0 - USMLE Step 1 > Uworld > Flashcards

Uworld Flashcards

(58 cards)

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1
Q

List 8 locations where you find type I collagen?

A
  • Dermis
  • Bone
  • Tendons
  • Ligaments
  • Dentin
  • Cornea
  • Blood vessels
  • Scar tissue
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2
Q

What type of collagen is affected in osteogenesis imperfecta?

A

Type I collagen

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3
Q

List 3 locations where you find type II collagen

A
  • Cartilage
  • Vitreous humor
  • Nucleus pulposus
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4
Q

List 7 locations where you find type III collagen?

A
  • Skin
  • Lungs
  • Intestines
  • Blood vessels
  • Bone marrow
  • Lymphatics
  • Granulation tissue
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5
Q

Type IV collagen is found where?

A

Basement membranes

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6
Q

Due to the overlap of normal behavior in preschoolers and sx’s of ADHD, the diagnosis is not given before what ages?

A

4-5 y/o

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7
Q

What is the embryological defect comprising Pierre-Robin sequence and what is seen in these children?

A
  • Severe micrognathia results in posterior displacement of the tongue (glossoptosis)
  • Prevents further fusion of the secondary palate (cleft palate)
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8
Q

Which blot procedure is used for DNA, mRNA, and protein?

A
  • DNA = Southern blot
  • mRNA = Northern blot
  • Protein = Western blot
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9
Q

The best method for determining whether a gene is being expressed is by using what type of blot?

A

Northern blot for mRNA; will show if gene of interest is being transcribed

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10
Q

Which interleukin is produced by macrophages infected by mycobacteria, which in turn stimulates T cells and NK cells to produce IFN-gamma?

A

IL-12

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11
Q

Autosomal recesssive deficiencies of what receptor result in disseminated mycobacterial disease in infancy or early childhood?

A

IFN-gamma receptor

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12
Q

Leukocyte adhesion deficiency is a rare immunodeficiency resulting from a defect in what?

A
  • CD18
  • Present w/ delayed separation of umbilical cord, recurrent cutaneous infections w/o pus formation, and poor wound healing
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13
Q

Injury to a branch of which nerve during appendectomy causes decreased sensation at the suprapubic region?

A

Anterior branch of Iliohypogastric n.

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14
Q

Which nerve arises from L2-L4 roots and innervates the skin of the medial thigh + provides motor function to the adductor ms. of the LE?

A

Obturator n.

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15
Q

Which nerve arising from L1 accompanies the spermatic cord through the superficial inguinal ring providing sensation to the upper and medial thigh and parts of the external genitalia?

A

Ilioinguinal n.

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16
Q

Left ventricular gallops (S3 and/or S4) are best heard how?

A

Using bell over the cardiac apex while pt is left lateral decubitus and listening at end of exhalation

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17
Q

Sudden upward jerking of the arm at the shoulder can cause injury to which nerves?

A

Lower trunk of brachial plexus (C8-T1) contributing to median and ulnar n.

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18
Q

Which fetal anomalies associated with decreased fetal swallowing can lead to polyhydramnios?

A
  • GI obstruction: esophageal, duodenal, or intestinal atresia
  • Anencephaly
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19
Q

Brown Sequard syndrome results from hemisection of the spinal cord and is characterized by what 3 findings?

A
  • Ipsilateral spastic paralysis (due to corticospinal tract injury)
  • Ipsilateral loss of tactile/vibratory/position sensation (dorsal columns)
  • Contralateral loss of pain and temp (spinothalamic tract) 1-2 levels below the lesion
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20
Q

In patients with PKU what AA becomes essential and why?

A

Tyrosine as it cannot be synthesized from phenylalanine in these pt’s

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21
Q

Which immune cells play a prominent role in defense against parasitic infection; predominantly via what substance?

A
  • Eosinophils
  • Release major basic protein from their granules, which acts as a potent toxin
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22
Q

Which fungi is associated with branching hyphae (25°C) and on biopsy is large, round yeasts w/ doubly refractile wall and single broad-based bud?

A

Blastomyces dermatidis

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23
Q

Which fungi is associated with oval yeast cells found within macrophages?

A

Histoplasma capsulatum

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24
Q

Biopsy of which fungal infection will show cells covered in budding blastoconidia?

