Page 17 - Headlines Histology2024_Neat

Hemosiderin and bilirubin

• They are formed as the result of degradation of old erythrocytes by the
spleen macrophages.

• Hemoglobin is degraded into hemosiderin and bilirubin.
• The hemosiderin is a golden brown iron-containing pigment usually seen

within the cytoplasm of the splenic macrophages.
• The bilirubin is yellowish-brown pigment. It has to be removed from the

blood stream by the liver and excreted in bile.
Melanin

• The melanin is a brown-to-black pigment presents in skin, hair and eyes.
There is two type of melanin: eumelanin, which has a brownish black color,
and phaeo

• melanin that has a reddish-yellow color.
Lipofuscin
• The lipofuscin is a golden-brown intracellular pigment represents a normal

product of organelle's degradation.
• It accumulates with increasing age particularly in long-lived cells such as

neurons and cardiac muscle cells (hence, they are referred to as age
pigments or wear and tear pigments).
Crystals

• Such as calcium oxalate and calcium carbonate crystals can be seen in the
cytoplasm during certain disease conditions.

NUCLEUS

• The nucleus is the archive of the cell that carries the genetic information
necessary to regulate the different cell functions.

• It consists primarily of DNA (20% of its mass), DNA-binding proteins, and
some RNA.

• The DNA-binding proteins are of two major type histones and non-histones.

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