exam 2 multiple answers A&P II 2023 verified to pass

exam 2 multiple answers A&P IICheck all that are characteristics of cardiac muscle. A. Cells are long and cylindrical. B. Cells are short and branching. C. Cells have multiple nuclei at the periphery of the cell. D. Cells have one or two nuclei in the center of the cell E. They are composed of thick and thin filaments. F. The functional contractile unit is the sarcomere. - correct answer B, D, E, F Check all that occur during ventricular systole A. The AV valves open to allow blood to enter the ventricles from the atria. B. The semilunar valves remain closed throughout systole to prevent backflow of blood into the ventricles. C. The semilunar valves open to allow blood to flow into the large arteries. D. The AV valves close to prevent backflow of blood into the atria. - correct answer C, D Check all of the ways in which the heart chambers are involved in pulmonary circulation. A. Oxygenated blood enters the left atrium. B. Oxygenated blood enters the right atrium. C. The right ventricle pumps deoxygenated blood to the lungs. D. The left ventricle pumps deoxygenated blood to the lungs. E. Pulmonary veins pass blood into the left atrium whereas pulmonary arteries carry blood away from the right ventricle. F. Pulmonary veins pass blood into the right atrium whereas pulmonary arteries carry blood away from the left ventricle. - correct answer A, C, E T/F The resting membrane potential of cardiac muscle cells depends on a low permeability of the plasma membrane to sodium and potassium and a higher permeability to calcium - correct answer False T/F Action potentials in cardiac muscle last longer than those in skeletal muscle. - correct answer True T/F In skeletal muscle there is a plateau phase, a period of slow repolarization, that is not found in cardiac muscle - correct answer False What are the individual ion contributions to the resting membrane potential (RMP) of the SA nodal cells? Check all that apply. A. Greater concentration of Na+ outside the cell B. No Na+/K+ pump C. Greater concentration of K+ inside the cell D. Calcium (Ca2+) gradient with more calcium outside the cell - correct answer A, C, D T/F SA nodal cells are unique in that they exhibit autorhythmicity, meaning they are capable of depolarizing and firing an action potential spontaneously without any external influence. - correct answer True What are the series of events in the SA nodal cells that directly cause autorhythmic contraction of cardiac muscle cells? Check all that apply. A. Fast voltage-gated sodium channels open, causing depolarization after threshold has been reached. B. Slow voltage-gated sodium channels open, causing a slow depolarization to threshold. C. Fast voltage-gated calcium channels open, causing depolarization after threshold has been reached. D. Voltage-gated potassium channels open, causing repolarization. - correct answer B, C, D What is the correct order of mechanical events associated with cardiac muscle contraction? - correct answer Calcium entry into the sarcoplasm, calcium binds to troponin, muscle contracts, closing of calcium channels, calcium released from troponin, muscle relaxes T/F The refractory period of skeletal muscle is longer than for cardiac muscle. - correct answer False T/F Cardiac output (CO) is equivalent to heart rate (HR) multiplied by stroke volume (SV). - correct answer True