Slides for university students are usually prepared in the histology lab. Students in medical sciences are often trained to know what a tissue is when placed on a slide. The essence is for them to be able to identify anomalies or deviations from the standard ones. However, before they can start taking any of the required lectures, the lab technologists must take the tissues through some histology techniques to prepare microscope slides.
There are different kinds of microscopes the students can use in the lab. The ones to be used should depend on what they will be asked to identify as well as the conditions in the laboratory. They include the electron, light, phase contrast, fluoresce, confocal microscopes.
For example, the light microscope has a lamp, the iris, diaphragm, tube with lenses, eyepiece, objective lens and adjustment knobs which of three types: condenser height, coarse and fine knobs. They all perform the function of adjusting the clarity of the slides in view.
The tissues that will be placed under the microscope must be processed before they can be used. There are different techniques to do this and they include fixation, dehydration, clearing, waxing, embedding, and staining. The use of chemicals applies in these steps and they have to be in the required amount if the tissue is going to be well prepared or last long.
When the cell dies, it is going to start decaying almost immediately but this can be avoided by fixation. Fixation is therefore a step taken to prevent putrefaction so that the tissue can still be useful. Fixatives to use for this purpose include Bouin's fluid, salt, and buffered formalin while alternative methods are refrigeration and heating. When fixatives are used, the volume should be in the proportion of 75 percent to 25 percent. The quantity of the fixative should be more than the tissue so that it can be well soaked.
After fixing, the next step is dehydration. The essence of dehydrating is to remove water from the tissue. To do this, alcohol is used in ascending grades. That is, you can use 50%, 50%, 75%, 75%, 98% and 98% in that order. Maintaining this gradual ascent is important. When dehydration is not done properly, it can cause bubbles to exist and the tissue can distort after shrinking.
After dehydrating the tissue, the alcohol has to be removed and this can be done by the process called clearing. It can be done with clearing agents such as xylene, benzene, toluene, and chloroform. Afterward, impregnate with wax to remove xylene. Apart from removing the xylene, waxing makes cutting easy and the quality of the cuts to be strong.
The slides that will be viewed should not contain wax. Thus, it should be removed by the process of rehydration. Rehydration is done with alcohol in descending grades; that is from absolute to 50 percent. Water can be reintroduced since the tissue must be brought back to water. Staining is the final process in the technique and the stains used depends on the tissue and what should be identified. They include Periodic Acid Schiff, Sudan black, Van Gieson and Osmium tetroxide.
There are different kinds of microscopes the students can use in the lab. The ones to be used should depend on what they will be asked to identify as well as the conditions in the laboratory. They include the electron, light, phase contrast, fluoresce, confocal microscopes.
For example, the light microscope has a lamp, the iris, diaphragm, tube with lenses, eyepiece, objective lens and adjustment knobs which of three types: condenser height, coarse and fine knobs. They all perform the function of adjusting the clarity of the slides in view.
The tissues that will be placed under the microscope must be processed before they can be used. There are different techniques to do this and they include fixation, dehydration, clearing, waxing, embedding, and staining. The use of chemicals applies in these steps and they have to be in the required amount if the tissue is going to be well prepared or last long.
When the cell dies, it is going to start decaying almost immediately but this can be avoided by fixation. Fixation is therefore a step taken to prevent putrefaction so that the tissue can still be useful. Fixatives to use for this purpose include Bouin's fluid, salt, and buffered formalin while alternative methods are refrigeration and heating. When fixatives are used, the volume should be in the proportion of 75 percent to 25 percent. The quantity of the fixative should be more than the tissue so that it can be well soaked.
After fixing, the next step is dehydration. The essence of dehydrating is to remove water from the tissue. To do this, alcohol is used in ascending grades. That is, you can use 50%, 50%, 75%, 75%, 98% and 98% in that order. Maintaining this gradual ascent is important. When dehydration is not done properly, it can cause bubbles to exist and the tissue can distort after shrinking.
After dehydrating the tissue, the alcohol has to be removed and this can be done by the process called clearing. It can be done with clearing agents such as xylene, benzene, toluene, and chloroform. Afterward, impregnate with wax to remove xylene. Apart from removing the xylene, waxing makes cutting easy and the quality of the cuts to be strong.
The slides that will be viewed should not contain wax. Thus, it should be removed by the process of rehydration. Rehydration is done with alcohol in descending grades; that is from absolute to 50 percent. Water can be reintroduced since the tissue must be brought back to water. Staining is the final process in the technique and the stains used depends on the tissue and what should be identified. They include Periodic Acid Schiff, Sudan black, Van Gieson and Osmium tetroxide.
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