4.9 - 1

Question 1

what organ is well protected from infarction?

Answer 1

liver due to dual blood supply from portal vein & hepatic artery.

exception = transplanted liver –> severed collateral blood supply during transplantation

Question 2

what is an AV fistula / shunt?

Answer 2

abnormal communication b/w an artery / vein, bypassing the arterioles.

note: arterioles = major source of resistance

Question 3

how do fistulas affect systemic circulation?

Answer 3

AV increases preload by increasing rate / volume of blood flow back to the heart –> higher EDV.

total peripheral resistance decreases b/c blood bypasses the arterioles –> dec. afterload

Question 4

what is the significance of sterile, non-destructive fibrinous vegetations along the cardiac valve cusps?

Answer 4

non-bacterial thrombotic endocarditis

• no associated inflammation / valvular damage
• due to hypercoagulable state

Question 5

where do cancers metastasize to in the heart?

Answer 5

pericardium / myocardium

Question 6

lambert-eaton syndrome

Answer 6

autoimmune paraneoplastic, affecting presynaptic calcium channels –> decreased Ach release

Question 7

what is the effect of estrogen supplementation on the thyroid?

Answer 7

estrogen decreases catabolism of TBG.
INcreased in TBG –> increase in total T4 (bound T4 + free T4) + otal T3.

free thyroid hormones = normal levels –> patients are euthryoid w/ normal TSH levels

Question 8

why do FSH levels increase during menopause?

Answer 8

ovarian failure –> significant dec. in estrogen production.

loss of negative fb by estrogen –> significant increase in FSH

Question 9

processing of insulin?

Answer 9

1) proinsulin deposited in RER
2) transported to Golgi
3) convertase cleaves proinsulin –> insulin, C peptide + 2 amino acids
4) c peptide / insulin packed into secretory granules –> secreted into ECM

Question 10

enzyme responsible for chronic complications of diabetes?

Answer 10

aldose reductase: converts glucose to sorbitol. as blood glucose concentrations elevate, amount of glucose metabolized by aldose reductase increases –> peripheral neuropathy / cataracts

Question 11

pathophysiology of atrial fibrillion

Answer 11

1) atrial excitability increases, so multiple impulses are generated in areas other than the SA node + disyncrony
2) multiple-reentrant loops arise
3) abnormal atrial impulse reaching the AV node –> spread to the ventricles
4) limited by AV node refractory period

Question 12

average atrial rate

Answer 12

300-500 bpm

Question 13

what does a narrow QRS complex mean on EKG?

Answer 13

ventricular conductance pathway is normal

Question 14

mitral regurgitation on cardiac catheterization

Answer 14

rise in LA systolic pressure due to abnormal retrograde blood flow through the mitral valve –> increased filling of LA

Question 15

aortic regurg on cardiac catherization

Answer 15

regurgitant flow from aorta to LV –> elevated LV diastolic

+ dec. aortic diastolic pressure

Question 16

aortic stenosis on cardiac catherization

Answer 16

obstruction of blood flow from LV to aorta during systole –> LV systolic pressure elevated, compared to aortic systolic pressure

Question 17

mitral stenosis on cardiac cath

Answer 17

incr. LA pressure during diastole due to primary LV obstruction during filling

Question 18

electrolyte profile of 21 hydroxylase deficiency

Answer 18

dec. glucocorticoid / mineralocorticoid synthesis –> hypotension / hyperkalemia due to salt wasting
increased production of adrenal androgens

Question 19

17 hydroxylase deficiency electroclyte profile

Answer 19

• dec. synthesis of androgen, estrogen, cortisol

- excessive mineralocorticoid –> hypertension, hypokalemia, low renin

Question 20

11 b-hydroxylase deficiency

Answer 20

• decreased glucocrticoid
• increased adrenal androgens
• hypertension + hypokalemia

Question 21

digoxin overdose + associated cardiac problems

Answer 21

AV nodal block –> bradycardia, junctional escape beats, sustained junctionale scape rhythms –> v. tachy / v. fib

Question 22

when do you administer packed RBCs?

Answer 22

acute blood loss / extreme anemia, to incr. Hb / O2 carrying capacity

Question 23

when do you give platelets?

Answer 23

to stop significant bleeding (thrombocytopenia, qualitative platelet defects)

Question 24

when do you give fresh frozen plasma?

Answer 24

to incr. coagulation factors (DIC, cirrhosis, warfarin overdose, TTP/HUS)

Question 25

when do you give cryoprecipitate

Answer 25

to treat coagulation factor deficiecies w/ firbrinogen / factor VIII

(contains fibrinogen, factor 8, factor 13, vwF, fibrinectin)