Multiple Choice Questions

The repolarization of cardiac muscle is due to
  • Potassium
  • Carry blood away from the heart
  • the start of ventricular systole
  • Potassium exiting the cell
How would a decrease in blood volume affect both stroke volume and cardiac output?
  • Contractibility ***increased sympathetic activity increases heart contractility. This causes cardiac fibers to contract more forcefully at all levels of preload. Regardless of end diastolic volume, this mechanism increases stroke volume by reducing end systolic volume.
  • So blood is forced upward, toward the semilunar valves +++++Beginning contraction at the apex causes blood to be forced upward, through the semilunar valves, and into the aorta and pulmonary trunk. This makes ventricular ejection more efficient, much like squeezing a tube of toothpaste up from the bottom is more efficient at dispensing the toothpaste than is squeezing from the top.
  • A vessel that carries blood away from the heart
  • a decreased blood volume would decrease the end diastolic volume, thus lowering the stroke volume. Although this would initially lead to a decrease in the cardiac output, heart rate would increase because of increased activity of the sympathetic nervous system in a effort to maintain cardiac output.
What is an advantage to the longer duration of cardiac action potential compared to the skeletal muscle action potential?
  • The longer duration prevents tetanic contraction, which ensures that the heart chambers will relax and refill with blood before the next contraction
  • a decreased blood volume would decrease the end diastolic volume, thus lowering the stroke volume. Although this would initially lead to a decrease in the cardiac output, heart rate would increase because of increased activity of the sympathetic nervous system in a effort to maintain cardiac output.
  • Blood pressure decreases, because of the effects of friction between the vessels walls and the moving blood.
  • Closing of the atrioventricular valvesThe QRS complex is a recording of ventricular depolarization. This depolarization begins just prior to the ventricular contraction it initiates. As the ventricles contract, the increase in ventricular pressure closes the atrioventricular valves, beginning isovolumetric contraction. As ventricular pressure increases above the corresponding blood vessel, only then do the semilunar valves open, initiating ventricular ejection..
Which blood vessels return blood to the heart?
  • End diastolic volume and sympathetic nervous system stimulation.
  • Because the heart establishes a pressure gradient
  • Veins
  • Vasodilation
The anatomy of the intrinsic conduction system causes contraction of the ventricles to begin at the apex and move superiorly. why is this important?
  • Closing of the atrioventricular valvesThe QRS complex is a recording of ventricular depolarization. This depolarization begins just prior to the ventricular contraction it initiates. As the ventricles contract, the increase in ventricular pressure closes the atrioventricular valves, beginning isovolumetric contraction. As ventricular pressure increases above the corresponding blood vessel, only then do the semilunar valves open, initiating ventricular ejection..
  • a decreased blood volume would decrease the end diastolic volume, thus lowering the stroke volume. Although this would initially lead to a decrease in the cardiac output, heart rate would increase because of increased activity of the sympathetic nervous system in a effort to maintain cardiac output.
  • closing of the semilunar valvesclosing of the atrioventricular valves++++Heart sounds are an extremely helpful diagnostic tool that is not invasive. The first heart sound, often described as a lubb, corresponds to the closing of the atrioventricular valves. The second heart sound is a sharper and crisper dupp that corresponds to the closing of the semilunar valves. Consequently, the two heart sounds mark the beginning and the end of ventricular systole.
  • So blood is forced upward, toward the semilunar valves +++++Beginning contraction at the apex causes blood to be forced upward, through the semilunar valves, and into the aorta and pulmonary trunk. This makes ventricular ejection more efficient, much like squeezing a tube of toothpaste up from the bottom is more efficient at dispensing the toothpaste than is squeezing from the top.
Along with nutrients, hormones, water, and gases, the cardiovascular system also transports
  • heat, immune cells, and cellular wastes
  • The atrioventricular valves and semilunar valves are both closed.
  • the start of ventricular systole
  • Ventricular ejection
Calcium ions are removed from the sarcoplasm of the cardiac cell by the action of sarcoplasmic reticulum (SR) Ca2+-ATPase pump and which other mechanism?
