ANS-CVS 3 Flashcards
<p>how to count BP?</p>
<p>cardiac output x total peripheral resistance</p>
<p>how to count cardiac output(CO)?</p>
<p>heart rate (HR) x stroke vol (SV)</p>
<p>define preload</p>
<p>the ability of the ventricles to stretch and fill with blood</p>
<p>define afterload</p>
<p>the ability of the ventricle to empty by pushing against systemic vascular resistance</p>
<p>parasympathetic effects on the heart</p>
<p>- input via vagus nerve causes decrease HR (dominates)</p>
<p>sympathetic effects on the heart </p>
<p>- input to SA node causes increase HR- increase heart contractility</p>
<p>which type of adrenoreceptors (sympathetic nerves) dilate the arteries/veins?</p>
<p>B2 adrenoreceptors</p>
<p>function of renin</p>
<p>- secreted by the kidney to increase BP or blood volume- converts angiotensinogen -> angiotensin 1</p>
<p>function of angiotensin-converting enzyme (ACE)</p>
<p>converts angiotensin 1 -> angiotensin 2 in lung</p>
<p>actions of angiotensin 2</p>
<p>1. cause vasoconstriction = increase TPR2. cause release of aldosterone -> promote Na & water reabsorption in kidney -> increased blood volume3. negative feedback to release renin4. stimulate thirst in hypothalamus5. stimulate sympathetic outflow`</p>
<p>Principles of treatment of hypertension</p>
<p>1. Reduce left ventricular systolic performance - negative inotropes (beta blockers) - Calcium channel blockers (verapamil)2. Reduce blood volume - Diuretics (thiazide, loop diuretics & potassium sparing diuretic)3. Reduce venous tone and thus venous return - Central sympatholytics (clonidine) act to reduce synpathetic tone4. Reduce arterial tone (resistance) </p>
<p>drugs to reduce arterial tone in hypertension eg: resistance</p>
<p>- ACE inhibitors- angiotensin receptor blockers- K+ channel openers- NO donors- A1- blockers- mixed A and B blockers </p>
<p>treatment of cardiac failure</p>
<p>1. diuretics and nitrates (A-blocker) to reduce preload2. digoxin to increase capacity of muscle contract 3. ACE inhibitors and A-blocker to reduce afterload</p>
<p>management of chronic heart failure</p>
<p>1. ACE inhibitors2. diuretics and nitrates3. B-blockers4. ACE inhibitor and ARB</p>
<p>What are the adaptive response when in cardiac failure?</p>
<p>1. Cardiac dilatation - CO increases as length of muscle fibre is increased2. Sympathetic drive - Increased preload, contractility, afterload3. Renin angiotensin system - Aldosterone causes sodium retention - Angiotensin II causes peripheral vasoconstriction (increase preload, contractility, afterload = increase O2 demand and eventual decompensation)</p>
<p>Principles of treatment of cardiac failure</p>
<p>1. Reduction of preload - Diuretics (decrease blood volume) - Nitrates - a-blocker (venodilation)2. Increased capacity of the myocardium to contract - Digoxin3. Reduction of afterload - ACE inhibitors (vasodilation) - a-blocker (vasodilation)4. Counteract activation of sympathetic nervous system - B-blocker5. Counteract activation of RAAS - ACE inhibitors6. Management of chronic heart failure - ACE inhibitors - Diuretics - Beta blockers </p>
<p>Underlying cause of cardiac arrhythmias</p>
<p>1. Sodium channel blockade2. Beta adrenergic receptor blockade3. Prolong repolarisation4. Calcium channel blockade</p>
<p>Treatment of cardiac arrhythmias</p>
<p>1. adenosine2. digitalis glycosides</p>
<p>what is variant angina?</p>
<p>vasospasm and temporary reduction of coronary blood flow</p>
<p>define stable angina</p>
<p>- chronic narrowing of coronary arteries due to inadequate blood flow</p>
<p>define unstable angina</p>
<p>- formation and dissolution blood clot (thrombosis) in coronary artery- coronary blood flow reduced causing decreased O2 supply - MI if clot completely occludes coronary arteries</p>
<p>Principles of treatment of angina</p>
<p>1. Dilation of arteries and veins - Calcium channel blocker - Nitrates2. Reduction of heart rate and contractility - Beta blocker - Clacium channel blocker3. Prevention of thrombus formation - Anticoagulant - Anti platelet drugs</p>
<p>Principles of treatment myocardial infarction</p>
<p>1. Vasodilation - Nitrates - ACE inhibitors - ARBs2. Cardiac depression - beta blockers 3. Antiarrhythmics4. Thrombolysis (primary) - Plasminogen activators5. Analgesics - morphine6. Anti thrombotics (secondary) - Anticoagulant - Anti platelet drugs</p>
