Cardiophile MD Archive

All of the following molecules are involved in the antithrombotic mechanisms of the endothelial cell except: A. Heparan sulphate B. Thrombomodulin C. t-PA D. Lipoprotein (a) Answer: D. Lipoprotein (a) Heparan sulfate proteoglycan molecules on the surface of the endothelial cell act as a co-factor for antithrombin III. Thrombomodulin binds thrombin molecules and exerts antithrombotic [...]

All of the following are true of endothelium dependent hyperpolarizing factor (EDHF) except: A. Hyperpolarizes vascular smooth muscle B. Acts via nitric oxide C. Metabolite of arachidonic acid D. Produced by cytochrome P-450 epoxygenase pathway Answer: B. Acts via nitric oxide Endothelium-dependent hyperpolarizing factor (EDHF) hyperpolarizes vascular smooth muscle and dilates arteries by opening calcium-activated [...]

All of the following are determinants of myocardial oxygen consumption except: A. Systolic pressure B. Diastolic pressure C. Heart rate D. Left ventricular contractility Answer: B. Diastolic pressure The major determinants of myocardial oxygen consumption are heart rate, systolic pressure and left ventricular contractility. The product of systolic pressure and heart rate is known as [...]

Mechanisms of chronic preconditioning include all the following except: A. Downregulation of iNOS B. Upregulation of COX-2 C. Opening of mitochondrial K+ATP channels D. Involves protein synthesis Answer: A. Downregulation of iNOS Chronic or delayed preconditioning involves protein synthesis with upregulation of iNOS (inducible nitric oxide synthase), cyclooxygenase (COX-2) and opening of mitochondrial K+ATP channels. [...]

Extravascular compressive component of coronary vascular resistance is: A. R1 B. R2 C. R3 D. R4 Answer: C. R3 R1 is the epicardial conduit resistance, which is negligible unless the obstruction is more than 50% of luminal diameter. R2 is the microcirculatory resistance in the small arteries and arterioles. R3 is compressive resistance and is [...]