[C] 1.35 Pathologic pigmentation caused by melanin, lipofuscin, and ceroid Flashcards Preview

Pathology A - General Pathology > [C] 1.35 Pathologic pigmentation caused by melanin, lipofuscin, and ceroid > Flashcards

Flashcards in [C] 1.35 Pathologic pigmentation caused by melanin, lipofuscin, and ceroid Deck (25)
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1
Q

Melanin, lipofuscin and ceroid are grouped as…

A

Autochton pigments

Anhaemoglobinogenous pigments

2
Q

Melanin: Chemistry

A
  • Insoluble in water, acids and fat solvents
  • Soluble in K-OH, Na-OH & H2O2 (Bleach)
3
Q

Melanin is produced by

A

Ectodermal origin cells:

  • Synthesis initiation by tyrosinase enzymes
  • MSH stimulates production of:
    • Melanin
    • Brown-black pigment (no iron)
4
Q

Give the order of melanocyte production of melanin granules

A
  1. Premelanosoma
  2. Melanosoma I
  3. Melanosoma II
  4. Melanin granule

Enzyme: Tyrosinase

5
Q

Where is melanin stored?

A

Melanophages

6
Q

Reaction of formin melanin

A

Tyrosin → Melanin

  • Tyrosinase enzyme (oxidation)
  • Stimulation by the hypophysis (MSH & ACTH)
7
Q

Where in the body is melanin located (physiologically)

A
  • Skin
    • Epidermis & corium
  • During prengnancy
    • Nipples, face, mid-line of belly
  • Eye
  • Ganglion cells
  • Leptomenings
  • Oral cavity
  • Mammary gland - Berkshire pigs
  • Serous membrane - Reptiles & birds
8
Q

Give the three variations of abnormal pigmentation

A
  1. Hyperpigmentatio
  2. Hypopigmentatio
  3. Albinismus
9
Q

Hyperpigmentatio

A
  • Radiation & arsenic treatment
  • Naevi (naevus pigmentosus) (birth mark)
  • Focal melanosis
  • Melanoma
  • Acanthosis nigricans
  • Addision’s disease
10
Q

Hypopigmentatio

A
  • Leukoderma (surgical treatment)
  • Vitiligo (pigment free area)
11
Q

Acanthosis nigricans

A
  • Unknown origin
  • Hyperpigmentation of axilla, thorax, inguinal or circum-anal region
  • Uneven proliferation of epithelial cells in stratum spinosum
  • Thickened skin with uneven surface
  • Velvet touch
12
Q

Hypopigmentation

A
  • Age
  • Vitiligo (hamartia) (Depigmentation of skin)
  • Leukoderma (Focal absence after injury)
  • Trophoneurotic problems
    • Dourine in horses
    • Depigmented areas
  • Pale areas after maceration
  • Albinism
    • Pathological absence of melanin
    • Congenital in rodents
13
Q

Lipofuscin

A

Golden-brown pigment - Proteins & lipids, no iron

  • Formed in lysosomes of ageing cells
14
Q

Lipofuscin production

A

Autooxidation of unsaturated lipids

  • All three germ layers may contain insoluble in water, acid & alkali
15
Q

Lipofuscin: Location

A
  • Liver
  • Kidney tubule
  • Adrenal gland
  • Choroid plexus
  • Muscle cells
16
Q

Observations of lipofuscin under the electron microscope

A
  • Dense
  • Amorphous autophagosomes
  • Granules
  • Lipids
17
Q

Lipofuscin: Pathogenic conditions

A
  • Brown bowel syndrome
  • Neuronal ceroid lipofuscinosis
18
Q

Brown bowel syndrome

A
  • Dogs
  • Diarrhoeal diseases
  • Steatorrhea (High fat excretion)
  • Pancreatic acinar deficiency
  • Malabsorption
  • Intestine: Brown
    • Smooth muscle cells
19
Q

Neuronal ceroid lipofuscinosis

A

English setter, cattle, sheep, cat

  • IC accumulation
  • The progressive loss of cells in the brain and the cerebral function
20
Q

Ceroid

A
  • Lipogenous pigment
  • Partially oxidised & polymerised unsaturated fatty acid bound to proteins
  • Produced in macrophages and hepatocytes
  • Ziehl-Neelsen positive

Yellow fat disease

21
Q

Yellow fat disease

A

Alcohol soluble - icterus

22
Q

Ceroid-like pigment

A

Yellow appearance

  • Lipocytes
  • Macrophages
  • MPS-cells
  • Yellow adipose
    • Yellow fat disease
    • Caused by high unsaturated FA in feed
23
Q

Ochronosis

A

(Alkaptonuria)

  • Inherited disturbance of the protein metabolism
  • Aa → Homogentisic-acid
  • Oxidation → Coloured substance
24
Q

Ochronosis signs

A

Cartilage, tendons & ligaments become greenish

Bones don’t become discoloured

25
Q
A

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