4.9 - 1 Flashcards
what organ is well protected from infarction?
liver due to dual blood supply from portal vein & hepatic artery.
exception = transplanted liver –> severed collateral blood supply during transplantation
what is an AV fistula / shunt?
abnormal communication b/w an artery / vein, bypassing the arterioles.
note: arterioles = major source of resistance
how do fistulas affect systemic circulation?
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
what is the significance of sterile, non-destructive fibrinous vegetations along the cardiac valve cusps?
non-bacterial thrombotic endocarditis
- no associated inflammation / valvular damage
- due to hypercoagulable state
where do cancers metastasize to in the heart?
pericardium / myocardium
lambert-eaton syndrome
autoimmune paraneoplastic, affecting presynaptic calcium channels –> decreased Ach release
what is the effect of estrogen supplementation on the thyroid?
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
why do FSH levels increase during menopause?
ovarian failure –> significant dec. in estrogen production.
loss of negative fb by estrogen –> significant increase in FSH
processing of insulin?
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
enzyme responsible for chronic complications of diabetes?
aldose reductase: converts glucose to sorbitol. as blood glucose concentrations elevate, amount of glucose metabolized by aldose reductase increases –> peripheral neuropathy / cataracts
pathophysiology of atrial fibrillion
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
average atrial rate
300-500 bpm
what does a narrow QRS complex mean on EKG?
ventricular conductance pathway is normal
mitral regurgitation on cardiac catheterization
rise in LA systolic pressure due to abnormal retrograde blood flow through the mitral valve –> increased filling of LA
aortic regurg on cardiac catherization
regurgitant flow from aorta to LV –> elevated LV diastolic
+ dec. aortic diastolic pressure
aortic stenosis on cardiac catherization
obstruction of blood flow from LV to aorta during systole –> LV systolic pressure elevated, compared to aortic systolic pressure
mitral stenosis on cardiac cath
incr. LA pressure during diastole due to primary LV obstruction during filling
electrolyte profile of 21 hydroxylase deficiency
dec. glucocorticoid / mineralocorticoid synthesis –> hypotension / hyperkalemia due to salt wasting
increased production of adrenal androgens
17 hydroxylase deficiency electroclyte profile
- dec. synthesis of androgen, estrogen, cortisol
- excessive mineralocorticoid –> hypertension, hypokalemia, low renin
11 b-hydroxylase deficiency
- decreased glucocrticoid
- increased adrenal androgens
- hypertension + hypokalemia
digoxin overdose + associated cardiac problems
AV nodal block –> bradycardia, junctional escape beats, sustained junctionale scape rhythms –> v. tachy / v. fib
when do you administer packed RBCs?
acute blood loss / extreme anemia, to incr. Hb / O2 carrying capacity
when do you give platelets?
to stop significant bleeding (thrombocytopenia, qualitative platelet defects)
when do you give fresh frozen plasma?
to incr. coagulation factors (DIC, cirrhosis, warfarin overdose, TTP/HUS)
when do you give cryoprecipitate
to treat coagulation factor deficiecies w/ firbrinogen / factor VIII
(contains fibrinogen, factor 8, factor 13, vwF, fibrinectin)
