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Flashcards in USMLE Pathology Deck (62):
1

PaO2 and SaO2 levels in CO poisoning?

PaO2 normal, SaO2 decreased

2

What cells can only undergo hypertrophy?

Skeletal muscle, heart, neurons

3

What cellular functions stop working with hypoxia?

Na/K pumps = swelling, Ca pumps = Enzyme activation, Aerobic to anaerobic glycolysis = lactic acidosis, lowers pH

4

Where is the electron transport chain located?

Inner mitochondrial membrane

5

What are the three stages of cell death?

Pyknosis (shrinks down), karyorrhexis (nucleus breaks down), karyolysis (broken down)

6

When do you get a red infarct?

When blood reenters an infarcted area (of loosely connected tissue)

7

Why is necrosis in the brain liquefactive?

Because microglial cell enzymes destroy everything

8

What situations do you see liquefactive necrosis in?

Brain ischemia, abscess, pancreatitis

9

How do you distinguish dystrophic calcification from metastatic calcification?

Dystrophic = normal Ca PO4 in serum, will be elevated in metastatic

10

What are the three apoptotic pathways?

1) Intrinsic mitochondrial pathway (Bcl2, cytC)
2) Extrinsic receptor-ligant pathway (FasL, TNF)
3) Cytotoxic T cell pathway (perforin, granzymes)

11

Delayed separation of umbilical cord?

Leukocyte adhesion deficiency

12

What factors mediate pain?

PGE2 and bradykinin

13

What factors mediate inflammation

Mast cells, arachidonic acid, TLRs, complement, Hageman's factor

14

What are mast cells activated by?

Tissue trauma, C3a, C5a, and cross linking by IgE

15

What factors are responsible for neutrophil chemotaxis?

LTB4, C5a, IL-8, bacterial products

16

What is an important example of TLRs in action?

CD14 on macrophages binds LPS on G-ve bacteria to activate NfKB

17

Features of Chediak Higashi syndrome?

Dysfunctional primary hemostasis
Albinism
Peripheral neuropathy
Infections (pyogenic)
Neutropenia
Giant granules in leukocytes

18

Recurrent infections by catalase positive organisms?

Chronic granulomatous disease

19

How do macrophages continue acute inflamm?

IL-8

20

How do macrophages initiate resolution and healing?

IL-10, TGF-B

21

How are CD4 T cells activated?

TCR to MHC II with antigen and B7 to CD28 on T cell

22

How are CD8 T cells activated

TCR to MHC I with antigen and IL-2 from TH1 CD4+ helper cells

23

What cytokines are produced by CD4+ Th1 cells?

Helps CD8 T cells
IL-2 - promotes T cell proliferation, IFN-gamma: activates macrophages

24

What cytokines are produced by CD4+ Th2 cells?

Helps B cells
IL-4 - switch to IgG, IgE
IL-5 eosinophils and switch to IgA
IL-10 inhibits Th1 subtype

25

How are B cells activated independent of T cells?

BCR binds to antigen and becomes plasma cell expressing IgM, IgD

26

How are B cells activated by T cells?

B cell presents antigen on MHC II to CD4+ Th2 cells, CD40 on B cell binds CD40L on T cell --> IL4/IL5 for class switching

27

What are the key cells in granulomas?

Epithelioid histiocytes (surrounded by giant cells and rim of lymphocytes)

28

How are granulomas activated?

Macrophage presents antigen on MHC II to T helper cell and secretes IL-12 to turn it into TH1 cell. TH1 cell secretes IFN-gamma to turn macrophages into EH cells

29

What is the cause of DiGeorge syndrome?

Microdeletion 22q11

30

High yield cause of SCID?

Adenosine deaminase deficiency (builds up in lymphocytes, kills it)

31

Chronic candida, adrenal failure, hypoparathyroidism. Dx?

Autoimmune polyendocrine syndrome (AIRE deficiency)

32

What receptors are expressed on Treg cells?

CD4, CD25 (IL2-R), FOXP3

33

How do Tregs do their work?

Compete with B7 with CTLA4 and release IL-10/TGF-B to shut down MHC II, DC, macrophages, and B7

34

How does peripheral tolerance work?

Induces anergy if TCR binds MHC II without B7/CD-28 (absent in non-inflammatory states), or self expresses Fas to apoptose

35

Features of IPEX syndrome?

Immune dysfn, polyendocrinopathy, enteropathy, x-linked

36

What causes hyper IgM syndrome?

CD40/CD40L mutation = only IgMs produced, susceptible to pyogenic infections

37

What risks associated with common variable immunodeficiency?

Bacterial, giardia, enterovirus infxns + risk of AI disease/lymphoma

38

What makes up granulation tissue?

Blood vessels, fibroblasts (for T3 collagen), and myofibroblasts

39

T1 collagen?

Bone

40

T2 collagen?

Cartilage

41

T3 collagen?

Granulation tissue, embryonic tissue, blood vessels

42

T4 collagen?

Basement membrance

43

TGF-alpha

Epithelium and fibroblast GF

44

TGF-beta

Fibroblast GF and anti inflammatory

45

PDGF

Endothelium, smooth muscle, fibroblast GF

46

FGF

Angiogenesis and skeletal development

47

VEGF

Angiogenesis

48

What kind of collagen is seen in keloid scars?

T3 collagen

49

Aflatoxins

HCC, in Africa and stored grains

50

Alkylating agents

Lymphoma, leukemia

51

Alcohol

SqCC of oropharynx & upper esophagus, HCC, pancreatic cancer

52

Arsenic

SqCC of skin, lung cancer, angiosarcoma of liver

53

Nitrosamine

Intestinal type stomach cancer

54

Vinyl chloride

Angiosarcoma of liver

55

EBV cancer associations?

Nasopharyngeal cancer, Burkitt lymphoma, CNS in AIDS

56

HHV 8

Kaposi's sarcoma in E. European males, AIDS, transplant

57

HTLV-1

ATLL

58

Ionizing

AML, CML, Papillary thyroid carcinoma

59

Ret

Associated with medullary carcinoma of thyroid in MEN2A/2B

60

PDFG-B overexpression

Astrocytoma

61

What is ABL responsible for?

9:22 translocation seen in CML and adult B-ALL

62

What are you at risk of with germline mutation of Rb?

Bilateral retinoblastomas and osteosarcoma