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41 Cards in this Set
- Front
- Back
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Name the major coronary arteries.
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Right coronary artery
Left coronary artery Circumflex artery Left anterior descending artery |
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What is the leading cause of death in the US?
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Heart disease.
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What is automaticity of the heart?
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The ability to beat on its own.
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What ions are part of depolarization and how do they work?
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NA rushes into the cell whil K migrates outside the cell.
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What meds directly effect cardiac action potentials?
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nifidipine, cardizem, quinidine, and pronestyl.
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What happens when Ca moves out of a cardiac cell?
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Contraction decreases and muscles relax.
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What is a drug that blocks sodium channels?
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Lidocaine.
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What drug blocks potassium channels?
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Amiodarone.
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What drug blocks calcium channels?
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Diltiazem.
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What is phase 0 of the cardiac action potential?
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Depolarization.
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What is phase 1 of the cardiac action potential?
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Repolarization.
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What is phase 2 of the cardiac action potential?
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Plateau phase of repolarization.
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What is phase 3 of the cardiac action potential?
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End of repolarization.
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What is phase 4 of the cardiac action potential?
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Resting phase.
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What is absolute refractory period?
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A period of time when the heart is already beating and it cannot accept an additional beat at this time.
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Why would it be desirable to give drugs that extend the refractory period?
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No additional beats can be initiated during this time so by extending this period, the heart rate can be slowed.
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What drugs extend the refractory period?
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Digoxin and cardizem.
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Define diastole.
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Atria and ventricles are relaxed and filling with blood.
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Define atrial kick.
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The contraction of the atria.
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Define systole.
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The atria and ventricles are emptying and the blood is being propelled out to the pulmonary and systemic circulation.
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What 4 factors affect cardiac output?
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1. Preload
2. Afterload 3. Heart rate 4. Contractility |
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Define preload.
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Pressure generated in the ventricle at the very end of diastole.
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What happens in a healthy heart if preload is increased.
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Stroke volume increases and contraction increases.
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Define afterload.
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The resistance or impedence to ejection of blood from the ventricle.
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What is the result of increased afterload?
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Decreased cardiac output.
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What is the result of decreased afterload?
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Increased cardiac output.
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Define contractility.
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The inherent ability of the muscle fibers to shorten and contract.
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What 3 major factors effect contractility?
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1. Increased preload = increased contractility.
2. SNS = increased afterload. 3. Adequacy of myocardial oxygen supply. |
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Define inotropic.
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Factors affecting the force of contraction.
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Define chronotropic.
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Factors affecting the rate of contraction.
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What happens in a healthy heart as metabolic needs increase?
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HR increases and stroke volume and cardiac output increase.
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What rate indicates tachycardia?
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HR > 100.
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What are the consequences of tachycardia in a diseased heart?
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Decreased filling time leads to decreased stroke volume which leads to decreased cardiac output.
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When do coronary arteries fill?
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During diastole.
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Where are baroreceoptors located?
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In the carotid sinus and aortic arches.
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What is the function of the baroreceptors?
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They responsd to pressure on the vessels and trigger the SNS or PSNS as needed.
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How does the PSNS effect the heart?
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It decreases the HR, cecrease the force of contraction, thus decreasing BP.
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What drug is given to block the vagal effects of the PSNS?
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Atropine.
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List some vagal manuevers.
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Carotid massage, gagging, and bearing down.
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How does the SNS effect the heart?
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Increase HR, increase contraction, and increase BP.
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Which beta receptors are found in the heart?
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Beta-1.
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