L.4 Embedding, Microtomy, Cryotomy Flashcards
What is embedding in histology?
Embedding is the process of surrounding processed tissue in a solid medium, usually paraffin wax, to form a stable block for microtomy.
What is the primary goal of embedding?
The goal is to preserve orientation and enable thin sectioning for microscopic examination.
What is the first step in the embedding process?
Prepare Tissue.
What should be assessed when preparing tissue for embedding?
Tissue size, type, and required orientation.
What is the second step in the embedding process?
Embed the Tissue.
What is the purpose of using a mold in the embedding process?
To provide a shape and support for the tissue when surrounded by wax.
Fill in the blank: During embedding, you must use _______ to position the tissue in the wax.
forceps
What is the importance of orientation and positioning in embedding?
Ensures diagnostic features e.g. epithelium, margins are sectioned properly.
Why is flatness important during the embedding process?
Tissue must lie flat for clean, even sectioning.
What should be done if multiple tissues are embedded together?
All should be positioned flat, which can be challenging.
What does surrounding wax provide during sectioning?
Stability for sectioning.
What is a key quality control check during embedding?
Check for fixation or processing issues—soft tissue may need reprocessing.
What should be verified in quality control checks?
Correct number of pieces matches worksheet.
What is necessary to ensure stable block mounting?
Trim excess wax.
What is the purpose of microtomy?
To obtain thin sections (3–5 μm) for microscopy, allowing visualization of tissue at the cellular level.
What is the most common type of microtome?
Rotary microtome (manual, semi-, or fully-automated).
What type of blades does a rotary microtome use?
Disposable steel blades for wax sections.
What are the main parts of a microtome?
- Chuck (holds the block)
- Blade & blade holder
- Advance/retract mechanism
- Rotary handle
What is the first step in the sectioning process?
Lock blade and insert cooled block into chuck.
What should be done after inserting the block into the chuck?
Retract chuck until block is behind the blade.
What is the purpose of advancing the block toward the blade in small increments?
To cut desired section thickness using rotary motion (usually 3–5 μm).
What should be done to improve the quality of sections?
- Cool blocks beforehand
- Trim carefully to expose tissue face
- Cut single sections, serials, or levels depending on analysis
What is a special consideration for lymph nodes and renal biopsies?
Use a thickness of 2–3 μm.
What thickness is recommended for brain tissue to ensure nerve visibility?
10–15 μm.
