1.5: Correctly adjust and move the microscope (2023)

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All microscopes in the laboratory are parafocal. This means that when the slide is focused under the target, it basically stays in focus when the target changes. In practice, this means you typically only need to use the coarse focus button once per slide. Even if you change lenses, you can focus the slider just below the lower magnification lens (focusing is easier here) and use the fine focus knob there to make only minor adjustments.

When you first get a new slide, you can usually determine where the sample is by holding the slide. This pattern is usually a dot of color somewhere near the center of the coverslip. Once the slide is firmly secured to the stage using the stage clamps, use the stage control knob to move the paint until it is directly over the hole in the center of the stage through which the light passes. Now, if you look through the eyepiece with the lowest objective (always start with the lowest objective), you should be able to find and focus on the object quickly.

Occasionally, the eyepieces or objectives will have dirt or dust specks that make it difficult to focus on the sample. Always use the lens tissue provided by the lab supervisor or a clean cotton swab to clean the lens. Do not use other cloths or papers as they may scratch the lens. KimWipes are not lens wipes. Never use KimWipes on glass lenses or slides. To use lens tissue to remove dirt, first roll up the lens tissue and try to dry it. Remove dirt in a spiral motion, circling from the center of the lens outward. If that doesn't work, moisten a lens tissue or cleaning pad with blue lens cleaning fluid (don't apply the water directly to the lens) and clean the lens in a spiral motion, working from the center of the lens outward.

You can find a checklist for initial microscope setup here. This checklist should be used every time you get a new slideshow.

Lab 1 Exercise \(\PageIndex{1}\)

1. Plug in the microscope and turn on the light source.

2. Hold the microscope in your hand and place it within easy reach of the seat, with the open side of the table facing you

3. Rotate the lens so that the low power (smaller size) lens locks into place.

4. Visually inspect the slide to locate the sample.

5. Secure the slide with tent clips. The coverslip should be facing up on the slide. Locate the stage controls and make sure the slider moves smoothly side to side or up and down with the knob as you turn it.

6. Use the stage controls to move the slide so that the light source shines directly on the sample to be magnified.

7. Locate the coarse and fine focus buttons. While observing the scene and the lens, use the coarse focus knob to bring the lens as close as possible to the slide at low magnification.

What is the difference between a virtual image and a real image

The virtual image you see when you look into a microscope is not exactly the same as the actual image you see with your eyes. For one, it's bigger. On the other hand, the orientation of the images is different. The two lenses in a compound microscope reflect the original image twice in two different planes, magnifying it at the same time. So what you think is the "top" of the image is actually the bottom, and what you think is the "right side" is actually the left. Usually this does not pose a problem on a microscopic level, but it is important to understand how the microscope rearranges the virtual image.

Lab 1 Exercise \(\PageIndex{2}\)

