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Cellular Pathology I > Minerals and Pigments > Flashcards

Minerals and Pigments Flashcards

1
Q

What is a pigment?

A

A coloured opaque substance present in cells or tissues

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2
Q

List the three main forms of pigment.

A

Artefact

Endogenous

Exogenous

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3
Q

Artefact pigments are mostly due to __________ _________.

A

Chemical fixation

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4
Q

True or false: formalin may leave brown artefact pigment.

A

True

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5
Q

What is an endogenous pigment?

A

Pigments formed in the body, and can be distinguished as hematogenous pigments such as bile, and non-haematogenic pigments such as melanin, or lipofuschin

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6
Q

Endogenous pigments are formed within the cell where they have a physiological role or are by-products of _______________.

A

Metabolism

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7
Q

____________ are observed as yellow-brown intracellular granules inside cells.

A

Haemosiderins

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8
Q

What stain is used to demonstrate haemosiderins?

A

Perl’s Prussian Blue

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9
Q

List one condition in which excessive haemosiderins may be observed.

A

Haemochromatosis

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10
Q

After ageing red cells are broken down by the reticuloendothelial system, the iron is removed from haemoglobin and the result is the formation of ____________.

A

Biliverdin

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11
Q

Biliverdin is converted to ______ in liver and is stored as bile within the gallbladder.

A

Bilirubin

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12
Q

‘_______ __________’ refers to bilirubin, biliverdin and haematoidin.

A

Bile pigment

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13
Q

List two scenarios in which an excess of bile pigments may be found.

A

Bile duct obstruction

Abnormality of bilirubin biliverdin metabolism

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14
Q

With H&E stain, bile pigments appear as __________-_______ ___________.

A

Yellow-brown crystals

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15
Q

Bile pigments are identified using the ________ reaction.

A

Fouchet

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16
Q

State the principle of the Fouchet reaction.

A

Ferric chloride oxidises all bile pigments to green biliverdin.T his oxidation reaction is rapidly accomplished by ferric chloride in trichloroacetic acid medium (Fouchet’s reagent). Biliverdin is then stained emerald green by acid fuchsin in van Gieson solution.

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17
Q

List two non-haematological pigments.

A

Lipidic, such as lipofucsin, and non-lipidic, such as melanin

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18
Q

________ is a wear-and-tear pigment.

A

Lipofucsin

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19
Q

_________ ______________ is excessive storage of lipofucsin.

A

Ceroid lipofuscinosis

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20
Q

What is melanin?

A

A pigment produced through a multistage chemical process known as melanogenesis, where the oxidation of the amino acid tyrosine is followed by polymerization

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21
Q

Melanin pigments are produced in a specialized group of cells known as ______________.

A

Melanocytes

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22
Q

Melanin is normally found in the ______.

A

Skin

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23
Q

____________ DOPA is an intermediary pigment of melanin.

A

Tyrosine

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24
Q

Melanin is produced by melanocytes in the epidermis and in skin phagocytes called ‘melanophages’ during ______________.

A

Inflammation

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25
Q

Melanin production is observed in the _________ ______, the iris, and also in melanomas of the eye.

A

Ciliary body

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26
Q

Melanin production is ound in the substantia niagra of the ________, with reduced amounts in Parkinson’s disease.

A

Brain

27
Q

Define ‘melanoma’.

A

Abnormal growth of skin cells, which most often develops on skin exposed to the sun

28
Q

List three forms of skin cancer.

A

Basal cell carcinoma
Squamous cell carcinoma
Melanoma

29
Q

Sometimes, melanoma develop from a _______ with concerning changes including an increase in size, irregular edges, change in colour, itchiness, or skin breakdown.

A

Mole

30
Q

The primary cause of melanoma is __________ ______ exposure in those with low levels of skin pigment.

A

Ultraviolet light

31
Q

Name a genetic defect which increases the risk of developing melanoma.

