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SP1 General Pathology > Lecture 19/20 4/11/24 > Flashcards

Lecture 19/20 4/11/24 Flashcards

1
Q

What are exogenous pigments?

A

pigments formed outside the body

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2
Q

What are the characteristics of anthracosis?

A

-due to inhalation of carbon
-indicates inhalation of polluted air
-asymptomatic

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3
Q

What are the gross lesions associated with anthracosis?

A

-tiny gray-black specks throughout lung
-gray-black tracheobronchial lymph nodes; esp. medulla

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4
Q

What are the histopathologic lesions associated with anthracosis?

A

-irregular black particles within lung macrophages
-similar pigment within tracheobronchial lymph node macrophages

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5
Q

What are the characteristics of silicosis?

A

-due to inhalation of silica
-weight loss and exercise intolerance due to pulmonary fibrosis

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6
Q

What are the characteristics of tattoo ink?

A

-injected into dermis and taken up by resident macrophages
-macrophages can migrate to regional lymph nodes and pigment them

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7
Q

What are the characteristics of carotenoids?

A

-fat soluble pigments of plant origin
-examples include carotene, xanthophyll, and chlorophyll
-normally present within adipose tissue of horses, primates, poultry, and certain cattle breeds

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8
Q

What are the general characteristics of melanin?

A

-formed by melanocytes
-transferred to epithelial cells
-can be engulfed by macrophages and drained to local lymph nodes

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9
Q

How is melanin formed?

A

tyrosine is converted into dioxyphenylalanine via a copper-dependent tyrosinase

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10
Q

What is the histopathologic appearance of melanin?

A

regularly sized brown granules within cytoplasm

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11
Q

Where is melanin normally found?

A

epidermis
-hair
-hoof
-horn
-iris
-retina

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12
Q

What is the function of melanin?

A

protect against solar radiation

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13
Q

What does a lack of melanin predispose to?

A

skin cancer, such as squamous cell carcinoma

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14
Q

Which animals are predisposed to squamous cell carcinoma?

A

-white cats
-hereford cattle
-appaloosa and paint horses

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15
Q

What are the two main causes of hyperpigmentation?

A

-chronic sun exposure
-chronic irritation

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16
Q

What is melanosis?

A

congenital melanin pigmentation of unusual locations

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17
Q

Where does melanosis occur in different species?

A

-ruminants: rostral meninges, esophagus, aorta
-pigs: mammary glands, lung, liver
-dogs: oral cavity, draining lymph nodes
-cats: nose, lips, eyelids
-birds/reptiles/amphibians: testes, ovaries, serosal surfaces

18
Q

What leads to pseudomelanosis?

A

interaction between iron and bacteria

19
Q

What is the main characteristic of malignant melanoma?

A

not associated with sun exposure in animals

20
Q

What are the characteristics of malignant melanoma in dogs?

A

-found in the oral cavity and on the digits
-can be unpigmented

21
Q

What are the characteristics of malignant melanoma in horses?

A

-predisposed sites are perineum, genitalia, parotid salivary gland
-nearly always begin benign; majority will undergo malignant transformation
-gene that causes horses to turn gray predisposes to melanoma

22
Q

What are the characteristics of melanocytoma?

A

-benign melanoma
-common on haired skin of dogs
-congenital in swine, cattle, occasionally horses

23
Q

What are the types of congenital insufficient melanin?

A

-albinism/hereditary lack of tyrosinase
-piebaldism/congenital multifocal lack of pigment

24
Q

What are the types of acquired insufficient melanin?

A

-copper deficiency
-injury to skin

25
Q

What are the characteristics of hemoglobin?

A

-red pigment within erythrocytes
-postmortem red staining with hemoglobin is hemoglobin imbibition

26
Q

What is hemosiderin?

A

brown storage form of iron from breakdown of RBCs; stored within macrophages

27
Q

What is hemomelasma ilei?

A

grossly black, slightly raised serosal accumulation of hemosiderin on equine ileum

28
Q

What are the characteristics of splenic capsular plaques?

A

-commonly occur on the margins of adult canine spleens
-no clinical significance
-composed of fibrosis, mineral, hemosiderin

29
Q

What are the characteristics of bilirubin?

A

-constantly formed from breakdown of RBCs
-circulates in blood in unconjugated form; unable to be secreted
-conjugation occurs in liver; conjugated form is excreted in bile

30
Q

What are the characteristics of icterus?

A

-accumulation of bilirubin in blood and tissues
-tissues are grossly yellow; cannot see bilirubin microscopically

31
Q

What are the classifications for icterus causes?

A

-prehepatic: due to excess breakdown of RBCs
-hepatic: any liver disease that interferes with conjugation
-posthepatic: obstruction of outflow of bile from liver

32
Q

Which animals lack biliverdin reductase and are unable to develop icterus?

A

most birds

33
Q

What are the characteristics of lipofuscin?

A

-breakdown product of lipid peroxidation of cellular membranes
-“wear and tear” or aging pigments
-finely granular golden pigment within the cytoplasm
-commonly seen in myocardium, neurons, feline hepatocytes
-not visible grossly

34
Q

What are the characteristics of ceroid?

A

-breakdown product of lipid
-seen in cases of vitamin E deficiency
-grossly and histologically looks yellow

35
Q

What are the characteristics of porphyrins?

A

-photodynamic pigments which produce free radicals when exposed to sunlight
-cause photosensitization/damage to unpigmented skin

36
Q

What are the characteristics of primary photosensitization (type 1)?

A

-caused by ingestion of photodynamic pigment
-plants and drugs most common source
-reversible if offending agent is removed

37
Q

What are the characteristics of congenital porphyria (type 2)?

A

-rare inborn metabolic defect in synthesis of normal heme pigment
-bones, teeth, and urine are red-brown and autofluorescent

38
Q

What are the characteristics of hepatogenous photosensitization?

A

-chlorophyll is broken down into phylloerythrin,
a photodynamic pigment which is normally removed by the liver
-damaged liver cannot remove phylloerythrin
-only a problem in herbivores

39
Q

What is the pathogenesis of hepatogenous photosensitization?

A

-severe liver disease prevents liver from removing phylloerythrin
-phylloerythrin in blood is exposed to sunlight in unpigmented/sparsely haired skin
-production of free radicals leads to severe skin damage

40
Q

Which types of photosensitization can be caused by toxic plants?

A

-primary
-hepatogenous

SP1 General Pathology (20 decks)

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