Get an "e" slide. If it is already under the microscope, rotate the lower magnification objective into position, lower the coarse focus stage and remove the slide.
Visually observe the unmagnified "e" on the slide. Rotate the slider around your hand so the "e" is facing up. Now secure the slide to the microscope stage with the stage clamps so that the "e" is up and to your right when viewing with the naked eye.
In the right circle below, draw the "e" as it looks from the front up. Assume the circle below is the size of the entire cover. Without help, draw the "e" you see in the correct proportions of the cover. (The unmagnified "e" occupies a small portion of the coverage area.)
Mount the slide on the microscope stage with the "e" still facing up. Follow the checklist in Exercises 1-7 of Exercise 1 to ensure the microscope is properly set up for use, but stick to lower magnification objectives. Bring the "e" into your field of vision and focus.
In the upper left circle, draw what the "e" looks like when viewed through a microscope under a lower magnification lens. Write the overall magnification of the image below the circle.
How does a sample rotate when viewed under a microscope?
Look directly at the scene and draw (not through the eyepiece). Move the scene control knob to move the slider on the scene away from you, then move it back to its original position.
Now move the scene control knob the same way as before, but look at the "e" through the eyepiece. In which direction does the virtual image seem to move when the scene moves away from you?
Take another look at the scene and draw directly (not through the eyepiece). This time, move the Scene Control knob, move the slider to the right, and then move it back to its original position.
Now move the scene control knob the same way as before, but look at the "e" through the eyepiece. When the scene is moved to the right, in which direction does the virtual image appear to move?
The field of view is the entire area that can be seen when looking through the eyepiece. Use the scene control buttons to move the virtual image of "e" to one side of the field of view. Keep most of the "e", but move it to one side or the other.
Now switch to the next power goal. (Don't skip.) In which direction do you have to turn the target (clockwise or counterclockwise) to get to the next power target instead of the highest power target?
Use the fine focus button only (don't use the coarse focus button on anything but the bottom target) and focus on the "e".
What part of your field of vision do you magnify when moving to the next target?
Move away from the eyepiece and note the distance between the slide and the bottom of the lens. Spin back to target with low power. Now move on to the next goal (don't accidentally move to a higher power goal). Now turn to the third highest goal. What happens to the distance between the mount and the bottom of the lens when you switch to a higher performance lens?
How much space is there between the bracket and the bottom of the lens with the 3rd high performance lens still installed?
Note that when using coarse focus, there is a risk of damaging the objective on the bracket. Why is it indicated that you can only use low magnification lenses for coarse focus?
Only draw what you actually see. Even if you expect to see something, if it's not there, don't plan to see it. Don't base your plans on what a textbook or other source says you should go to. Don't draw on numbers that are expected in text or other sources unless you actually see them.

Create simple but accurate line drawings of enlarged samples

You don't have to be a great artist to create diagrams of the cells and structures you see under a microscope. You just need to be careful to draw something roughly the same size and shape as what you see. Please follow the instructions below:

Only draw what you actually see. Even if you expect to see something, if it's not there, don't plan to see it. Don't base your plans on what a textbook or other source says you should go to. Don't draw on numbers that are expected in text or other sources unless you actually see them.
Keep things as simple as possible. Draw strong, unbroken lines. Avoid shadows or cross-hatching unless there is a good reason to add them.
I like to simplify reality by omitting unnecessary details. Draw what interests you, but ignore background material, debris, or other distracting objects. Just make sure if you're leaving something out, it's not an essential part of your design.

You should always have a basic idea of what you're looking for before you start investigating. Tissue and other microscopic specimens can be confusing and confusing. In general, if you know what you're looking for, and sometimes more importantly, what you don't want, it will be easier to find what you want to design and make decisions about how to design it. design.

Keep in mind that what you see under a microscope may look very different from the perfect specimens often found in textbooks and diagrams on websites. Use an idealized image to find what you're looking for, but whatever your expectations, draw samples as they really are.

For example, in most textbooks neurons (the most common cells in nervous tissue) are drawn as a variant of the drawing in figure \(\PageIndex{1}\)A.

1.5: Correctly adjust and move the microscope (15)

In typical neuron diagrams seen in texts and websites, nuclei are often clearly visible, and are often seen as well. Sometimes organelles such as mitochondria are visible (there are no organelles in Figure \(\PageIndex{1}\)A). Dendrites are usually short and branched. There is almost always a single, easily identifiable axon that is longer than all dendrites and has branches at the end.

Figure \(\PageIndex{1}\)B shows a real neuron as seen through a microscope. Eventually, if you look at enough neurons through different types of microscopes, you can create a composite map that contains features from many samples to represent a "typical" neuron. However, if you look at individual neurons, it is unlikely that you will see everything in graph \(\ PageIndex{1}\)A. In fact, real-world examples often bear little resemblance to textbook examples. Draw what you see, not what you think you should see. Just make sure you're looking for what you're supposed to find (e.g. a neuron, not a piece of dirt or cell debris) and draw it as is.

