NR507 Advanced Pathophysiology

How does blood flow through the heart? - Deoxygenated venous blood → Sup. Vena Cava → Right Atrium →Tricuspid (AV) →Empties into R. Ventricle (& it contracts) → Blood ejected through Pulmonary Valve → Pulmonary Artery → Lungs to be Oxygenated → Pulmonary Veins → L. Atrium → Mitral (AV) → L. Ventricle (pumps with each contraction) → Aortic Valve → Aorta → Body What is systole? - Contraction of the heart which pumps blood Diastole - Relaxation of the heart What produces S1 and S2 sound? - closing of the heart valves What produces S1? - The mitral and tricuspid valves which close in systole What produces S2 sound? - The closing of the aortic and pulmonic valves in diastole What is cardiac output? - the volume of blood pumped out by each ventricle per minute What is stroke volume? - amount of blood pumped out by each ventricle with contraction What determines cardiac output? - stroke volume and heart rate What is preload? - the degree of stretch on the heart before it contracts, related to ventricular filling, end diastolic pressure, amount of blood entering the ventricle during diastole What is afterload? - resistance left ventricle must overcome to circulate blood What is contractility? - Normal ability of muscle to contract at a given force for a given stretch. It is independent of preload/afterload Will sustained tachycardia result in increased or decreased stroke volume? - Decreased What conditions can result in decreased contractility? - Ischemia, acidosis, cardiomyopathy What can cause increase afterload? - HTN, pulmonary disease, damage to the aortic valve What has the most immediate effect on afterload? - HTN Why would hemorrhaging cause decreased afterload? - Decreased volume of blood creates less resistance What does increased preload do to stroke volume? - Increases stroke volume, over time the body will be unable to compensate however What can cause a decreased preload? - Hemorrhage, dehydration...anything that causes reduced blood volume