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USMLE > DIT I: Foundations > Flashcards

DIT I: Foundations Flashcards

1
Q

Name the embryonic tissue: epidermis, hair, nail, mammary gland, ant pituitary, lens, inner ear, teeth enamel, anal canal distal to pectinate

A

Surface ectoderm

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2
Q

Name the embryonic tissue: Schwann cells, glial cells, meninges, melanocytes, adrenal medulla, spiral septum, dorsal root ganglia

A

Neural crest cells

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3
Q

Name the embryonic tissue: CNS, retina, post pituitary, pineal body

A

Neural tube

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4
Q

Name the embryonic tissue: nucleus pulposis

A

Notochord

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5
Q

Fetal placental structure that secretes hCG

A

Syncytiotrophoblast

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6
Q

Maternal component of the placenta

A

Decidua basalis

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7
Q

3 germ layers that derive from epiblast

A

Ectoderm, mesoderm, endoderm

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8
Q

Teratogenic effect of: ACE inhibitors

A

Renal malformations

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9
Q

Teratogenic effect of: aminoglycosides

A

Ototoxicity, CN VIII damage

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10
Q

Teratogenic effect of: fluoroquinolones

A

Cartilage damage

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11
Q

Teratogenic effect of: cyclophosphamide

A

Ear/facial abn, limb hypoplasia, absence of digits

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12
Q

Teratogenic effect of: methotrexate

A

NTDs, abortion

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13
Q

Teratogenic effect of: tetracyclines

A

Discoloured teeth

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14
Q

Teratogenic effect of: carbamazepine and valproic acid

A

NTDs

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15
Q

Teratogenic effect of: phenytoin

A

Fetal hydantoin syndrome

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16
Q

Teratogenic effect of: lithium

A

Ebstein anomaly (tricuspid valve displaced downward into RV)

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17
Q

Teratogenic effect of: statins

A

CNS and limb abn

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18
Q

Teratogenic effect of: warfarin

A

Facial/limb/CNS abn, spontaneous abortion

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19
Q

Teratogenic effect of: isotretinoin

A

Spontaneous abortions

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20
Q

Teratogenic effect of: diethylstilbestrol (DES)

A

Clear cell vaginal adenocarcinoma

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21
Q

Teratogenic effect of: thalidomide

A

Phocomelia (limb hypoplasia)

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22
Q

By which week after conception is there fetal movement?

A

Week 8

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23
Q

By which week after conception does fetal genitalia take on visible characteristics?

A

Week 10

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24
Q

1 cause of intellectual disability in U.S.

A

Fetal Alcohol Syndrome

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25
Q

Smooth philtrum, thin upper lip, small palpebral fissures with wideset eyes, cleft lip/palate, developmental delay, microcephaly, holoprosencephaly

A

Fetal Alcohol Syndrome

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26
Q

Role of SHH gene in embryogenesis; what does a mutation cause?

A

Buds of limbs at zone of polarizing activity, organizes embryo in anterior –> posterior direction. Mut = holoprosencephaly

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27
Q

Role of Wnt7 gene in embryogenesis

A

Organization along dorsal-ventral axis

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28
Q

Role of Fgf7 gene in embryogenesis; what does a mutation cause?

A

Limb lengthening. Mut = short limbs, mut in Fgf receptor 3 = achondroplasia

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29
Q

Most common cause of congenital malformations in the U.S.

A

Alcohol use in pregnancy

30
Q

Embryological origin of tissue just proximal to pectinate line and just distal

A

Prox = endoderm. Distal = surface ectoderm

31
Q

Nuclear localization signals are rich in which 3 AAs?

A

Lys, Arg, Pro (+vely charged, can bind to -ve DNA)

32
Q

What enzyme degrades cyclins?

A

Ubiquitin protein ligase

33
Q

Which tumour suppressor proteins regulate G1 –> S?

34
Q

Which tumour suppressor proteins regulate G2 –> M?

35
Q

Which cyclins + cyclin-dependent kinases regulate G1 –> S?

A

Cyclin D + CDK4 –> Cyclin E + CDK2

36
Q

Which cyclins + cyclin-dependent kinases regulate G2 –> M?

