Lecture 2: Tissue Preparation Flashcards
What is histology?
- The study of the microscopic structure of biological matter.
- An extension of anatomy “microscopic anatomy”
- Histopathology is the study of pathological cells and tissues.
- Histology is essential for understanding pathology and disease diagnosis.
-Diagnostic histopathology is a relatively slow process and does not normally produce instantly.
What does a histopathology report produce?
What is the process of tissue preparation in histology?
- Fixation
- Dissection
3 Processing - Embedding (Blocking out)
- Microtomy
- Staining
Then to microscopy
What is fixation in tissue preparation?
- Involves terminating cell metabolism
- Prevents enzymatic degradation of cells and tissues by autolysis.
- Kills pathogenic micro-organisms, such as bacteria, fungi, viruses.
High quality preservation is key in most histopathology tests. As poorly fixed specimens can affect diagnosis or not yield enough information.
Can be achieved through either chemical or physical methods (heating and freezing).
What qualities would a perfect chemical fixative have?
What branches of fixatives are there?
- Cross-linking: binds amino acids with proteins to adjust their three-dimensional structure, preventing autolysis and putrefaction)
- Precipitating: removes water from cellular matrix, which disrupts the three-dimensional protein structure, thereby precipitating the protein (acetic acid coagulates nucleic acids)
- Compound: A mixture of both cross-linking and precipitating.
What is formaldehyde?
What reactions are involved in formaldehyde fixation.
What are the fixation properties of formaldehyde?
What is glutaraldehyde?
- Glutaraldehyde reacts faster than formaldehyde.
- Binds up to
How are alcohols used in fixation?
What factors affect the rate of fixation?
What are the two methods of physical fixation?
Heating and freezing.
What substances are used in freezing physical fixation?
SPECIMEN DISSECTION/GROSSING
