physio ex6 test 2
People with weakened hearts need to allow max time for venous return and increased SV and
would benefit from - ANSincreased force of contraction and decreased heart rate
The ion that had the most pronounced effect on heart rate was - ANSpotassium.
Where in the cardiac muscle cell is most of the sodium normally found? - ANSoutside the cell
Which of the following is true of epinephrine? - ANSIt increases the heart rate and mimics the
sympathetic nervous system.
Norepinephrine affects the heart rate by - ANSincreasing the rate of depolarization and
increasing the frequency of action potentials.
The cardiac muscle is capable of which of the following? - ANSautorhythmicity
Phase 2 of the cardiac action potential, when the calcium channels remain open and potassium
channels are closed, is called the - ANSplateau phase
Which of the following is true of the cardiac action potential? - ANSThe cardiac action potential
is longer than the skeletal muscle action potential.
The main anatomical difference between the frog heart and the human heart is that the frog
heart has - ANSa single, fused ventricle.
Which of the following statements about contractile activity is true? - ANSThe smaller waves
represent the contraction of the atria
During which portion of the cardiac muscle contraction is it possible to induce an extrasystole -
ANSduring relaxation
The amplitude of the ventricular systole did not change with the more frequent stimulation
because - ANSa new contraction could not begin until the relaxation phase
Which of the following do you think contribute to the inability of cardiac muscle to be tetanized? -
ANSthe long refractory period of the cardiac action potential
Given the function of the heart, why is it important that cardiac muscle cannot reach tetanus? -
ANSThe ventricles must contract and relax fully with each beat to pump blood.
An extrasystole corresponds to - ANSan extra ventricular contraction
People with weakened hearts need to allow max time for venous return and increased SV and
would benefit from - ANSincreased force of contraction and decreased heart rate
The ion that had the most pronounced effect on heart rate was - ANSpotassium.
Where in the cardiac muscle cell is most of the sodium normally found? - ANSoutside the cell
Which of the following is true of epinephrine? - ANSIt increases the heart rate and mimics the
sympathetic nervous system.
Norepinephrine affects the heart rate by - ANSincreasing the rate of depolarization and
increasing the frequency of action potentials.
The cardiac muscle is capable of which of the following? - ANSautorhythmicity
Phase 2 of the cardiac action potential, when the calcium channels remain open and potassium
channels are closed, is called the - ANSplateau phase
Which of the following is true of the cardiac action potential? - ANSThe cardiac action potential
is longer than the skeletal muscle action potential.
The main anatomical difference between the frog heart and the human heart is that the frog
heart has - ANSa single, fused ventricle.
Which of the following statements about contractile activity is true? - ANSThe smaller waves
represent the contraction of the atria
During which portion of the cardiac muscle contraction is it possible to induce an extrasystole -
ANSduring relaxation
The amplitude of the ventricular systole did not change with the more frequent stimulation
because - ANSa new contraction could not begin until the relaxation phase
Which of the following do you think contribute to the inability of cardiac muscle to be tetanized? -
ANSthe long refractory period of the cardiac action potential
Given the function of the heart, why is it important that cardiac muscle cannot reach tetanus? -
ANSThe ventricles must contract and relax fully with each beat to pump blood.
An extrasystole corresponds to - ANSan extra ventricular contraction
