Pigments Flashcards

1
Q

Pigments are coloured substances, some of which accumulate in the cell under special circumstances.

● They could be:
○ Normal e.g. ______ or abnormal e.g. ____

A

melanin; tatoo

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2
Q

________ is the most common exogenous
pigment.

A

Carbon (Coal dust)

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3
Q

Carbon(coal dust)

  • is inhaled daily as an ______
    • When inhaled, it is ingested by the _______ in the ____ which transport them via _______ to the regional _____
A

air pollutant

macrophages; alveoli

lymphatic channels

lymph nodes

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4
Q

Carbon dust is ubiquitous

T/F

A

T

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5
Q

Coal dust

This pigments forms the ___ coloured patches seen on the _____ surface of the lungs and ______ in the ________

A

dark; pleural; lymph nodes; tracheobronchial tree.

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6
Q

Coal worker’s pneumoconiosis is a disease condition where there is a ______ reaction to the large amounts of coal dust inhaled by workers in this
profession.

A

fibroblastic

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7
Q

Endogenous:
•______ (wear and tear
pigment)
• Hemosiderin
•___________ – deposited in the connective tissues, skin in patients with alkaptonuria. The pigmentation is known as _______.
• Melanin
• Bilirubin

A

Lipofuscin

Homogentisic acid

ochronosis

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8
Q

Lipofuscin

• Granules composed of _______ complexes.
● Found in _______ diseases and are the end products of oxygen radical mediated membrane damage which are not eliminated by intracellular ______

● They subsequently persist in the ______ as collections of _______.

A

lipid-protein

ageing or debilitating

lipid peroxidation.

Lysosomes; indigestible material

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9
Q

Lipofuscin is injurious to the cell

T/F

A

F

Not injurious to the cell

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10
Q

Lipofuscin has no gross features

T/F

A

T

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11
Q

Melanin

• ______ pigment.
● Normally seen in the skin, hair etc
● Synthesized in the _____ and _____ cells by the action of _____ on ______ to form
__________(DHPA).

A

Brown-black

melanocytes; dendritic

tyrosinase on tyrosine

dihydroxyphenylalanine

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12
Q

Melanin is derived from hemoglobin

T/F

A

F

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13
Q

Melanin

Disorders of melanin pigmentation can cause generalised and localised _______/_______

A

hyperpigmentation/hypopigmentation

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14
Q

Generalised hypopigmentation (Albinism)

● Genetic defect in ______
●_______ cases have almost no pigment in the skin and hair and complain of severe ________.
● Chronic sun exposure may lead to ______

A

tyrosinase

Oculocutaneous; photophobia

skin cancer

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15
Q

Focal hypopigmentation
●_________: localised loss of skin pigmentation.

●_____: More common

● Acquired focal hypopigmentation: healing of wounds,_______,_____ etc.

A

Leucoderma

Vitiligo

leprosy, lupus

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16
Q

Alkaptonuria

● Autosomal (dominant or recessive?) disorder
● Deficiency of ____ enzyme which is required to break down ________ which therefore accumulates in the tissues
and is excreted in the urine.
● Urine turns ____ if allowed to stand for a few hours in the air ( ______ of _______).

A

Recessive

oxidase

homogentisic acid.

black

oxidation of homogentisic acid

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17
Q

black pigment in alkaptoneuria is called ______ and is deposited _____cellularly. E.g. Joints, ligaments, skin
tissue.

A

ochronosis

both inter and intra

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18
Q

● Iron in tissues can be stored either as
○________
○________

A

Ferettin

Haemosiderin

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19
Q

● Iron in tissues can be stored either as
○ Ferettin (Fe complexed to ______)
○ Haemosiderin (formed by _______)

A

Apoferritin

aggregates of ferritin

20
Q

● Excessive storage of haemosiderin occurs when there is increased ______ or ________ overload.

A

Breakdown of red blood cells

systemic iron

21
Q

Hemosiderin can only be localized

T/F

A

F

Can be localised or generalised

22
Q

Bilirubin
● Pigment derived from _____, found in bile.
● Excess bilirubin (hyperbilirubinaemia) causes ______
● Aetiology
○ Increased production (excessive _______)
○ Defective conjugation (_____ disease/injury)
○ Defective transport (_________ ducts)

A

haemoglobin

jaundice

RBC destruction

liver

intra/extrahepatic bile

23
Q

Bilirubin is iron-containing

T/F

A

F

is non-iron containing

24
Q

Bilirubin Accumulates as _____ pigment in the fluids and tissues of the body e.g. hepatocytes, skin, sclera.