  • Sodium- calcium exchanger on the sarcolemma
  • Sodium and calcium
  • Friction causes a loss of energy
  • heat, immune cells, and cellular wastes
Most of the oxygen exiting the blood and entering the tissues does so from the
  • Vasodilation
  • Atrial systole
  • Capillaries
  • Ventricular ejection
The electrocardiogram represents ______.
  • The electrical activity of all of the cardiac muscle cells
  • A vessel that carries blood away from the heart
  • the start of ventricular systole
  • The atrioventricular valves and semilunar valves are both closed.
The beginning of the QRS complex of the electrocardiogram (ECG) immediately precedes which of the following events?
  • closing of the semilunar valvesclosing of the atrioventricular valves++++Heart sounds are an extremely helpful diagnostic tool that is not invasive. The first heart sound, often described as a lubb, corresponds to the closing of the atrioventricular valves. The second heart sound is a sharper and crisper dupp that corresponds to the closing of the semilunar valves. Consequently, the two heart sounds mark the beginning and the end of ventricular systole.
  • Closing of the atrioventricular valvesThe QRS complex is a recording of ventricular depolarization. This depolarization begins just prior to the ventricular contraction it initiates. As the ventricles contract, the increase in ventricular pressure closes the atrioventricular valves, beginning isovolumetric contraction. As ventricular pressure increases above the corresponding blood vessel, only then do the semilunar valves open, initiating ventricular ejection..
  • Contractibility ***increased sympathetic activity increases heart contractility. This causes cardiac fibers to contract more forcefully at all levels of preload. Regardless of end diastolic volume, this mechanism increases stroke volume by reducing end systolic volume.
  • So blood is forced upward, toward the semilunar valves +++++Beginning contraction at the apex causes blood to be forced upward, through the semilunar valves, and into the aorta and pulmonary trunk. This makes ventricular ejection more efficient, much like squeezing a tube of toothpaste up from the bottom is more efficient at dispensing the toothpaste than is squeezing from the top.
Which of the following can be heard with a stethoscope most easily?
  • A vessel that carries blood away from the heart
  • Closing of the atrioventricular valvesThe QRS complex is a recording of ventricular depolarization. This depolarization begins just prior to the ventricular contraction it initiates. As the ventricles contract, the increase in ventricular pressure closes the atrioventricular valves, beginning isovolumetric contraction. As ventricular pressure increases above the corresponding blood vessel, only then do the semilunar valves open, initiating ventricular ejection..
  • The sum of the electrical activity of all cells of the body.
  • closing of the semilunar valvesclosing of the atrioventricular valves++++Heart sounds are an extremely helpful diagnostic tool that is not invasive. The first heart sound, often described as a lubb, corresponds to the closing of the atrioventricular valves. The second heart sound is a sharper and crisper dupp that corresponds to the closing of the semilunar valves. Consequently, the two heart sounds mark the beginning and the end of ventricular systole.
Arteries are most accurately defined as blood vessels that
  • Wave summation and fused tetanus
  • Carry blood away from the heart
  • Because the heart establishes a pressure gradient
  • Friction causes a loss of energy
The heart sounds associated with the atrioventricular valves closing occur at __________.
  • passive blood flow from the atrium
  • the start of ventricular systole
  • Atrial systole
  • Carry blood away from the heart
By what mechanism would an increase in venous return increase stroke volume?
  • End diastolic volume and sympathetic nervous system stimulation.
  • an increase in venous return increases the end diastolic volume. The fibers are stretched more, resulting in an increase in the force of contraction ( preload, or the Frank-starling mechanism)
  • Blood pressure decreases, because of the effects of friction between the vessels walls and the moving blood.
  • a decreased blood volume would decrease the end diastolic volume, thus lowering the stroke volume. Although this would initially lead to a decrease in the cardiac output, heart rate would increase because of increased activity of the sympathetic nervous system in a effort to maintain cardiac output.
Through which valve must blood pass as it moves from the right atrium to the right ventricle?
  • Ventricular ejection
  • Tricuspid
  • Capillaries
  • Potassium
Calculate the cardiac output if heart rate (HR) is 90 beats per minute, stroke volume (SV) is 110 ml/beat, end diastolic volume (EDV) is 140 ml, and end systolic volume (ESV) is 30 ml.View Available Hint(s)
  • Sodium- calcium exchanger on the sarcolemma
  • Tricuspid
  • Capillaries
  • 9.9 L/min
Why does blood flow through the cardiovascular system?
