
Adjust the condenser.
