Fixatives
This is the most commonly used aldehyde-based fixative in histology.
What is formalin?
Fixatives act by stabilizing these macromolecules in tissue.
What are proteins?
This artifact is created by incomplete fixation and is commonly seen as dark basophilic staining along the tissue edges.
What is formalin pigment (or formalin artifact)?
The ideal thickness of a tissue specimen for optimal fixation is this.
What is 3-5 mm?
This fixative is used to demonstrate urate crystals in tissues, as it does not dissolve them.
What is absolute alcohol?
This fixative is ideal for preserving fine cellular detail and is commonly used for electron microscopy.
What is glutaraldehyde?
This term refers to the chemical process by which a fixative forms cross-links between proteins.
What is coagulation?
Mercuric chloride fixatives can cause this dark artifact, which requires iodine to remove.
What is mercury pigment?
The recommended ratio of fixative volume to tissue volume is this.
What is 15-20:1 (15 to 20 times the volume of the tissue)?
This fixative is commonly used for the preservation of blood smears and bone marrow biopsies.
What is methanol?
This fixative is a combination of picric acid, formaldehyde, and acetic acid
What is bouin’s solution?
Alcohol-based fixatives primarily work by this process, removing water from the tissue.
What is dehydration?
These streaky artifacts can occur due to poor dehydration following fixation.
What are water droplets?
This term refers to the stabilization of proteins to prevent autolysis and putrefaction.
What is fixation?
This fixative, containing potassium dichromate, is known for its ability to preserve mitochondria and myelin.
What is Zenker’s solution?
Aqueous formalin is prepared by diluting 37-40% formaldehyde with this ratio of water.
What is 1:9 (1 part formaldehyde, 9 parts water)?
This is the primary function of a fixative in tissue processing
What is to preserve tissue structure and morphology?
Autolysis is an artifact that occurs when tissues are not fixed promptly and results from this enzymatic process
What is self-digestion or autolysis?
This type of fixative binds chemically to tissues and increases the tissue’s rigidity.
What are additive fixatives?
This formalin fixative, buffered with sodium phosphate, is the most commonly used general-purpose fixative in pathology labs.
What is 10% neutral buffered formalin (NBF)?
This fixative is specifically used to demonstrate chromaffin granules in the adrenal medulla.
What is Orth’s solution?
This type of fixative does not create chemical bonds with proteins but rather coagulates them by removing water.
What are non-additive fixatives?
This fixative is prone to causing birefringent crystals that appear under polarized light, especially if the tissue is not properly washed after fixation.
What is formalin?
Fixation should be performed at this temperature to ensure optimal preservation of tissue morphology.
What is room temperature (18-22°C)?
This fixative is known for being an excellent choice for the preservation of lipids, even though most fixatives remove them.
What is osmium tetroxide?