Which of the following is not true about Ventricular cardiac action potentials? O A. Action potentials arise from current flow across membranes. O B. Current is carried by neutral ions. O C. Action potentials fire in an all-or-none fashion. D. A stimulus usually initiates the action potential in healthy cells. E. Potassium is the dominant current during the diastolic interval.

Cardiac output measures blood ejected from a. both atria each minute b. each ventricle each minute c. both ventricles each minute d. each atrium each minute e. each atrium each beat

The entry of calcium into a ventricular muscle cell helps to maintain depolarization of the membrane during the plateau phase of the action potential, but this calcium also performs what other function?

Which formula correctly expresses cardiac output (O) through the end-diastolic volume of the ventricle (V), ejection fraction (E) and heartbeat rate (R)?           O = VER       O = VE/R           O = VR/E       O = RE/V

The function of the right and left bundle branches is to _____.   A rapidly transmit action potentials along the interventricular septum   B contract forcefully to eject blood from the ventricle   C spontaneously depolarize to start a second action potential in the ventricles   D delay action potentials so that the atria have time to contact before the ventricles

Which of the following would NOT result from an increase in sympathetic stimulation of the heart?   A increased force of ventricular contraction   B increased calcium concentration in the fluid surrounding the actin and myosin during contraction   C increased heart rate   D increased number of motor units activated   E increased cardiac output

the herbal supplements bitter orange, also known as synephrine, mimics the effects of neurotransmitters on the SNS on the heart and blood vessels serving the abdominal viscera and skin. what effect do you think this would have on the blood pressure? Considering this, do you think this drug should be given to people with hypertension (high blood pressure)?

The role of calcium currents in cardiac contractile cells is to .  The role of calcium currents in cardiac conductive cells is to .    Choose between: release neurotransmitter, bring the membrane potential to threshold, initiate action potential, prolong action potential, terminate action potential

During which phase of the cardiac cycle do the ventricles begin to contract while the semilunar valves remain closed ? Group of answer choices Isovolumetric contraction Ventricular ejection Ventricular filling

isovolumetric contraction isovolumetric relaxation ventricular filling ventricular ejection closed rises S1 drops depolarize S2 The first phase of the cardiac cycle is . This is when a lot of blood is in the atria, which causes atrial pressure to be higher than the ventricles. The atrioventricular valves open, and blood moves from the atria to the ventricles. At the end of this phase, the atria contract to maintain pressure and blood flow into the ventricles. As blood leaves the atria, the pressure in the atria As blood enters the ventricles, the pressure in the ventricles Towards the end of this phase, the pressure in the ventricles will exceed the pressure in the atria. At this point, the heart enters the second phase of the cardiac cycle: At this point, the AV valves shut, and we hear . The atria repolarize and the ventricles (due to the QRS complex of the ECG), causing ventricular contraction. Although contracting, it is not yet moving blood into the arteries. All 4 heart valves…