Cardiovascular System



The mechanism of action of digoxin drug which increase the contractility of cardiac muscle. Its action involve closure of Na/K ATPase channels which eventually close the efflux of calcium Ca ions and increase the concentration of intracellular calcium ion


The site of action of the four major diuretic groups; thiazide diuretics, loop diuretics, acetazolamide and potassium sparing diuretics. Comparison between the four diuretics groups regarding, potency of diuretic effect, sodium and potassium excretion.

Emergency Hypertension Versus Severe Hypertension

Emergency hypertension is defined as diastolic blood pressure higher than 110 mm Hg and associated with end organ damage such as; myocardial infarction, cerebral hemorrhage and retinal damage. Whereas in severe hypertension there is no end organ damage.

Myocardial Action Potential

Action potential of cardial muscles (myyocytes) pass through four different phases; phase 0,1,2,3 and 4. It starts with rapid depolarization in phase 1, followed by rapid but short repolarization, then plateau in phase 2, which followed by rapid repolariz

Nitric Oxide And Vasodilation

Nitric oxide NO production in endothelial cells. Nitric oxide synthase NOS catalyze the production of NO from arginine amino acid. NO is transported into smooth muscle cells where it induce cascade of reactions ended by vasorelaxation. Nitric oxide donors

Renin Angiotensin System Blockers

Renin angiotensin system activate the production of angiotensin II and aldosterone which induce vasoconstriction and fluid and sodium retention. These biological vascular changes results in increased blood pressure. Angiotensin converting enzyme inhibitor