Name: Jenra D.
Eran BSMT 3 D
ACTIVITY 6: Study Questions
1. What is the purpose of trimming the specimen?
- Trimming the specimen is an essential step in the tissue preparation process, particularly
after the tissue has been embedded in a block of paraffin or resin. The purpose of
trimming is to expose the tissue area of interest by removing excess embedding medium
around the specimen. This ensures that the tissue surface is readily accessible for
sectioning, allowing smooth, clean cuts during microtomy. By removing unnecessary
embedding material, trimming also helps to improve the visibility of the specimen for
examination, enabling better analysis under the microscope. Moreover, proper trimming
ensures that the block has a uniform shape and size, which makes sectioning more
efficient and reduces the risk of block instability or uneven cutting. Lastly, trimming
allows the specimen to be aligned correctly in the block, which is crucial for cutting
sections with the desired plane of orientation.
2. What are the precautionary/safety procedures to follow during trimming?
- Use Protective Equipment:
Always wear appropriate personal protective equipment (PPE), including gloves, safety
goggles, and a lab coat, to prevent injury from sharp instruments and exposure to chemicals.
- Handle Sharp Instruments with Care:
Trimming involves the use of sharp knives, microtomes, or other cutting tools. Always handle
these instruments carefully to avoid cuts. Use tools with handles that provide a secure grip to
minimize the risk of accidental slips.
- Proper Ventilation:
When trimming paraffin or resin blocks, ensure the work area is well-ventilated, especially if
you are using heated surfaces or solvents. Fumes from melted paraffin or other chemicals can
be harmful if inhaled.
- Check Equipment Condition:
Inspect the trimming instruments (e.g., microtome blades) regularly for wear or damage. A dull
or broken blade can cause uneven cuts or injury.
- Temperature Awareness:
Be cautious when working with heated equipment, such as warm plates used for melting
paraffin. Ensure that the temperature is appropriate to avoid burns or accidents.
- Proper Disposal of Waste:
Dispose of trimmed paraffin, resin, and any other waste materials properly, following laboratory
protocols. These materials should be discarded in designated waste containers to avoid
contamination or accidents.
- Prevent Chemical Exposure:
If any chemicals (e.g., fixatives or solvents) are involved in the trimming process, ensure they
are handled according to safety guidelines. Work with chemicals in a fume hood or
well-ventilated area to minimize exposure.
3. What are the things to observe in producing an ideal block ready for sectioning?
- Uniform Trimming
The tissue block should be trimmed uniformly to expose the tissue surface of interest without
leaving excess embedding material. Uneven trimming can result in inaccurate sections and
difficulty in obtaining consistent slices.
- Correct Tissue Orientation
Ensure that the tissue is oriented correctly within the block, with the tissue surface in the
correct plane for sectioning. This orientation is essential to achieve optimal sections, especially
if the tissue has complex structures (e.g., longitudinal or cross-sectional cuts).
- Firmness of the Block
The block should be sufficiently firm and stable for sectioning. If the block is too soft or brittle, it
can lead to tissue distortion or uneven cutting. The embedding medium (e.g., paraffin) should be
at the proper consistency—firm enough to hold the tissue securely but not so hard that it’s
difficult to slice.
- Smooth Surface
The exposed surface of the block should be smooth and flat, without cracks or bubbles. Any
imperfections in the surface can cause problems during sectioning and may result in artifacts in
the final tissue sections.
- Proper Cooling
Ensure that the block has fully cooled and solidified before beginning sectioning. If the block is
too soft or has not cooled completely, it can cause the tissue to shift or distort during cutting.
- Block Size and Shape
The block should be appropriately sized and shaped for the type of sectioning tool (e.g.,
microtome or cryostat) being used. A block that is too large or too small can be difficult to handle
or result in uneven sectioning.
- Avoiding Air Bubbles
Ensure that there are no air bubbles trapped in the block, especially around the tissue. Air
bubbles can cause problems during sectioning and result in poor-quality tissue slices.
