Critical care exam 2 STUDY GUIDE NOTES 2021

Critical care exam 2 STUDY GUIDE NOTES 2021

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ANA: The sympathetic nervous system releases norepinephrine, which has alpha- and betaadrenergic effects. Alpha-adrenergic effects cause arterial vasoconstriction. Beta-adrenergic effects increase s... inus node discharge (positive chronotropic), increase the force of contraction (positive inotropic), and accelerate the AV conduction time (positive dromotropic). The parasympathetic nervous system releases acetylcholine through stimulation of the vagus nerve. It causes a decrease in the sinus node discharge and slows conduction through the AV node. The blood supply to the myocardium is derived from the coronary arteries NOT ON EXAM S1: best heard at the apex of the heart (fifth intercostal space, left midclavicular line) and represents the beginning of ventricular systole. S2: It has been described as “dub” and is caused by closure of the pulmonic and aortic valves. It is best heard at the second intercostal space at the left or right sternal border and represents the beginning of ventricular diastole. The first and second heart sounds are best heard with the diaphragm of the stethoscope. S3: S3 or ventricular or protodiastolic gallop, is a normal variant in young adults, but usually abnormal the older adult. The sound is caused by rapid left ventricular filling and m [Show More]