A

Xeroderma pigmentosum

32
Q

How is melanoma diagnosed?

A

Skin biopsy of the subject lesion

33
Q

True or false: melanoma is the least concerning form of skin cancer.

A

False

34
Q

Describe the Argentaffin reaction.

A

Granules with melanin bind and reduce silver ions via Masson Fontana stain, and
granules reduce ferric ferricyanide via Schmorl’s stain

35
Q

Melanoma can be bleached with ____________ ________________

A

Potassium permanganate

36
Q

State one monoclonal antibody which can be used in visualising melanoma.

A

S100

37
Q

What is HMB45?

A

An antigen on melanosomes

38
Q

List two other methods of melanoma histochemistry visualisation.

A

Enzyme methods, such as DOPA reaction

Fluorescent methods

39
Q

State the principle of Schmorl’s reaction.

A

Melanin will reduce ferricyanide to ferrocyanide with the production of Prussian blue, in the presence of ferric salts

40
Q

Cells that are capable of producing melanin can be demonstrated by the __________________ (DOPA) method.

A

Dihydroxyphenylalanine

41
Q

The enzyme __________, localized within cells, will oxidise DOPA to form an insoluble brown black pigment.

A

Tyrosinase

42
Q

Melanins are insoluble in most ________ solvents due to tight bonding with proteins.

A

Organic

43
Q

What is vitiligo?

A

An acquired pigmentary disorder of the skin and mucous membranes

44
Q

____________ is characterized by depigmented macules and patches.

A

Vitiligo

45
Q

Superficial perivascular and perifollicular lymphocytic ____________ may be observed at the margin of vitiliginous lesions.

A

Infiltrates

46
Q

True or false: vitiligo is frequently associated with disorders of autoimmune origin, with thyroid abnormalities being the most common.

A

True

47
Q

_______ amounts of copper are found normally in some tissues.

A

Small

48
Q

Where are increased copper deposits found in Wilson’s disease?

A

Brain, liver, and eyes

49
Q

Liver staining for copper with ________ ____ shows red brown granules in hepatocytes.

A

Rubeanic acid

50
Q

What causes Wilson’s disease?

A

A mutation in the Wilson disease protein (ATP7B) gene

51
Q

The ATP7B protein transports excess copper into ______, where it is excreted in waste products.

A

Bile

52
Q

Normal stores of _______ are found in bone marrow, liver, and spleen.

A

Iron

53
Q

Abnormal deposits of ___________ can be associated with atherosclerosis, sarcoid, necrotic tissues in TB infection, some tumours, and in joints in chondrocalcinosis.

A

Calcium

54
Q

What is the von Kossa method?

A

An indirect way of detecting calcium, where silver nitrate replaces the carbonate anions of calcium salts (silver substitution method). Sunlight reduces the silver salt to visible metallic silver, and unreduced silver is removed by sodium thiosulphate

55
Q

What colour do calcium deposits appear as?

A

Black

56
Q

__________ is commonly inhaled, ingested or implanted in skin following industrial exposure.

A

Carbon

57
Q

How can melanin be distinguished from carbon?

A

Melanin’s colour will disappear with bleaching, but carbon’s colour will remain

58
Q

Asbestos fibres are ____________ fibres of magnesium silicate.

A

Birefringent

59
Q

Where do asbestos fibres collect?

A

In alveoli at periphery of lung

60
Q

Asbestos fibres have a ___________ ______, which contains haemosiderin.

A

Proteinaceous coat

61
Q

____________ pigments are found in the skin and adjacent lymph nodes of various colours of the dye pigments seen.

A

Tattoo

62
Q

Lugol’s iodine, picric-alcohol, and potassium permanganate bleach are reagents used to __________ pigments.

A

Remove

63
Q

What stain is used to demonstrate asbestos fibres?

A

Perl’s Prussian Blue

Cellular Pathology I (9 decks)

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