NURS 5315 Module 5 Exam With Complete Solution

NUR S 5315 M odule 5 Exam W ith Comp lete Solution Cardia structure/blood flow - Answer The right atrium receives deoxygenated blood f rom the body. The blood travels from the right atrium, through the tricuspid va lve to the right ventricle. From the right ventricle the blood travels through the pulmonic valve, into th e pulmonary artery (this is the only artery in the body which carries deoxygenated blood), into the lungs, where it goes to the alveoli and gas exchange occurs. The oxygen ated blood then enters the pulmonary vein and is delivered to the left atrium. From the left atrium it travels through the mitral valve into the left ventricle. From the left ventricle the blood travels through the aortic valve into the aorta Fetal circulation - Answer The umbilical vein receives oxygenated blood from the placenta. The umbilical vein connects to the hepatic circulation but also connects to th e inferior vena cava by the ductus venosus. The ductus venosus allows the oxygen- rich blood to enter the inferior vena cava and some blood does enter the hepatic circu lation. From the inferior vena cava, the blood is emptied into the right atrium. The mo st oxygenated blood in the right atrium is shunted through the foramen ovale (this is an opening between the right and left atria) into the left atrium. The blood then enters the left ventricle and is pumped out to the head and the rest of the body. The deoxygenated blood also enters the right atrium just as the oxygenated blood does. There are two streams that help to keep the blood separate. Sixty percent of the blood in the ri ght atrium (which is oxygenated blood) will be moved forward as described above. The remaining 40% of the blood is mixed blood (oxygenated and deoxygenated) and will move from the right atrium, to the right ventricle, and into the pulmonary a rtery. From the pulmonary artery it will pass through the patent ductus arteriosus (which is a connection between the pulmonary artery and the aorta) into the aorta. The a orta will connect with the umbilical artery, where the blood will go back to the placenta to exchange gas, get rid of waste products and pick up nutrients. The right side of the heart has the higher pressure prior to birth. After birth, this changes with the neona te's first breath and the left side of the heart becomes the one with the higher pressu re. Factors which increase contraction - Answer **Catecholamines-increase activity of the calcium pump in the sarcoplasmic reticulum; therefore it increases the release of calcium from the SR**Increases in intracellular calcium**Decreased extracellular sodium-decreases the activity of the Na/Ca exchanger**Digitalis-blocks the Na/K pump which increases intracellular Na, decreases the activity of the NA/Ca exchanger, and increases intracellular Ca Factors which decrease contraction - Answer **Beta blockers-block the effects of the catecholamines**heart failure with systolic dysfunction**acidosis**hypoxia/hypercapnia **nondihydropyridine calcium channel blockers Cardiac output (CO) - Answer Amount of blood pushed from the left ventricle in 1 minutes. HR X STROKE VOLUME = CO. Normal output is 5L/minute Stroke Volume - Answer Amount of blood ejected by the ventricle for each cardiac cycle. Highly dependent on the force of contraction. Contraction is dependent upon amount of preload, stimulation by endogenous positive inotropic agents such as epi and norepi, presence of negative inotropic agents and adequacy of myocardial oxygenatio n Ejection fraction (EF) - Answer Percentage of blood which is ejected from the ventricle with each contraction. Calculated by dividing the stroke volume by the end diastolic volume. Normal EF is 55-65%. EF decreases with systolic heart failure but not in diastolic heart failure Preload - Answer Made up of end diastolic volume and end diastolic pressure. Dependent upon the amount of venous return to the heart and the amoun t of blood left in the left ventricle at the end of systole. Increased preload can cause heart failu re from a decline in stroke volume and a back up into pulmonary circulation Afterload - Answer Resistance that the ventricle pushes against to contract. This includes aortic pressure and systemic vascular resistance. High afterload increases the work of the ventricle and results in hypertrophy. A low afterload enables the hea rt to contract faster Diltiazem and verapamil - Answer non-dihydropyridine calcium channel blockers. They inhibit the influx of calcium into the myocardium. This decreases intracellular calcium concentration which in turn decreases myocardial tension and contractility. They have negative inotropic effects. As such these medications should be avoided in persons with systolic heart failure. Dobuamine - Answer Stimulates the beta 1 receptors in the myocardium and improv es contractility and increases heart rate Epinephrine - Answer Primarily stimulates beta 1 receptors of the heart which results in an increase in myocardial contractility and heart rate. Also effects beta 2 and alpha 1 receptors which cancel each other out and does not change vascular tone. In high doses alpha 1 overrides beta 2 which causes vasocontriction and increased systemic vascular resistance while still enhancing contractility and cardiac output Norepinephrine - Answer Stimulates both beta 1 and alpha 1 receptors. This incrases myocardial contractility and causes vasoconstriction. Result in increase in cardiac output and blood pressure