  • The atrioventricular valves and semilunar valves are both closed.
  • Because the heart establishes a pressure gradient
  • A vessel that carries blood away from the heart
  • The sum of the electrical activity of all cells of the body.
Which of these is the best definition of an artery?
  • A vessel that carries blood away from the heart
  • End diastolic volume and sympathetic nervous system stimulation.
  • The atrioventricular valves and semilunar valves are both closed.
  • The sum of the electrical activity of all cells of the body.
When the cardiac muscle cell is at rest, the concentration of ________is greater on the outside of the cells
  • Sodium and calcium
  • Sodium- calcium exchanger on the sarcolemma
  • Friction causes a loss of energy
  • Action potential
In skeletal muscle cells, action potentials cause the release of calcium from the SR by directly opening SR voltage-gated calcium channels. What causes the release of calcium from the SR in cardiac muscle cells?
  • Blood pressure decreases, because of the effects of friction between the vessels walls and the moving blood.
  • Influx of extracellular calcium ions opens ryanodine receptors allowing Ca2+ to flow out of the SR.
  • The sum of the electrical activity of all cells of the body.
  • The atrioventricular valves and semilunar valves are both closed.
What is the role of heart valves?
  • Heart valves ensure one- way flow of blood through the heart chambers
  • A vessel that carries blood away from the heart
  • The atrioventricular valves and semilunar valves are both closed.
  • The sum of the electrical activity of all cells of the body.
The P wave of the electrocardiogram begins right before __________.
  • Tricuspid
  • Capillaries
  • Potassium
  • Atrial systole
The movement of _____ into the cardiac muscle cell depolarizes the cardiac muscle cell.
  • Cells of the SA Nodes are the usual pacemaker, because they are autorhythmic cells and set the pace of the heartrate
  • Sodium and calcium
  • An increase in sympathetic nervous system activity would increase contractility (increasing available calcium), thus increasing stroke volume.Contractility causes an increase in stroke volume by decreasing end systolic volume; it does not change end diastolic volume.
  • Friction causes a loss of energy
Why does the pressure in the arteries and arterioles fall as the blood moves away from the heart?
  • Because the heart establishes a pressure gradient
  • The sum of the electrical activity of all cells of the body.
  • Friction causes a loss of energy
  • heat, immune cells, and cellular wastes
As part of a blood drive on campus for the American Red Cross, you and your friends have just donated 500 ml of blood. You are now relaxing at the student lounge, waiting for A&P lab to begin. Unfortunately, even though you are thirsty, you haven't bothered to buy yourself a drink. Other than a little soreness of the skin and tissue around your median cubital vein, you feel fine. How has your 500 ml decrease in blood volume most likely affected your cardiac output, heart rate, and stroke volume?
  • So blood is forced upward, toward the semilunar valves +++++Beginning contraction at the apex causes blood to be forced upward, through the semilunar valves, and into the aorta and pulmonary trunk. This makes ventricular ejection more efficient, much like squeezing a tube of toothpaste up from the bottom is more efficient at dispensing the toothpaste than is squeezing from the top.
  • closing of the semilunar valvesclosing of the atrioventricular valves++++Heart sounds are an extremely helpful diagnostic tool that is not invasive. The first heart sound, often described as a lubb, corresponds to the closing of the atrioventricular valves. The second heart sound is a sharper and crisper dupp that corresponds to the closing of the semilunar valves. Consequently, the two heart sounds mark the beginning and the end of ventricular systole.
  • Closing of the atrioventricular valvesThe QRS complex is a recording of ventricular depolarization. This depolarization begins just prior to the ventricular contraction it initiates. As the ventricles contract, the increase in ventricular pressure closes the atrioventricular valves, beginning isovolumetric contraction. As ventricular pressure increases above the corresponding blood vessel, only then do the semilunar valves open, initiating ventricular ejection..
