Week 4 Flashcards
Histology steps
SFDPSM
Specimen reception
Fixation
Disection
Processing
Staining
Microscopic examination
Importance of staining
Highlights specific structures and helps to differentiate
Goal of staining nucleus
To locate the cell
What is the most commonly used stain in histology?
Hematoxylin and Eosin (H&E) stain.
What does hematoxylin stain, and what color does it produce?
Hematoxylin stains nuclei blue/purple by binding to acidic structures (DNA, RNA).
What does eosin stain, and what color does it produce?
Eosin stains cytoplasm, extracellular matrix, and muscle fibers pink by binding to basic structures (proteins).
Uses ionic bonding
What is the purpose of PAS (Periodic Acid-Schiff) staining?
PAS stains carbohydrates, glycogen, and mucins a bright magenta color
What is the purpose of Gram staining in histology?
It differentiates Gram-positive bacteria (purple) from Gram-negative bacteria (pink).
What is Ziehl-Neelsen staining used for?
Detecting acid-fast bacteria, such as Mycobacterium tuberculosis, which appear bright red against a blue background.
What stain is used to detect Helicobacter pylori in gastric biopsies?
Giemsa stain or Warthin-Starry silver stain.
What is immunohistochemistry (IHC) used for?
Identifying specific proteins and antigens in tissue sections using labeled antibodies.
Artefact
an artificial structure
or tissue alteration on a prepared microscopic slide
as a result of an extraneous factor.
ALK stands for
Anoplastic lymphena kinase
What stain is used to detect bilirubin in liver tissue?
Halls stain
What is Ki-67 staining used for?
Cell proliferation
Neutral dye example and colour
Giemsa stain (blue)
Congo red dye uses
H bonds
Name all mutation types
Missense – change in DNA base
➢ Nonsense – change in DNA sequence
➢ Deletions – deletion of a base
➢ Insertions – Addition of a base
➢ Duplications – Repetition of a DNA segment
➢ Trinucleotide repeats – Multiple DNA repeats
What is the main reason for staining tissues in histology?
To enhance contrast and detail under the microscope, making cells and tissues distinguishable.
What are the basic components targeted by stains?
Nucleus
Cytoplasm
What are the classifications of dyes?
BHAENG
Basic (e.g. haematoxylin)
Acidic (e.g. eosin)
Neutral (e.g. Giemsa)
What do basic dyes stain?
They stain acidic structures (like nucleic acids)
What do acidic dyes stain?
They stain basic structures (like cytoplasm,
What is a ‘mordant’?
A chemical that helps fix the dye to the tissue, often forming a “dye lake”