A

Cyclin A + CDK2, Cyclin B + CDK1 (with cdc 25)

37
Q

Coat protein II (COP-II) vs COP-I

A

COP-II: anterograde trafficking (ER –> cis Golgi). COP-I: retrograde (Golgi –> ER)

38
Q

Which AAs does the Golgi apparatus modify, mainly? (3)

A

Asn, Ser, Thr

39
Q

3 methods of protein degradation

A

Lysosomal degradation, proteosomal degradation (via ubiquitin tags), Ca2+ dependent enzymes

40
Q

Deficiency in mannose phosphorylation, death by age 8, corneal clouding, coarse facies, hepatosplenomegaly, skeletal abnormalities, restricted joint movements

A

I-cell disease (No mannose-6-phosphate tagging –> lysosomal proteins secreted out of cell)

41
Q

Where is vimentin found, and what tumours can a stain of it be used to detect?

A

Connective tissue (fibroblasts, leukocytes, endothelium). Sarcomas, some carcinomas

42
Q

Where is desmin found, and what tumours can a stain of it be used to detect?

A

Muscle cells (smooth, skeletal, heart). Myosarcomas

43
Q

Where is cytokeratin found, and what tumours can a stain of it be used to detect?

A

Epithelial cells (keratin in demosomes and hemidesmosomes). Carcinomas

44
Q

Where is glial fibrillary acid proteins (GFAP) found, and what tumours can a stain of it be used to detect?

A

Astrocytes, Schwann cells, other neuroglia. Astocytomas (eg glioblastoma)

45
Q

Where is peripherin found?

46
Q

Where are neurofilaments (L, M, H molecular weight) found, and what tumours can a stain of it be used to detect?

A

Axons within neurons. Neuroblastoma, primitive neuroectodermal tumour.

47
Q

Where are nuclear lamins (A, B, C) found?

A

Nuclear envelope and DNA within

48
Q

Molecular motor proteins: dynein vs kinesin

A

Kinesin walks toward (+) end, usually anterograde. Dynein walks toward (-) end, usually retrograde.

49
Q

Situs inversus, bronchiectasis, chronic sinusitis

A

Kartagener syndrome (primary ciliary dyskinesia): due to dynein arm defect

50
Q

How does Rb protein regulate cell cycle?

A

Phosphorylation of Rb –> allows E2F txn factor to influence txn (G1 –> S)

51
Q

How does p53 influence cell cycle?

A

Controls activation of p21

52
Q

Subunits of insulin receptor and their function

A

2 alpha units bins extracellular ligand, 2 beta subunits have tyrosine kinase activity.

53
Q

Role of dynamin in receptor-mediated endocytosis

A

Pinches off vesicle formed by clathrin-coated pit

54
Q

What is the defect in familial hypercholesterolemia?

A

Mutant LDL receptor lacks coated-pit binding site but retains functioning LDL-binding site –> can bind LDL but unable to ingest it

55
Q

MOA: zileuton

A

Inhibits lipoxygenase –> decreased leukotrienes

56
Q

MOA: zafirlukast & montelukast

A

Inhibit leukotriene receptors

57
Q

Major anti-apoptotic regulator of mitochondrial permeability

58
Q

What gene product creates channels in mitochondrial membrane, and how is it activated?

A

Bax (pro-apoptotic), activated by DNA dmaage or apoptotic signal

59
Q

What substance is released from mitochondria in the process of apoptosis, and what does it activate?

A

Cytochrome C, activates caspases

60
Q

Define: pyknosis, karyorrhexis

A

Pyknosis = condensation of nuclear chromatin. Karryorhexis = nuclear fragmentation.

61
Q

What substances do cytotoxic T cells and NK cells use to induce apoptosis in cells infected with a virus?

A

Perforin, granzyme B

62
Q

4 stages of neutrophil extravasation

A

Rolling, tight binding, diapedesis, migration

63
Q

Which adhesion molecules mediate neutrophil rolling?

A

Selectins on endothelium (E, P, and L)

64
Q

Which adhesion molecules mediate neutrophil tight binding?

A

ICAM-1 on endothelium + LFA-1 on leukocytes

65
Q

Which adhesion molecules mediate neutrophil diapedesis?

66
Q

Neutrophil chemotactic signals (4)

A

C5a, IL-8, LTB4, kallikrein

67
Q

Disease and defect: delayed separation of umbilicus in newborns, recurrent bacterial infections

A

Leukocyte adhesion deficiency syndrome: due to abn integrin (LFA-1) affecting tight binding step

68
Q

Things that lower ESR

A

abnormally shaped RBCs (eg sickle), polycythemia

69
Q

What can elevated CRP predict?

A

MI, stroke, PAD, sudden cardiac death

70
Q

What cell generates fibrinogen and CRP?

A

Hepatocyte

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