● In infants, high levels of unconjugated bilirubin may cause ______ injury (________)

A

yellow

brain

kernicterus

25
Q

Excessive absorption of iron
● Excessive absorption even with normal intake is known as _______ or ______
● It is an autosomal (dominant or recessive?) disease

A

idiopathic or hereditary haemochromatosis.

Recessive

26
Q

Excessive absorption of iron

Characterised by:
○ Pigmented ______
○____ pigmentation
○ _______ damage resulting in diabetes (‘______ diabetes’)

A

liver cirrhosis

Skin

Pancreatic; bronze

27
Q

Excessive iron intake
● First observed in the ____ tribe of _____ due to Consumption of alcohol brewed in _____ vessels.
● Later found in other communities without similar history.
● A gene called _____ has been identified as the predisposing factor to this overload.

A

Bantu; South Africa

ungalvanised iron

ferroportin

28
Q

Histology of excessive iron intake
● Intracytoplasmic coarse, _______, granular pigment
● Visualised with _______/______ stain

A

golden-brown

Prussian blue/Perl’s

29
Q

Localised Haemosiderosis
● When there is haemorrhage into the tissue, the red blood cells are ___ releasing their _____ which is then taken up by _____, degraded and stored as ______. Examples are
○ Haemosiderin laden macrophages at sites of ________
○ Haemosiderin laden alveolar macrophages (______ cells) in the ___ in ______ failure

A

Lysed; haemoglobin; macrophages; haemosiderin

endometriotic deposits

heart failure

lungs; left ventricular

30
Q

______ is the ageing pigment

A

Lipofuscin

31
Q

Lipofuscin pigment appears as ______ in tissue segments

A

Yellow brown

32
Q

Lipofuscin is seen in cells undergoing (slow or rapid?) , (regressive or progressive?) changes and is particularly prominent in the _______ and _____ of ageing patients

A

Slow
Regressive

Liver and heart

33
Q

_____/______ is used to stain for iron

A

Perls stain/ Prussian blue

34
Q

Lipofuscin is to _____ brown as haemosiderin is to _______ brown

A

Yellow

Golden yellow

35
Q

Tattoo pigments are also absorbed by ________

A

dermal macrophages.

36
Q

In anthracosis, the macrophages which ingest the inhaled carbon particles, also elaborate ______ which encourage the formation of _____ in the lungs. This may
result in difficulty in respiration.

A

cytokines

fibrosis

37
Q

Generalised hyperpigmentation
●________ disease: hyperpigmentation of sun exposed areas
●________: seen in pregnancy/oral contraceptive pills.
•________ induced hyperpigmentation of the face, nipples,
genitalia.
● Chronic _____ poisoining: classic raindrop pigmentation of
the skin.

A

Addison’s

Chloasma

Oestrogen

arsenic

38
Q

Focal hyperpigmentation
● Neurofibromatosis:________ spots
● Peutz-Jeghers syndrome:_______
● Melanosis coli: _________
● Melanotic tumours: _____
● Lentigo:___
● Dermatopathic lymphadenopathy: Lymph nodes draining _______

A

Cafe-au-lait ; Peri-oral

mucosa of the colon; skin

skin

skin lesions

39
Q

Leucoderma is an autoimmune condition

T/F

A

T

40
Q

Vitiligo may be familial which means???

A

Other members of the family may have it

41
Q

Homogentisic acid is converted to _______ by homogentisic acid oxidase

A

Maleylacetoacetic acid

42
Q

Localised Haemosiderosis
● When there is haemorrhage into the tissue, the red blood cells are lysed releasing their haemoglobin which is then taken up by macrophages, degraded and stored as
haemosiderin.

Examples are
○ Haemosiderin laden macrophages at sites of _________
○ Haemosiderin laden ____ macrophages (_____ failure
cells) in the _____ in ______ failure

A

endometriotic deposits

alveolar; heart; lungs

left ventricular

43
Q

Generalised haemosiderosis

Causes are broadly categorised into:
● Increased breakdown of haemoglobin e.g.____________ anaemia, excessive _______
● Excessive _________ of iron
● Excessive iron _____ e.g. ______, ____ brewed in certain vessels.

A

chronic hemolytic; blood transfusion

intestinal absorption

intake; multivitamins

alcohol

44
Q

Excessive absorption even with normal intake is known as _________________

A

idiopathic or hereditary haemochromatosis.

45
Q

idiopathic or hereditary haemochromatosis

It is an autosomal (recessive or dominant?) disease

● Characterised by:
○ Pigmented liver _____
○________
○ ______ damage resulting in diabetes (‘_______ diabetes’)

A

Recessive

cirrhosis

Skin pigmentation

Pancreatic

bronze