What is a Manual Microtome?
A
manual microtome is a precision instrument used in histology to cut extremely thin slices of tissue, known as sections. These sections are essential for microscopic examination, allowing researchers and pathologists to study the fine details of tissue structure and function.
How Does a Manual Microtome Work?
The manual microtome employs a sharp blade that moves across a tissue block, slicing it into thin sections. The tissue block is typically embedded in a medium like paraffin to stabilize it. The operator turns a handwheel, which advances the tissue block towards the blade in precise increments, allowing for consistent section thickness.
Types of Manual Microtomes
There are several types of manual microtomes, each suited for different applications. The most common types include the rotary microtome, the sliding microtome, and the sledge microtome. The
rotary microtome is widely used for routine histological work due to its precision and ease of use. The sliding microtome is ideal for larger, harder specimens, while the sledge microtome is used for cutting extremely hard or large tissue blocks.
Why Use a Manual Microtome?
Manual microtomes offer several advantages, including cost-effectiveness, simplicity, and reliability. They are often preferred in laboratories where budget constraints exist or where automation is not necessary. Despite the advent of automated microtomes, manual versions remain invaluable for specific applications and provide a high degree of control over section thickness.
Preparation of Tissue Blocks
Proper preparation of tissue blocks is crucial for obtaining high-quality sections. Tissues are typically fixed to preserve their structure, then dehydrated and embedded in paraffin wax. The embedded tissue is then mounted on a microtome chuck. The quality of the embedding medium and the precision of the embedding process significantly influence the quality of the final sections.Sectioning Technique
Sectioning with a manual microtome requires skill and practice. The operator must adjust the angle of the blade, the thickness of the sections, and the speed of cutting. Common issues include compression, tearing, and chatter marks, which can be minimized with proper technique and maintenance of the microtome.Blade Maintenance and Handling
The blade of a manual microtome must be kept extremely sharp to produce clean sections. Regular honing and stropping are necessary to maintain the blade's edge. Handling the blade with care is also critical to avoid accidents and ensure the longevity of the blade.Applications in Histology
Manual microtomes are used in a wide range of histological applications, from routine diagnostic pathology to advanced research. They are employed in the study of various tissues, including
brain tissue,
liver tissue, and
muscle tissue. The ability to produce thin sections makes it possible to visualize cellular and subcellular structures, aiding in disease diagnosis, research, and educational purposes.
Conclusion
Despite the availability of automated alternatives, manual microtomes continue to be a staple in histology laboratories due to their precision, versatility, and cost-effectiveness. Mastery of this essential tool allows for the production of high-quality tissue sections, which are fundamental for microscopic examination and analysis.
