Histopathology is the microscopic examination of tissue to study disease. Before a pathologist can interpret a tissue sample, it must be collected, preserved, prepared, and placed on a slide. This lesson follows that process from specimen collection to microscope-ready sections.
Tissue for histopathological examination may come from surgery, a biopsy, or an autopsy. After removal, it may be dissected while fresh by an expert, then placed in a fixative. Fixation stabilizes tissue and helps prevent decay so that its structure can be examined later.
All flashcards
What does histopathology examine?
It examines tissue microscopically to study disease. Pathologists commonly examine processed tissue sections on slides.
What is the purpose of fixation?
Fixation stabilizes collected tissue and helps prevent decay, preserving structures for later processing and microscopic examination.
What happens during grossing?
For a large specimen, the pathologist examines it and selects and trims areas likely to provide useful diagnostic information.
Why are alcohol and xylene used during routine processing?
Increasing alcohol concentrations remove water from tissue. Xylene replaces alcohol because embedding wax is soluble in xylene and can then infiltrate the specimen.
What is a cryostat, and when is it used?
A cryostat is a refrigerated device containing a microtome. It cuts thin frozen tissue sections, often for rapid assessment during surgery.
Quiz questions
In an H&E stain, what does eosin typically color?Answer: Cytoplasm and extracellular connective-tissue matrix
What does the Perls' Prussian blue reaction demonstrate in tissue?Answer: Iron deposits
What does immunohistochemistry use to highlight specific tissue targets?Answer: Antibodies that bind selected molecules
Which molecules can in situ hybridization identify within tissue?Answer: Specific DNA or RNA molecules
What does a clear surgical margin mean in a cancer resection report?Answer: No tumor is identified at the examined cut edge.
Based on the Wikipedia article Histopathology, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.