UWorld_1.13

Question 1

Pathophysiology of centriacinar emphysema

Answer 1

• centriacinar emphysema = due to chronic, heavy smoking
• infiltrating neutrophils and macrophages release proteinases (esp. elastase) ==> damage of Type 1 pneumocytes

Question 2

Characteristics of Fabry disease

Answer 2

• inherited deficiency of alpha-galactosidase A ==> accumulation of globoside ceramide trihexose ==>
  
  • hypohidrosis
  • acroparesthesia = episodic, burning neuropathy @ extremities
  • angiokeratomia = dark red, non-blanching macules/papules between umbilicus and knees
• w/out enzyme replacement ==> renal failure

Question 3

Gene products of HIV virus

Answer 3

• gag, pol, env = structural genes
  
  • gag ==> p24 and p7 (nucleocapsid proteins)
  • pol ==> reverse transcriptase
  • env ==> gp120 and gp41 (envelope glycoproteins)
• tat, rev = regulatory genes = required for replication

Question 4

Mortality of breast vs. colon vs. lung vs. stomach vs. ovarian cancers in women

Answer 4

• lung cancer = highest mortality rate; sharp increase over last 40 years
• breast cancer
  
  • most common non-skin
  • mortality rates relatively low (vs. lung)
• colon cancer = mortality decreased over last 40 years
• stomach cancer = previously common, drastically reduced mortality
• ovarian = low, steady mortality

Question 5

Right testicular vein ==>

Left testicular vein ==>

Answer 5

• Pampiniform plexus ==> Right testicular vein ==> IVC
• Pampinoform plexus ==> Left testicular vein ==> left renal vein

Question 6

Atypical lymphs of blood smear in infectious mono =

Answer 6

activated CD8+ T-lymphocytes ==> destroy virally infected B cells

Question 7

Potential heart murmur in patient w/extertional dyspnea/syncope

Answer 7

• Aortic stenosis ==> abnormal pressure gradient between left ventricle and aorta during systole
  
  • systolic murmur, crescendo-decrescendo

Question 8

K filtration @ kidney

Answer 8

1. K flows freely at glomerulus ==> 100% of filtered load in tubule
2. ~65% of K reabsorbed @ proximal tubule ==> ~35% of filtered load in tubule
3. 25-30% more K reabsorbed at thick ascending LOH ==> 5% of filtered load in tubule
4. **First 3 steps consistent regardless of K status**
5. @ low serum levels of K:
   
   1. alpha-intercalated cells (@ distal tubule/collecting duct) reabsorb K via H/K/ATPase ==> as low as 1% of filtered load in tubule
6. @ high serum levels of K:
   
   1. principle cells (@distal tubule/CD) secrete K via apical K channels ==> as high as 110% of filtered load in tubule

Question 9

Pharyngeal/Aortic Arch 1 ==> CN? Key structures?

Answer 9

• Trigeminal (CN V)
• Maxillary artery (portion)

Question 10

Pharyngeal/Aortic Arch 2 ==> CN? Key structures?

Answer 10

• Facial (CN VII)
• Stapedial artery (regresses)

Question 11

Pharyngeal/Aortic Arch 3 ==> CN? Key structures?

Answer 11

• Glossopharyngeal (CN IX)
• Common carotid a.
• prox. interal carotid a.

Question 12

Pharyngeal/Aortic Arch 4 ==> CN? Key structures?

Answer 12

• sup. laryngeal branch of vagus (CN X)
• true aortic arch
• subclavian arteries

Question 13

Pharyngeal/Aortic Arch 5 ==> CN? Key structures?

Answer 13

obliterated

Question 14

Pharyngeal/Aortic Arch 6 ==> CN? Key structures?

Answer 14

• recurrent laryngeal branch of Vagus (CN X)
• pulmonary arteries
• ductus arteriosus