Study These Flashcards
A

Paracoccidioides brasiliensis

25
Respiratory bronchioles lack which 2 features found in the bronchi?
**Cartilage** and **glands**
26
Acute intermittent porphyria (AIP) may result from an autosomal dominant defect in which enzyme?
Porphobilinogen deaminase (PBGD)
27
What is the 5 P's mnemonic for the clinical manifestations of Acute Intermittent Porphyria?
- **P**ainful abdomen - **P**ort wine - colored urine - **P**olyneuropathy - **P**sychological disturbance - **P**recipitated by drugs (and alcohol and starvation)
28
A patients urine turning black when exposed to air is a characteristic finding of what disease?
**Alkaptonuria** (autosomal recessive); deficiency of **homogentisic acid dioxygenase**
29
What is the function of T-tubules found in striated muscle?
- During contraction, allow _depolarization_ impulse to **rapidly propogate** thru interior of muscle fiber - Ensures Ca2+ release occur _uniformly_ throughout the fiber, allowing for **synchronized contraction** of **myofibrils** in each cells
30
Describe the route of an embolus leading to retinal artery occlusion.
**Internal carotid** --\> **Ophthalmic a.** --\> **Retinal a.**
31
Intellectual disability, gait or posture abnormality, eczma, and a musty body odor are signs of what disease; inherited how?
**PKU**; autosomal _recessive_
32
Which cell structure can be identified on electron microscopy by their characteristic double membrane and wavy cristae?
**Mitochondria**
33
What is the most common non-nuclear DNA found in eukaryotic cells, which resembles prokaryotic DNA (small circular chromosome)?
**Mitochondrial DNA** (**mtDNA**)
34
What is the karyotype of a complete vs. partial hydatidiform mole?
- **Complete**: 46,XX - **Partial**: 69,XXY or 69,XXX
35
What is the embryological defect leading to Tetralogy of Fallot?
Abnormal **neural crest cell** migration --\> _anterior_ and _cephalad_ deviation of **infundibular septum**
36
What is the most common trigger for atrial fibrillation?
_Aberrant electrical foci_ in the **pulmonary veins** near their ostia into the left atrium
37
An irregularly irregular rhythm with variable R-R intervals and absence of P wavs on ECG is consistent with what?
**Atrial Fibrillation**
38
What is Hartnup disease; inheritance pattern; major clinical manifestations?
- Autosomal **recessive** disorder due to _inactivating_ mutations affecting **neutral AA transporter**; particularly affecting **tryptophan** - Clinical manifestations due to **niacin** deficiency: **pellagra-like skin eruptions** + **cerebellar ataxia** - Excessive amounts of **neutral AA's** in the urine
39
What is unique about DNA polymerase I?
- _Only_ **prokaryotic** polymerase that has **5' to 3' exonuclease activity**; in addition to **3' to 5' polymerase/exonuclease** activities - Functions to remove **RNA primer** and **repair damaged DNA** sequences
40
Describe the murmur and location heard with patent ductus arteriosus (PDA)?
**Continous murmur** heard best in the left _infraclavicular_ region with **maximal intensity** at **S2**
41
Optic tract lesions result in what type of visual field defect?
**Contralateral homonymous hemianopia** _and_ relative **afferent** pupillary defect (**Marcus Gunn pupil**)
42
_Budding_ yeasts with _thick capsules_ are characteristic of which organism?
***Cryptococcus neoformans***
43
Where is the majority of the water filtered by the glomeruli reabsorbed, regardless of hydration status?
**Proximal tubules**
44
How do you calculate attack rate of a study?
of people affected / total # of people at risk
45
Primary oocytes arrest in which phase of cell cycle until ovulation and then secondary oocytes arrest in which phase until fertilization?
- **Primary oocytes** in **prophase** of **meiosis I** until **_ovulation_** - **Secondary** **oocytes** in **metaphase** of **meiosis II** until **_fertilization_**
46
Which enzyme released by injured hepatocytes and bacteria hydrolyzes bilirubin glucuronides to unconjugated bilirubin leading to pigmented stones?
**Beta-glucuronidase**
47
Why must patients receive Mefloquine chemoprophylaxis for 4 weeks upon return from trip to areas where *P. falciparum* is endemic?
- To ensure that parasistes released from liver are destroyed when they infect RBC's (liver schizonts rupture over 8-30 days) - Mefloquine actively destroyes replicating parasites within RBC's, however, is **inactivated** in **liver** and has **_no efficacy_** against **hepatic schizonts**
48
Gallstone ileus results from passage of a large gallstone through a cholecystenteric fistula into the small bowel where it ultimately causes obstruction where?
**Ileum**
49
Primary biliary cholangitis presnts with similar histopathological findings in the liver as what other condition?
**GVHD**
50
Isolated systolic HTN is due to what?
**Age**-related **stiffness** and **decreased compliance** of the **aorta** and **major peripheral arteries**
51
What is the effect of an increase in estrogen activity as seen in pregnancy or post-menopausal estrogen replacement therapy?
↑ the level of **TBG** --\> ↑ in **total T4 levels** as well as **total T3**
52
What is the gold standard test for detecting a chromosomal microdeletion?
**FISH**
53
Vascular beds in which organ are unique in that as tissue O2 content decreases the arterial/arteriolar resistance increases?
**Lungs** --\> diverts blood away from underventilated lung regions toward well-ventilated lung areas to minimize V/Q mismatch = **efficent gas exchange**
54
Serum levels of what are the most sensitive test for hypothyroidism?
**TSH**
55
A 2-year old girl with ambiguous genitalia, HTN, and hypokalemia is most likely to have a deficiency in what?
**11ß-hydroxylase** = **Congenital adrenal hyperplasia**
56
What is the most common GI abnormality associated with Down Syndrome?
**Duodenal Atresia**: first few days of life, bilious emesis; "double-bubble" sign
57
What is the hallmark of peroxisomal disorders (i.e., Zellweger syndrome, Adrenoleukodystrophy)?
Buildup of VLCFA's and branched-chain (i.e., phytanic) FA's due to impaired oxidation
58
What is the most common cause of alarming bloody or serosanguineous (i.e., blood tinged) nipple discharge; what is seen histologically?
- **Intraductal papilloma** - Proliferation of **papillary cells** in a **duct** or **cyst wall** with **fibrovascular core**
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