- What are pigments in histopathology?
- Why lipofuscin is called the wear and tear pigment?
- What are the types of fixative?
- What are the types of fixation?
- What are exogenous pigments?
- What are endogenous pigments?
- What is fixation pigment?
- How Hemosiderin is formed?
- What different types of pigments are commonly seen in histology?
- What is the fixative?
- Is melanin an endogenous pigment?
- What is lipofuscin pigment?
What are pigments in histopathology?
The first group consists of those pigments which are normal constituents of or are derived from blood.
Hemoglobin, hemosiderin and hematoidin are included in this group and are endogenous.
The second group consists of the acid hematins, such as formalin pigment and malaria pigment, which are artifact pigments..
Why lipofuscin is called the wear and tear pigment?
Lipofuscin is sometimes called “wear-and-tear pigment”, since the amount increases over time (i.e., with advancing age) in cells like hepatocytes and neurons which are both permanent (not routinely replenished) and metabolically active. … Each of these cell types has a characteristic position.
What are the types of fixative?
Popular fixative solutionsPhosphate buffered formalin.Formal calcium.Formal saline.Zinc formalin (unbuffered)Zenker’s fixative.Helly’s fixative.B-5 fixative.Bouin’s solution.More items…
What are the types of fixation?
Chemical fixationCrosslinking fixatives – aldehydes.Precipitating fixatives – alcohols.Oxidizing agents.Mercurials.Picrates.HOPE fixative.Acidity or basicity.Osmolarity.More items…
What are exogenous pigments?
Exogenous pigments are characterized as agents containing color that are formed outside of the body but found within tissues. Exogenous pigments can find their way into the body in a variety of ways. Examples of exogenous pigments are carbon, asbestos fibers, tattoo ink, and metals.
What are endogenous pigments?
Endogenous pigments are characterized as hematogenous and nonhematogenous. Hematogenous pigments originate from blood and nonhematogenous pigments originate from non-blood, fat or fatlike, and non-fatlike substances. Examples of endogenous hematogenous pigments found in the liver are hemosiderin and bilirubin.
What is fixation pigment?
Formalin pigment is a brown, granular, doubly refractile deposit seen both intracellularly and extracellularly in tissues which have been fixed with a simple formalin solution, such as formal-saline. … Formalin pigment may be easily stopped from forming by using 10% neutral buffered formalin (NBF) as the fixative.
How Hemosiderin is formed?
Hemosiderin often forms after bleeding (haemorrhage). When blood leaves a ruptured blood vessel, the red blood cell dies, and the hemoglobin of the cell is released into the extracellular space.
What different types of pigments are commonly seen in histology?
Other pigments encountered in histological sections are hematoidin (Bright yellow), hemosiderin (light brown), melanin (dark brown) among others.
What is the fixative?
A fixative is a stabilizing or preservative agent: Dye fixatives or mordants, are chemical substances used in processing fabrics to create circumstances in the micro-substrates causing dye molecules to adhere and remain that way.
Is melanin an endogenous pigment?
Endogenous pigments are pigments present and produced in body under normal conditions. In mammals, four groups of endogenous pigments are present. These groups are melanin, lipofuscin, hemosiderin and bilirubin.
What is lipofuscin pigment?
Lipofuscin is a fluorescent pigment that accumulates with age in the lysosomal compartment of postmitotic cells in several tissues, such as neurons and heart and skeletal muscle among many others. … RPE lipofuscin can act as a photosensitizer, generating reactive oxygen species, and mediating light-induced damage.