EXERCISE 1: THE MICROSCOPE

Importance of microscope

Brings organisms or microorganisms within the range of the human eye as well as parasites, fungi, etc.

Compound microscope

Commonly used today; can magnify up to 1000 times

Electron microscope

Can magnify up to One Million times

How to hold the microscope properly?

Make sure to hold the Arm and Base

The dominant hand should hold the Arm while the other hand should hold the bottom of the Base

depending on the microscope you are using, you might have to plug a loose cord on both the microscope and the outlet OR if you have a scope that is attached to the microscope, you can just unwind the cord and plug to the outlet

Arm

Connects to the base and supports the microscope’s head

is used to carry the microscope

Base

Is used for support still for carrying the microscope

Light switch

Located at the back of the microscope or at the back

Is used to turn on and off the microscope

Adjusting light level to increase contrast

1. Illuminator (light source)

2. Iris Diaphragm

Light/Brightness Adjustment knob and Illuminator (light source)

Understanding how to adjust the amount of light that is shining through your specimen is an extremely important skill to have, so too much light and your specimen can be washed out. So what would appear under the microscope is that it would be too bright if there is too much light, appearing in white background.

Too little light and there’s not enough illumination to see the organism or microorganism.

Adjust the light in order to manipulate the contrast. That’s the difference between the visibility of your specimen versus the background.

Use the brightness adjustment knob to adjust and control the amount and intensity of light passing in the microscope. The light source is located at the base of the microscope.

Iris Diaphragm

Another way that your scope allows you to adjust the amount of light shining up through the specimen or regulates the amount of light passing through the stage

Located directly beneath the stage (Squarish platform)

How to manipulate the Iris?

You have to move it to open and close the iris diaphragm. The iris, therefore, controls the amount of light reaching the specimen so it regulates the amount of light that passes through the stage and it is used to vary the intensity and size of the light that is projected upward into the slide

Stage and stage clip

Stage control

Fine and coarse adjustment knobs

Ocular lenses or eyepiece

Objective lenses

Parts of a Mechanical Stage

Stage

It is the platform and where the specimen or slide is mounted. This is where organisms are placed fro observation.

Stage clip

Holds the slide in place. It is important since we are moving the stage together with the slide, forward, backward, and sidewards

Stage controls

The thing that controls the stage

Fine and coarse adjustment knob

Are both used to focus the microorganism

Coarse adjustment knob

Brings the specimen into focus by raising or lowering the stage.

NEVER use the coarse focus or coarse adjustment knob on high power objective or oil immersion objective because it can heat the specimen and can crash the lens into the the slide

Focuses the image under low power only

Bigger knob and inner portion

Fine adjustment knob

Sharpens the image under all powers

Usually the smaller knob

Manipulates the outer portion of the and final tuning of the image (little movement)

For little movements

Ocular lenses or Eyepiece

Where you will look through in order to see the specimen under the microscope. Magnify specimen up to 10x

Open both eyes to refrain from getting Eye strain

In a compound microscope, it can be either singular or a set of binocular lenses

Objective lenses

Has 4:

Scanner

Low power

High power

Oil immersion objective

Hold or contain the objective lenses, we use this to rotate the objective lenses into a place over the opening in the stage.

Purpose of Nosepiece and objective lenses

There will be a clicking sound

How to know if objective lens is correctly placed?

Red band

Scanner objective. 4x magnification. It magnifies the specimen four times its actual size

Yellow band

Low power objective. Magnifies the specimen 10x its actual size.

Blue band

High power objective. Magnifies the specimen 40x its actual size

Black band

Oil immersion objective. Magnification of 100x

TOTAL MAGNIFICATION= (magnification of the ocular lens) (magnification of the objective)

Formula for Total magnfication

NEVER adjust the Coarse adjustment knob because it would have a coarse or bigger movement. At the very least, it would take the specimen out of focus or it could smash the objective and slide itself

What to do when using high power as there are two long lenses (longest lenses)

Revolving nosepiece

Made of rubber; Used when rotating the objectives or manipulate it, not the objectives itself (it makes the objective loose or damage the lenses)

Common Mistake: Holding the objective, and the objective may be loose and damage the lenses.

Parfocal lens

Objectives can be changed with minimal or no refocusing. If you focused on the scanner and changed to LPO, you would have the minimal refocusing using the adjustment knob

OIO (Oil Immersion Objective)

Called Oil immersion since you have to put a drop of CEDAR OIL on top of the light or slide wherein there’s light

Working Distance

The distance between the lens and the slide

Candida Albicans

Part of a normal/natural microflora of humans. Found in the human digestive tract, mouth, vagina, etc. they are opportunistic fungal pathogens. They are fungi specifically the yeast

Fungi can be a yeast or a mold, so Candida albicans is under the yeast.

Responsible for candidiasis and they are described to have a shape or a morphology of oval or spherical bodies.

Field

Entire circle

● Important to put the scope properly so as to not damage it so make sure the shortest objective lens is pointing down the scanner.

● Lower the coarse adjustment knob all the way down so the lens won't smash into the stage

● Make sure the stage is clean and the lens are clean and dry also

● Wipe the oil with cotton when using OIO. Handkerchiefs or towels are not allowed since it may scratch the lenses

● Clean the microscope before and after use

● Switch off, unplug, return it to the counter properly by coiling the cord and putting it back into the eyepiece.

● Carry the microscope properly. Dominant in the arm, non-dominant on the base and close to the body for it to be stable

● Some have cover so put the cover

How to properly put away your microscope

Compound microscope

What type of microscope are we using?

Artificial light

Does a compound microscope use natural or artificial light?

Concave lens; it converges the light rays on the object

What lens is used in artificial light? How?

Candidiasis (Yeast infection)

An infection caused by Candida Albicans

Coarse and Fine adjustment knobs

What are the 2 adjustment knobs?

Coarse- Brings the stage upwards and downwards

Fine- used to sharpen image; Coarse should not be used in HPO and OIO

When do we use the 2 adjustment knobs

2000x

If you have an ocular lens of 20x and using an OIO, how much is the total magnification?

Dominant hand at the arm while the other hand is at the base

How you hold the microscope properly

Oval or spherical in shape, formed in clusters, and purple

What is the morphology of Candida Albicans

Revolving nosepiece

What are the objective lenses attached to?

1000x

What is the total magnification for OIO?

Coarse adjustment knob

What is known as the “bigger knob”?