NSE 13A/B Chapter Notes - Chapter 20: Vasodilation, Vagal Tone, Suprasternal Notch
27 Mar 2017
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Cardiovascular system: heart (pump), blood vessels (pulmonary and systemic circulation) Precordium: area on anterior chest overlying heart and great vessels (major arteries and veins connected to the heart, above the heart) Contraction: apex beats against chest wall, producing apical impulse. Av valves ope(cid:374) duri(cid:374)g heart"s filli(cid:374)g phase (diastole) ventricles fil with blood. Pumping phase (systole) av valves close to prevent regurgitation of blood back up into atria. Cardiac cycle: rhythmic ovement of blood through the heart, diastole: ventricles relax and fill with blood, systole: heart contractions, blood pumped from ventricles and fills pulmonary and systemic arteries. Systole: volume of blood raises ventricle pressure, pressure is now higher than atria, mitral and tricuspid valves close, ventricular walls contract against closed system builds pressure inside ventricles. Isometric contraction: pressure exceeds aorta pressure aortic valve opens and blood ejects, pressure drops therefore some blood rushes back in aortic valve closes.