In the case of a real neuron in graph \(\PageIndex{1}\)B, with no visible nucleus, there may be a large projection and a small projection that can be called a dendrite - but there are not many projections - and there is no Projected ones have no branches. There is a slender ledge, probably an axis, without branches.

If you graph what you see, you end up with the graph shown in Figure 1.14B. It doesn't look like a textbook neuron, but it's a reasonable representation of what's going on in this example.

1.5: Correctly adjust and move the microscope (16)

Most students feel that they "can't draw" and are unwilling to draw what they see under the microscope. You won't let a lack of artistic ability stop you.

Draw an outline close to the object you want to draw. Don't worry if it fits perfectly. almost fine
Try to get the proportions roughly correct. If an object is half or a third the size of another object, draw it that way in your drawing.
Don't draw everything you see. You'll actually get a better picture of the parts of the example you're interested in. You don't have to log every litter or grime. Identify important parts of the sample and record only those parts.
Do not use hatching or cross-hatching unless you have a good reason to do so. In fact, it's easier to understand your design if you only draw the outlines. Also, designing will be easier and faster.

Lab 1 Exercise \(\PageIndex{3}\)

1. Perform a human blood smear. Rotate the lower magnification objective into position on the microscope.

2. Follow the checklist \(\PageIndex{1}\) in the lab exercise until the blood smear is visible under the 40X objective.

3. You will see mostly red blood cells. They may be pink and the circles are seedless. Sometimes, some centers appear to have hollow circles, but these are not cores. If you look around the slide with the stage controls, you will find rare round nucleated cells. These are white blood cells. There are less than 1 white blood cell for every 100 red blood cells. These white blood cells may be light blue or gray with purple or dark blue nuclei. Your core isn't always round.

4. Among all the red blood cells, find the section on the slide with two or more white blood cells.

5. In the circle below, draw four or five representative red blood cells (don't draw all the red blood cells you see) and draw all the white blood cells in your field of view. Special care was taken to map the leukocyte nuclei as accurately as possible.

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6 Do not remove or reposition slides until one of your lab technicians has verified that your white blood cell collection is correct. Introduce yourself to a partner and ask for help.

Licensing and Attribution

CC licensed content, original

A&P laboratories. Author: Ross Whitvam. Provider: Mississippi University for Women. find next:http://www.muw.edu/.License: CC BY-SA: Attribution - Share Alike

Image \(\PageIndex{1}\)B. Graph graph of neurons in \(\PageIndex{1}\)A. Author: Ross Whitvam. Provider: Mississippi University for Women. find next:http://www.muw.edu.License: CC BY-SA: Attribution - Share Alike

Previously disseminated CC licensed content

Image \(\PageIndex{2a}\). A typical diagram of a neuron. Author: Jonathan Haas. Place:https://commons.wikimedia.org/w/inde...curid=18271454.License: CC BY-SA: Attribution - Share Alike

CC licensed content, specific performance

Figure \(\PageIndex{2b}\)A. A real neuron. Image \(\PageIndex{1}\)B. A real neuron. By W. Clay Spencer, Rebecca McWhirter, Tyne Miller, Punina Strasberg, Owen Thompson, Radina W. Hillier, Robert H. Waterston, David M. Miller III. it is at:http://dx.doi.org/10.1371/journal.pone.0112102.License: CC BY: Attribution

When storing the microscope, the following list should always be followed:

Take out any slides found in the scene and put them back in the slide case.
Rotate the smaller lens or don't rotate it to position it on the scene. Lower the stage a few turns.
Wrap the wire loosely around your hand, starting near the microscope and working your way towards the connector.
Hang the twine around the glasses.
Look at the numbers on the back of the microscope and put the box back in the numbered box.
If there is already a microscope in that numbered box, check its number and move it. If it's not numbered, just slide it onto the back of the box and place it near the front. We have some extra microscopes stored this way.