  • Donating blood does not alter resting cardiac output. However, the decreased blood volume does decrease venous return and end diastolic volume. This decreases preload, thereby lowering stroke volume. By itself, decreased stroke volume would decrease cardiac output. But remember, the body still requires a resting blood flow of around 5 L/min. To meet this demand, homeostatic mechanisms quickly restore cardiac output to resting levels. For example, heart rate is increased as parasympathetic influence is removed and sympathetic activity is increased. Even though your blood volume is a bit low, your body has no problem compensating to meet your resting metabolic needs. Running away from a tiger? Now that might be a different story.
An extracellular recording of electrical activity of both autorhythmic and contractile cells of the heart is known as a(n)
  • Einthoven's triangle
  • Electrocardiogram
  • Ventricular ejection
  • Sodium and calcium
Which of these would cause an increase in blood flow through a vessel?
  • Vasodilation
  • A vessel that carries blood away from the heart
  • Capillaries
  • Atrial systole
An intracellular recording of electrical activity in either a contractile cell or autorhythmic cell is known as a(n) .
  • Atrial systole
  • Sodium and calcium
  • Action potential
  • Einthoven's triangle
What are the valve positions during isovolumetric contraction?
  • A vessel that carries blood away from the heart
  • The sum of the electrical activity of all cells of the body.
  • End diastolic volume and sympathetic nervous system stimulation.
  • The atrioventricular valves and semilunar valves are both closed.
Which cells act as the heart's pacemaker? Why are they the pacemaker cells
  • A vessel that carries blood away from the heart
  • Cells of the SA Nodes are the usual pacemaker, because they are autorhythmic cells and set the pace of the heartrate
  • The sum of the electrical activity of all cells of the body.
  • closing of the semilunar valvesclosing of the atrioventricular valves++++Heart sounds are an extremely helpful diagnostic tool that is not invasive. The first heart sound, often described as a lubb, corresponds to the closing of the atrioventricular valves. The second heart sound is a sharper and crisper dupp that corresponds to the closing of the semilunar valves. Consequently, the two heart sounds mark the beginning and the end of ventricular systole.
How would an increase in the sympathetic nervous system increase stroke volume?
  • An increase in sympathetic nervous system activity would increase contractility (increasing available calcium), thus increasing stroke volume.Contractility causes an increase in stroke volume by decreasing end systolic volume; it does not change end diastolic volume.
  • a decreased blood volume would decrease the end diastolic volume, thus lowering the stroke volume. Although this would initially lead to a decrease in the cardiac output, heart rate would increase because of increased activity of the sympathetic nervous system in a effort to maintain cardiac output.
  • closing of the semilunar valvesclosing of the atrioventricular valves++++Heart sounds are an extremely helpful diagnostic tool that is not invasive. The first heart sound, often described as a lubb, corresponds to the closing of the atrioventricular valves. The second heart sound is a sharper and crisper dupp that corresponds to the closing of the semilunar valves. Consequently, the two heart sounds mark the beginning and the end of ventricular systole.
  • Blood pressure decreases, because of the effects of friction between the vessels walls and the moving blood.
Consider three blood vessel segments of equivalent length and diameter: vessels A, B, and C. Pressure at the beginning of each segment is as follows: A) P = 100 mmHg; B) P = 80 mmHg; C) P = 60 mmHg. Pressure at the end of each segment is as follows: A) P = 70 mmHg; B) P = 50 mmHg; C) P = 30 mmHg. Which vessel has the greatest blood flow through the described segment?
  • Influx of extracellular calcium ions opens ryanodine receptors allowing Ca2+ to flow out of the SR.
  • All three vessels have the same resistance and the pressure gradient is the same in all three segments: A) ΔP = 100 - 70 = 30 mmHg; B) ΔP = 80 - 50 = 30 mmHg; C) ΔP = 60 - 30 = 30 mmHg.
  • The longer duration prevents tetanic contraction, which ensures that the heart chambers will relax and refill with blood before the next contraction
  • Contractibility ***increased sympathetic activity increases heart contractility. This causes cardiac fibers to contract more forcefully at all levels of preload. Regardless of end diastolic volume, this mechanism increases stroke volume by reducing end systolic volume.
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Multiple Choice Questions
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