Anatomy 2 Heart Electrical Activity/Cardiac Cycle
When ventricular pressure becomes greater than atrial pressure
At what point during the cardiac cycle does the AV valve close? a. When ventricular pressure becomes greater than aortic pressure b. When the semilunar valve opens c. When aortic pressure becomes greater than ventricular pressure d. When ventricular pressure becomes greater than atrial pressure
When atrial pressure becomes greater than ventricular pressure
At what point in the cardiac cycle does the AV valve open? a. When aortic pressure becomes greater than ventricular pressure b. When ventricular pressure becomes greater than aortic pressure c. When the semilunar valve closes d. When atrial pressure becomes greater than ventricular pressure
When pressure in the ventricle becomes less than aortic pressure
At what point in the cardiac cycle does the semilunar valve close? a. When ventricular pressure becomes greater than aortic pressure b. When pressure in the ventricle becomes less than aortic pressure c. When ventricular pressure becomes greater than atrial pressure d. When atrial pressure becomes greater than ventricular pressure
When ventricular pressure becomes greater than aortic pressure
At what point in the cardiac cycles does the semilunar valve open? a. When atrial pressure becomes greater than ventricular pressure b. When the AV valve closes c. When ventricular pressure becomes greater than atrial pressure d. When ventricular pressure becomes greater than aortic pressure
Atrial contraction
Atrial pressure is greater than ventricular pressure during which phase of the cardiac cycle? a. Ventricular ejection b. Isovolumetric contraction c. Atrial contraction d. Isovolumetric relaxation
Semilunar valves are open
During the ventricular ejection phase of the cardiac cycle, which of the following is true? a. Ventricles are in diastole b. Semilunar valves are open c. AV valves are open d. Atria are in systole
P wave
Contraction of the atria is triggered by electrical activity that is recorded on the ECG tracing as the ________. a. T wave b. QRS complex c. P wave d. A wave
Pressure in the atria would be greater than pressure in the ventricles
Describe the pressures in the atria and ventricles that would cause the opening of the AV valves. a. Pressure in the ventricles would be greater than in the atria b. Pressures in the atria and ventricles would be equal c. Pressure in the atria would be greater than pressure in the ventricles
Pacemaker cells are able to stimulate action potentials in the cardiac contractile cells
How does the presence of pacemaker cells affect the electrical activity of the cardiac contractile cells? a. Pacemaker cells are able to stimulate action potentials in the cardiac contractile cells b. Pacemaker cells increase the frequency of normally occurring action potentials in the cardiac contractile cells c. Activity of pacemaker cells cancels out action potentials of cardiac contractile cells
From a region of high pressure to a region of low pressure
In what direction does blood flow through the heart? a. From a region of high oxygen content to a region of low oxygen content b. From ventricles to atria c. From a region of high pressure to a region of low pressure d. From a region of high volume to a region of low volume
AV valves only
Increased pressure in the ventricles would close what valve(s)? a. AV valves only b. Both semilunar and AV valves c. Semilunar valves only
Ventricular diastole
Isovolumetric relaxation and ventricular filling take place during ________. a. Ventricular diastole b. Ventricular systole
The semilunar and AV valves are closed
Isovolumetric relaxation is characterized by which of the following? a. Blood flows backward through the heart from high to low pressure b. The semilunar and AV valves are closed c. Pressure in the atrium exceeds pressure in the ventricle d. Pressure in the ventricle exceeds pressure in the aorta
Ventricular ejection
Most of the decrease in ventricular volume takes place during which phase of the cardiac cycle? a. Isovolumetric relaxation b. Ventricular ejection c. Atrial contraction d. Ventricular filling
Atrial contraction
Most of the increase in left ventricular volume takes place during which phase of the cardiac cycle? a. Atrial contraction b. Ventricular filling c. Ventricular ejection d. Isovolumetric relaxation
Isovolumetric contraction, ventricular ejection, isovolumetric relaxation
Put the phases of the cardiac cycle in the correct order, starting after ventricular filling. a. Isovolumetric contraction, ventricular ejection, isovolumetric relaxation b. Ventricular ejection, ventricular relaxation, isovolumetric contraction c. Isovolumetric relaxation, ventricular ejection, isovolumetric contraction d. Ventricular ejection, isovolumetric contraction, isovolumetric relaxation
Pacemaker cells
The specialized cardiac cells of the SA node are most precisely known as ________. a. Intrinsic cells b. Atrial cells c. Pacemaker cells d. Contractile cells
Ventricular ejection
Ventricular pressure is greater than aortic pressure during which phase of the cardiac cycle? a. Ventricular ejection b. Isovolumetric relaxation c. Ventricular filling d. Isovolumetric contraction
Greater pressure in the aorta than in the left ventricle
What causes the aortic semilunar valve to close? a. Greater pressure in the aorta than in the left ventricle b. Higher ventricular pressure than aortic pressure c. Equal ventricular and aortic pressures
To prevent backward flow of blood
What is the main function of heart valves? a. To pump blood through the heart b. To prevent backward flow of blood c. To separate the left and right atria d. To separate the atria and ventricles
The ventricles are in diastole
When the atria contract, which of the following is true? a. The atria are in diastole b. The ventricles are in diastole c. The semilunar valves are open d. The AV valves are closed
Action potentials are delayed at the AV node
Which of the following characteristics of the intrinsic conduction system best explains why atrial contraction finishes before ventricular contraction begins? a. Pacemaker cells are autorhythmic b. Purkinje fibers have the slowest rate of spontaneous depolarization c. The SA node initiates electrical impulses d. Action potentials are delayed at the AV node
AV bundle
Which of the following functions as the electrical connection between the atria and ventricles? a. AV bundle b. SA node c. AV node d. Purkinje fibers
Most blood flows passively into the ventricles through open AV valves
Which of the following is correct about the filling of the ventricles? a. The majority of ventricular filling is caused by contraction of the atria b. Most blood flows passively into the ventricles through open AV valves
EDV
Which of the following is equivalent to the ventricular volume during isovolumetric contraction? a. ESV b. SV c. EDV d. MVV
ESV
Which of the following is equivalent to the ventricular volume during isovolumetric relaxation? a. EDV b. ESV c. SV d. MVV
AV valves are closed
Which of the following is true during ventricular systole? a. AV valves are closed b. Atria are in systole c. Ventricles are relaxed d. Ventricles are empty
SA node
Which part of the intrinsic conduction system initiates the depolarizing impulse and normally sets the pace for the entire heart? a. AV bundle b. SA node c. Purkinje fibers d. AV node