Ch 19 SG.docx - R rationale Assessment Ch 19 Heart and Neck...

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R: rationale Assessment Ch. 19 Heart and Neck Vessels Position and Surface Landmarks CV system consists of heart and blood vessels Precordium: area on anterior chest directly overlying the heart and great vessels Heart: 2 nd -5 th intercostal space Blood vessels are arranged in 2 continuous loops o Pulmonary circulation and systemic circulation Top of heart is base and bottom of heart is apex Great vessels are bunched up above the base Superior and inferior vena cava: return unoxygenated blood to right side of heart Pulmonary artery: leaves right ventricle and carries venous blood to lungs Pulmonary veins: returns freshly oxygenated blood to left side of heart and aorta carries it out of the body Heart Wall, Chambers, and Valves Heart wall has numerous layers: o Pericardium: double walled sac that surrounds and protects the heart o Myocardium: muscular wall of heart and does the pumping o Endocardium: thin layer of the inner surface of heart chambers and valves Atrium holds the blood and ventricles pump the blood Atrioventricular valves: o Tricuspid: right AV valve o Bicuspid/Mitral: left AV valve o Open during filling phase (diastole) and close during systole to prevent backflow Semilunar valves: o Pulmonic valve: right side o Aortic valve: left side o Open during pumping (systole) Direction of Blood Flow superior/inferior vena cava drains blood to right atrium right atrium blood travels through tricuspid valve to RV RV blood goes through pulmonic valve to pulmonary artery Pulmonary artery delivers unoxygenated blood to lungs Lungs oxygenate blood Pulmonary veins carries oxygenated blood to LA LA blood goes through mitral valve to LV LV blood goes through aortic valve in to aorta Aorta delivers oxygenated blood to rest of body Blood flows from area of high pressure to lower pressure Cardiac Cycle: Cardiac cycle: rhythmic movement of blood through the heart Diastole: o Ventricles are relaxed and fill with blood o AV valves are open o Pressure in the atria is higher than in the ventricles which causes blood to pour rapidly into ventricles o Early/protodiastolic filling: first passive filling phase o Presystolic/atrial systole: active filling phase End of diastole, the atria contracts and pushes last amount of blood into ventricles o 2/3 of cardiac cycle Systole: o Heart contraction o Ventricular pressure is higher in ventricles now than atria o AV valves shut to prevent backflow S1 sound (first heart sound) o Ventricular walls contract building up pressure which then exceeds pressure in aorta Aortic valve opens and blood is ejected rapidly o SL valves close S2 sound (second heart sound) Diastole again: o Isometric/Isovolumic relaxation: all 4 valves are close and ventricle relaxed o Atrial pressure is now higher that the relaxed ventricular pressure Events in right and left side: o Pressures in the right side of heart are much lower than

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