7. If your instructor asked you to explain why the myocardium is thicker in the left ventricle than it is in the right ventricle, which of the following would you most likely say? a. The right ventricle has to pump harder to overcome the high resistance required to pump blood into the long pulmonary circuit, whereas the left ventricle does not need to generate as much pressure since the systemic circuit is shorter and provides less resistance. b. The right ventricle has to pump harder to overcome the high resistance required to pump blood into the long systemic circuit, whereas the left ventricle does not need to generate as much pressure since the pulmonary circuit is shorter and provides less resistance. c. The left ventricle has to pump harder to overcome the high resistance required to pump blood into the long systemic circuit, whereas the right ventricle does not need to generate as much pressure since the pulmonary circuit is shorter and provides less resistance. d. The left ventricle has to pump harder to overcome the high resistance required to pump blood into the long pulmonary circuit, whereas the right ventricle does not need to generate as much pressure since the systemic circuit is shorter and provides less resistance.

39. The onset of Ventricular diastole is associated with: A. the closing of the aortic valve B. the ejection of blood from the ventricles C. the opening of the atrio-ventricular (AV) valves D. the first heart sound

1. You should be able to distinguish two heart sounds.  The first sound is when the ventricle begins contracting (ventricular systole) the atrioventricular valves snap shut.  This closing produces a low-pitched sound, the "lub" sound. The atrioventricular valves close when the ventricles contract due to pressure coming from the blood in the: Group of answer choices veins ventricles arteries atria   2.  The "lub" sound is accompanied by the pulmonary and aortic (semilunar) valves opening. This, too, happens when the ventricles contract. These valves open due to pressure of the blood coming from the: Group of answer choices atria ventricles arteries veins   3. The second sound you hear in the heartbeat is when the ventricles begin to relax (diastole). The closing of the pulmonary and aortic (semilunar) valves produces a sound, the "dub" sound. These valves close when the ventricles relax due to the pressure of the blood coming from the: Group of answer choices atria…

2. How is an action potential in a contractile cardiac cell different from action potential in a pacemaker cell? (Write the phases and the channels involved for each phase).