Week 2 Block 6: PCR

Question 1

(1) Tissue/Vessels extracting most oxygen from blood (2) Main mechanisms

Answer 1

(1) Myocardium oxygen extraction exceeds that of any other tissue or organ body. See SB for details. (2) Hypoxia and adenosine accumulation increase cardiac perfusion, which is main mechanism by which increases in myocardial oxygen demand are satisfied

Question 2

Saphenous vein best harvested from what site

Answer 2

Just inferolateral to pubic tubercle; See SB for details on saphenous vein course

Question 3

IVC forms union of what 2 vessels, and at what spinal level

Answer 3

R & L common iliac veins at level of L4-L5; See U World for CT

Question 4

(1) Dx: 5 yo male with bounding pulse, thrill palpated over upper left sternal edge, continuous murmur heard over area (2) Surgeon should intervene on derivative of which embryologic strx

Answer 4

(1) Patent ductus arteriosus (2) 6th aortic arch

Question 5

Tx for diabetic ketoacidosis & its mechanism/effects

Answer 5

IV hydration with normal saline and insulin. Result in decreases in serum glucose, osmolality, and potassium, as well as increases in serum bicarbonate and sodium

Question 6

Cutaneous, strawberry-type capillary hemangiomas: (1) Definition (2) Fate

Answer 6

(1) Common, benign, congenital tumors which are composed of unencapsulated aggregates of closely packed, thin-walled capillaries (2) Initially strawberry hemangiomas grow in proportion to growth of child, before eventually regressing. In 75 to 95% of cases, vascular tumor will regress completely by age 7

Question 7

High intraplaque activity of which enzyme would predispose patient to MI

Answer 7

Metalloproteinases (secreted by inflammatory macrophages in intima), which degrade collagen, reducing plaque stability