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What are pigments that come from outside the body called?
Which of the following is NOT considered an endogenous pigment?
What is the common effect of increased melanin pigmentation?
What condition is characterized by a loss of pigment-producing melanocytes?
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Hemosiderin is primarily derived from which component?
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Which pigment acts as a protective screen against ultraviolet radiation?
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What pathological condition is characterized by the accumulation of carbon in the lungs?
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Which of the following is a potential cause for decreased pigmentation in the skin?
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What forms when there is a local or systemic excess of iron?
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What distinguishes hemosiderin from ferritin?
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Which condition involves hemosiderin accumulation without tissue damage?
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What is hemosiderin primarily identified by?
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In which organ are hemosiderin granules typically found?
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What type of pigment is lipofuscin described as?
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What can lead to hemichromatosis?
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What condition is primarily seen with extensive hemosiderin accumulation in parenchymal cells?
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What are lipofuscin granules primarily characterized by?
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Which type of calcification occurs in dead or degenerated tissues with normal calcium metabolism?
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Which condition is associated with high serum calcium levels?
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Which of the following is NOT a cause of metastatic calcification?
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What type of pathological calcification is commonly seen in atherosclerosis?
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Which staining method is used for detecting calcium deposits microscopically?
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What is the appearance of calcification under microscopy?
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What is a primary characteristic of metastatic calcification?
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Study Notes
Pigments
- Pigments are colored substances, either exogenous (from outside) or endogenous (synthesized within the body).
- Examples of exogenous pigments include carbon (coal dust), which can be inhaled and lead to Anthracosis (accumulation of carbon in the lungs).
- Examples of endogenous pigments include melanin, bilirubin, hemosiderin, and lipofuscin.
Melanin
- Melanin is a brownish-black pigment produced by melanocytes in the epidermis.
- Acts as a screen against harmful UV radiation.
- Increased melanin pigmentation can occur due to sun tanning or diseases like nevus or malignant melanoma.
- Decreased melanin pigmentation is seen in conditions like vitiligo (loss of melanocytes) and albinism (melanocytes present but lack tyrosinase enzyme).
Hemosiderin
- Golden yellow-to-brown, granular pigment derived from hemoglobin.
- One of the major storage forms of iron.
- Iron is normally transported by transferrins and stored as ferritin micelles.
- Hemosiderin granules represent aggregates of ferritin micelles.
- Identified by its blue staining reaction with Prussian blue dye.
- Accumulates in tissues due to local or systemic iron excess, leading to hemosiderosis (within macrophages) or hemochromatosis (within parenchymal cells, causing tissue damage).
Lipofuscin
- Known as "wear and tear" pigment, it's an insoluble brownish-yellow granular intracellular material.
- Consists of lipids and phospholipids complexed with protein.
- Derived from free radical-catalyzed peroxidation of polyunsaturated lipids in subcellular membranes.
- Not harmful to the cell but acts as a marker of past free radical injury.
- Seen in tissues like the heart, liver, and brain as a function of age or atrophy.
- Can impart a brown appearance to tissue, known as brown atrophy.
Pathological Calcification
- Abnormal deposition of calcium salts, along with other minerals, in tissues.
- Two forms: Dystrophic and Metastatic calcification.
Dystrophic Calcification
- Deposition of calcium salts in dead or degenerated tissues.
- Occurs with normal calcium metabolism and serum calcium levels.
- Seen in atherosclerosis, damaged heart valves, and necrosis.
Metastatic Calcification
- Deposition of calcium salts in vital tissues, reflecting abnormal calcium metabolism and high serum calcium (hypercalcemia).
- Often a consequence of parathyroid hormone excess.
- May occur in normal tissues, including blood vessels, stomach, kidneys, and lungs.
Metastatic Calcification: Principle Causes
- Hyperparathyroidism due to parathyroid tumors.
- Bone tissue destruction from bone marrow tumors like multiple myeloma.
- Vitamin D-realted disorders like Vitamin D intoxication and sarcoidosis.
- Renal failure causing secondary hyperparathyroidism.
General Morphology of Pathologic Calcification
- Grossly: Appear as fine white granules or clumps, gritty deposits.
- Microscopically: Appear as intracellular and/or extracellular deeply basophilic, irregular, granular clumps.
- Special stains for calcium: von Kossa (black) and Alizarin red S (red).
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Description
This quiz explores various types of pigments, both exogenous and endogenous, highlighting their functions and biological significance. Learn about melanin and hemosiderin, their roles in the body, and conditions related to pigmentation. Test your understanding of these essential substances!
