In this lab, we discussed preparation of a wet mount slide. Research and describe another slide preparation and an example of when it would be used.
Answers
Answer:
Used for aquatic samples, living organisms and natural observations, wet mounts suspend specimens in fluids such as water, brine, glycerin and immersion oil. A wet mount requires a liquid, tweezers, pipette and paper towels.
To prepare the slide:
Place a drop of fluid in the center of the slide
Position sample on liquid, using tweezers
At an angle, place one side of the cover slip against the slide making contact with outer edge of the liquid drop
Lower the cover slowly, avoiding air bubbles
Remove excess water with the paper towel
Although wet mounts can be used to prepare a significantly wide range of microscope slides, they provide a transitory window as the liquid will dehydrate and living specimens will die.
Organisms such as protozoa may only live 30 minutes under a wet mount slide; applying petroleum jelly to the outer edge of the cover slip creates a seal that may extend the life of the slide up to a few days.
In addition, larger protozoan such as paramecium may be too large and/or move too quickly under the wet mount.
In these circumstances, adding ground pieces of cover glass to the water before the slip layer will create added space and chemicals or strands of cotton can be added to slow the movement of paramecium, amoeba and ciliates.
Smear Slides:
Smear slides require two or more flat, plain slides, cover slips, pipette and tissue paper:
Pipe a liquid sample such as blood or slime onto a slide
Using the edge of the second slide, slowly smear the sample creating a thin, even coating
Put a cover slip over the sample, careful not to trap air bubbles
Remove excess liquid
Ideally, smears should dry naturally in an environment of moderate, steady temperature.
The angle of the smearing slide determines the length of the smear; a steeper angle creates a shorter smear. For samples such as blood, begin by backing the smearing slide into the sample and then push across the slide, pulling the blood in the opposite direction to create a smooth layer.
A thicker slide can be created with two drops, but only with the blood of mammals as the erythrocytes lack a nucleus allowing cells to be amassed in multiple layers.
Read further about Blood Smears - process and technique, possible presence of artifacts
Squash Slides:
Designed for soft samples, squash slides begin by preparing a wet mount; place lens tissue over the cover glass; gently press down, careful not to destroy the sample or break the cover glass, and squash the sample; remove excess water.
Staining:
A variety of methods exist for staining microscope slides, including non-vital or in vitro stains of non-living cells and vital or in vivo stains of living tissue. Staining provides contrast through color that reveals structural details undetected in other slide preparations.
Staining solutions such as iodine, methylene blue and crystal violet can be added to wet or dry mounts.
A simple staining method:
Add a drop of staining solution on the edge of one side of the cover slip
Position the edge of a paper towel on the opposite end
Allow dye to be pulled across the specimen
Stains are especially useful in the fields of histology, virology and pathology, allowing researchers to study and diagnose diseases, identify gram positive and negative bacteria as well as examine detailed attributes of a variety of cells.
See different staining types and preparation techniques for more information.
Prepared Slides
Especially useful for educational purposes and for those who do not want to undertake the laborious process of creating slides, prepared microscope slides are available in all areas of science, including:
Biology
Plants
Animals
Single-cell organisms
preparing microscope slides
Human Anatomy
Organ samples
Tissues
Blood
Epithelium cells
Botany
Monocot and Dicot Tissues
Zoology
Samples from various animal species
Marine-biology
Bacteria
Algae
Coral
Fish and Crustaceans
Pathology
Bacteria
Virus
Diseased tissue
Prepared microscope slides also offer access to bacteria, animal tissue, marine life, diseased cells and other specimens that may not be easily available to students or hobbyists.
In addition, they can be used as controls for students and researchers to compare collected samples.
Prepared slides can be purchased in sets and are almost always permanent, providing indefinite reuse.
Whether you mount samples, pipette into wells or use prepared slides, microscope slides offer a vehicle to contain a specimen while observing under magnification.
Illuminated on the stage of a compound light microscope, an amazing new view into the world can be seen with the simple act of placing a sample on a glass slide.
Explanation: