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Review / Wrong Answers > 6/22 UWorld > Flashcards

6/22 UWorld Flashcards

1
Q

Nerves involved in pupillary light reflex

A

CN II = afferent signal

CN III = eferent signal

  • Sequence of events:
    • Light in either retina = signal via CN II (optic) to pretectal nuclei in midbrain = activation of bilateral Edinger-Westphal nuclei = signal from EW nuclei to ciliary ganglion via CN III (oculomotor) = bilateral pupillary constrictor muscle activation
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2
Q

Afferent and efferent nerves of corneal reflex

A
  • Afferent = CN V1
  • Efferent = CN VII
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3
Q

What does “power” of a test tell you

A
  • Probability that the test will correctly reject the null hypothesis, when it is indeed false
  • Aka the likelihood that you will correctly identify a difference when one does exist
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4
Q

In what disease do you see Orphan Annie nuclei

A

Papillary carcinoma of the thyroid

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5
Q

Which hernia is medial/lateral to inferior epigastric vessels - direct vs. indirect

A

THINK: MD’s don’t LIe

Direct = medial

Indirect = lateral

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6
Q

MOA of Carbidopa vs. COMT inhibitors

A
  • Carbidopa = inhibits peripheral conversion of DOPA to DA, so DOPA can head to brain
    • Does not cross BBB
  • COMT inhibitors = inhibits conversion of DOPA to inactive metabolite
    • Tolcapone works both peripherally and centrally
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7
Q

MOA of Ropinirole

A

D2 receptor agonist

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8
Q

MOA of Pramipexole

A

D3 receptor agonist

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9
Q

Location of bile acid reabsorptino

A

Ileum

Maybe have decreased reabsorption in Crohns (affects terminal ileum), leading to increased ratio of cholesterol to bile within bile acid, thus predisposing to gallstones

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10
Q

What is the mutation caused by aflatoxin that leads to hepatocellular carcinoma

A

p53 mutation

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11
Q

What type of reactions are vitamin B6 used in

A

Transamination (ALT and AST)

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12
Q

What type of reactions is biotin (B7) used in

A

Carboxylation

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13
Q

Where is the cell does Vitamin C play a role in collagen synthesis?

A

Rough ER

Collagen synthesis:

  • o Signal sequence directs growing polypeptide chain into endoplasmic reticulum
  • o Signal sequence is cleaved
  • o Hydroxylation of selected proline and lysine residues (vitamin C dependent)
  • o Glycosylation of selected hydroxylysine residues
  • o Assembly of pro-alpha-chains into procallagen triple helix
  • o Procollagen transferred to Golgi apparatus and secreted into extra cellular matrix
  • o Terminal propeptides cleaved by N- and C- procollagen peptidases
  • § Ehlers Danlos can be caused by a deficiency in procollagen peptidase, leading to soluble collagen that does not properly crosslink
  • o Collagen molecules spontaneously assemble
  • o Covalent cross links formed by lysyl oxidase
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14
Q

Where in the cell/what enzyme in collagen synthesis is the problem of Ehlers Danlos

A

Extracellular matrix

  • Terminal propeptides cleaved by N- and C- procollagen peptidase
    • Ehlers Danlos can be caused by a deficiency in procollagen peptidase, leading to soluble collagen that does not properly crosslink
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15
Q

What muscle is often associated with compression of the sciatic nerve

A

Piriformis

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16
Q

What part of the penis does Sildenafil work on?

A

Vasodilation leads to increased bloodflow into corpus cavernosum

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17
Q

MOA of Ras as an oncogene

A

Oncogene = is a signal transducer (GTP-binding protein)

  • o Ras is associated with growth factor receptors in an inactive GDP-bound state
  • o Receptor binding causes GDP to be replaced with GTP, activating Ras
  • o Activated Ras sends growth signals to the nucleus
  • o Ras inactivates itself by cleaving GTP to GDP via GTPase protein
  • o Mutated Ras inhibits the activity of GTPase, thus producing a prolonged activated state of Ras
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18
Q

Crohn’s vs. Ulcerative colitis

Histology

A

Crohn - noncaseating granulomas with lymphoid aggregates

UC - crypt abscesses with neutrophils

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19
Q

What is Trousseau syndrome

A

Caused by pancreatic adenocarcinoma

  • Hypercoagulability
  • Venous thrombosis
  • Migratory thrombophlebitis
20
Q

Describe primary sclerosing cholangitis

A
  • Concentric fibrosis of the intra- and extra-hepatic bile ducts
  • Contrast imaging will show “beaded” appearance due to alternating fibrotic and dilated regions
  • Mostly occurs in men around age 40
  • Associated with (+) pANCA and Ulcerative colitis
  • Increased risk for cholangiocarcinoma

Vs. Primary biliary cholangitis which is autoimmune (anti-mitochondrial) with lymphocytes/granulomas

21
Q

Describe fluid compartment/composition of body

A
  • 60-40-20 rule
  • 60% of body mass is water, of that 60%:
    • 40% is ICF
    • 20% is ECF
      • Only 25% of ECF is plasma
22
Q

When does glucose begin to appear in the urine

A
  • Glucose is completely reabsorbed up until plasma glucose level ~200 mg/dL
    • This is when glucosuria begins (threshold)
  • At ~375 mg/min, all transporters are fully saturated
23
Q

Describe the defect in type 1 renal tubular acidosis, hyper/hypokalemia, urine pH

A
  • Distal renal tubular acidosis à defect in collecting tubule
  • Alpha-intercalated cells are unable to secrete H+ à acidosis
  • Hypokalemia
  • Urine pH will be > 5.5 (because no H+ in urine)
  • Causes:
    • Amphotericin B toxicity, analgesic nephropathy, congenital anomalies (obstruction) of urinary tract
24
Q

Describe the defect in type 2 renal tubular acidosis, hyper/hypokalemia, urine pH

A
  • Proximal renal tubular acidosis à defect in proximal tubule
  • Impaired HCO3- reabsorption à Increased HCO3- excretion à acidosis
  • Hypokalemia and hypophosphatemia
  • Urine pH < 5.5 (urine is acidified by a-intercalated cells in collecting tubule)
  • Causes:
    • Fanconi syndrome, carbonic anhydrase inhibitors
25
Q

Describe the defect in type 4 renal tubular acidosis, hyper/hypokalemia, urine pH

A
  • Hyperkalemic renal tubular acidosis
  • Due to hypoaldosteronism à decreased K+ secretion à hyperkalemia
  • Hyperkalemia prevents collecting tubules from generating NH4+ à impaired ammonium excretion
  • Urine pH < 5.5 (decreased aldosterone = decreased Na+ reabsorption = increased Na+ in lumen = positively charged lumen)
  • Causes:
    • Decreased aldosterone production (diabetic hyporeninism, ACE inhibitors, ARBs, NSAIDs, heparin, cyclosporine, adrenal insufficiency)
    • Aldosterone resistance (K+ sparing diuretics, nephropathy due to obstruction, TMP/SMX)
26
Q

What is fanconi syndrom

A
  • Reabsorptive defect of the PCT
  • Associated with increased excretion of amino acids, glucose, HCO3-, and PO43-
  • Causes:
    • Hereditary defects, ischemia, multiple myeloma, nephrotoxins/drugs (cisplatin, tenofovir, expired tetracyclines), lead poisoning
27
Q

What is Winter’s fomula and what does it do?

A
  • Predicted respiratory compensation for metabolic acidosis
    • If measured pCO2 > predicted pCO2 – concomitant respiratory acidosis
    • If measure pCO2 < predicted pCO2 – concomitant respiratory alkalosis
  • pCO2 = 1.5(HCO3-) + 8 +/- 2
28
Q

MOA of alpha-toxin of C. perfringens

A

Toxin is a lecithinase - degrades lecithine, a component of phospholipid membranes, leading to cell death and necrosis

29
Q

Presentation of Alport syndrome

A

Presents as isolated hematuria, sensory hearing loss, and ocular disturbances

“Can’t see, can’t pee, can’t hear high C”

30
Q

Where are immune complex depositions seen in diffuse proliferative glomerulonephritis

A

DPGN seen in Lupus

Immune complexes seen subendothelially and within the mesangium

31
Q

What type of stone is a struvite stone?

A

Ammonium magnesium phosphate stone

  • Major risk factor = Urease + bacteria
  • Recall:
    • Urea is broken down by urease into NH3 and CO2
    • NH3 converted to NH4+ which can combine with magnesium and phosphate
32
Q

Describe histology of renal cell carcinoma

A

Will see polygonal clear cells filled with accumulated lipids and carbohydrates

33
Q

Tumors that secrete EPO

A
  • Potentially Really High Hematocrit
    • Pheochromocytoma
    • Renal cell carcinoma
    • Hepatocellular carcinoma
    • Hemangioblastoma
34
Q

What is WAGR complex

A
  • Wilms tumor, Aniridia (absence of iris), Genitourinary malformation, mental/motor Retardation
35
Q

What disease is associated with thyroidization of the kidney

A

Chronic pyelonephritis

Eosinophilic casts dilate the tubules, causing the tubules to have a colloid/thyroid-like appearance

36
Q

What disease is associated with eosinophils in urine

A

Acute interstitial nephritis

Acute interstitial renal inflammation that results in acute renal failure

Presentation:

Fever, rash, eosinophilia, azotemia

37
Q

Describe medullary cystic disease

A
  • Can lead to fibrosis and progressive renal insufficiency
    • Will present as cysts in the collecting ducts and shrunken kidney due to fibrosis
    • Vs. most other cystic diseases which will present with cystic dilation of kidney
38
Q

Describe the organ systems associated with each of the muscarinic receptors (M1, M2, M3)

A

M1 - enteric and CNS

M2 - heart

M3 - bladder, smooth muscles of eye

39
Q

What part of the nephron has most dilute urine

A

Distal convoluted tubule

40
Q

MOA of polyethylene glycol

A

Sketchy = PEG

Osmotic laxative

41
Q

What is Meniere disease

A
  • Increased pressure and volume of endolymph
  • Features:
    • Recurrent vertigo
    • Ear fullness/pain
    • Unilateral hearing loss and tinnitus
42
Q

MRI findings in multiple sclerosis

A

Periventricular plaques (areas of oligodendrocyte loss and reactive gliosis)

43
Q

Describe presentation of Vestibular neuritis

A
  • Vestibular neuritis (labyrinthitis):
  • Inflammation of vestibular nerve
    • Features:
      • Single episode that can last days
      • Severe vertigo but no hearing loss
44
Q

Presentation of Creutzfeldt-Jakob disease

A

Rapidly progressive dementia + ataxia + startle myoclonus

45
Q

Homogentisate oxidase usually converts what to what?

A

Tyrosine to fumarate

46
Q

Describe the meaning of “permissiveness” in reference to drug-drug interaction

A

When drug 1 allows drug 2 to exert maximal effects

But drug 1 alone does not have similar effects (that would be considered synergistic or additive)

47
Q

Deficiency of CD55 or CD59 indicates what disorder?

A

Paroxysmal nocturnal hemoglobinuria

Due to deficiency of GPI, which usually anchors DAP (CD55) to RBC membrane to protect from complement destruction

Review / Wrong Answers (140 decks)

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