Which of the Following is not Important in Preventing Backflow of Blood

2. Which of the following is not important in preventing backflow of blood? 1. chordae tendineae 2. papillary muscles 3. AV valves 4. endocardium 3 . Which valve separates the left atrium from the left ventricle? 1. mitral 2. tricuspid 3. pulmonary 4. aortic 4 . Which of the following lists the valves in the order through which the blood flows from the vena cava through the heart? 1. tricuspid, pulmonary semilunar, bicuspid, aortic semilunar 2. mitral, pulmonary semilunar, bicuspid, aortic semilunar 3. aortic semilunar, pulmonary semilunar, tricuspid, bicuspid 4. bicuspid, aortic semilunar, tricuspid, pulmonary semilunar 5 . Which chamber initially receives blood from the systemic circuit? 1. left atrium 2. left ventricle 3. right atrium 4. right ventricle 6 . The ________ layer secretes chemicals that help to regulate ionic environments and strength of contraction and serve as powerful vasoconstrictors. 1. pericardial sac 2. endocardium 3. myocardium 4. epicardium 7 . The myocardium would be the thickest in the ________. 1. left atrium 2. left ventricle 3. right atrium 4. right ventricle 8 . In which septum is it normal to find openings in the adult? 1. interatrial septum 2. interventricular septum 3. atrioventricular septum 4. all of the above 9 . Which of the following is unique to cardiac muscle cells? 1. Only cardiac muscle contains a sarcoplasmic reticulum. 2. Only cardiac muscle has gap junctions. 3. Only cardiac muscle is capable of autorhythmicity 4. Only cardiac muscle has a high concentration of mitochondria. 10 . The influx of which ion accounts for the plateau phase? 1. sodium 2. potassium 3. chloride 4. calcium 11 . Which portion of the ECG corresponds to repolarization of the atria? 1. P wave 2. QRS complex 3. T wave 4. none of the above: atrial repolarization is masked by ventricular depolarization 12 . Which component of the heart conduction system would have the slowest rate of firing? 1. atrioventricular node 2. atrioventricular bundle 3. bundle branches 4. Purkinje fibers 13 . The cardiac cycle consists of a distinct relaxation and contraction phase. Which term is typically used to refer ventricular contraction while no blood is being ejected? 1. systole 2. diastole 3. quiescent 4. isovolumic contraction 14 . Most blood enters the ventricle during ________. 1. atrial systole 2. atrial diastole 3. ventricular systole 4. isovolumic contraction 15 . The first heart sound represents which portion of the cardiac cycle? 1. atrial systole 2. ventricular systole 3. closing of the atrioventricular valves 4. closing of the semilunar valves 16 . Ventricular relaxation immediately follows ________. 1. atrial depolarization 2. ventricular repolarization 3. ventricular depolarization 4. atrial repolarization 17 . The force the heart must overcome to pump blood is known as ________. 1. 2. 3. 4. preload afterload cardiac output stroke volume 18 . The cardiovascular centers are located in which area of the brain? 1. medulla oblongata 2. pons 3. mesencephalon (midbrain) 4. cerebrum 19 . In a healthy young adult, what happens to cardiac output when heart rate increases above 160 bpm? 1. It increases. 2. It decreases. 3. It remains constant. 4. There is no way to predict. 20 . What happens to preload when there is venous constriction in the veins? 1. It increases. 2. It decreases. 3. It remains constant. 4. There is no way to predict. 21 . Which of the following is a positive inotrope? 1. Na 2. K + + 3. Ca 2+ + 4. both Na and K + 22 . The earliest organ to form and begin function within the developing human is the ________. 1. brain 2. stomach 3. lungs 4. heart 23 . Of the three germ layers that give rise to all adult tissues and organs, which gives rise to the heart? 1. ectoderm 2. endoderm 3. mesoderm 4. placenta 24 . The two tubes that eventually fuse to form the heart are referred to as the ________. 1. primitive heart tubes 2. endocardial tubes 3. cardiogenic region 4. cardiogenic tubes 25 . Which primitive area of the heart will give rise to the right ventricle? 1. bulbus cordis 2. primitive ventricle 3. sinus venosus 4. truncus arteriosus 26 . The pulmonary trunk and aorta are derived from which primitive heart structure? 1. bulbus cordis 2. primitive ventricle 3. sinus venosus 4. truncus arteriosus