Chapter 18: The Heart and Cardiovascular System Function

Cardiac muscle cells are __________. A) almost totally dependent on anaerobic metabolism B) mechanically, chemically, and electrically connected to one another C) multinucleated, with a low demand for nutrients D) nonstriated in appearance

B

Describe the pressures in the atria and ventricles that would cause the opening of the AV valves. A) Pressures in the atria and ventricles would be equal. B) Pressure in the atria would be greater than the pressure in the ventricles. C) Pressure in the ventricles would be greater than in the atria.

B

Which statement is correct regarding the intrinsic heart rate? A) During normal conditions, the pacemaker potential is the gradual repolarization that occurs. B) During parasympathetic stimulation, acetylcholine released by parasympathetic neurons opens chemically gated potassium channels in the plasma membrane. C) During sympathetic stimulation, acetylcholine released by sympathetic neurons binds to beta-1 receptors. D)During normal conditions, cells of the SA and AV nodes maintain a stable resting potential.

B

Which event does NOT happen during ventricular diastole? A) The second sound of the heart is heard. B) Atrioventricular valves close because of the contracting ventricles. C) Blood flows from the atria into the ventricles. D) Blood is pushed into the ventricles by the contracting atria.

B) Atrioventricular valves close because of the contracting ventricles.

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.

B) Most blood flows passively into the ventricles through open AV valves.

In an ECG recording, which of the following coincides with ventricular repolarization? A) P wave B) QRS complex C) P-R interval D) T wave

D

The portion of the tracing of an electrocardiogram, ECG, that represents ventricular depolarization is the __________. A) P-R segment B) Q wave C) P wave D) QRS complex E) T wave

D

Which structure provides a rapid-conduction path that tenses the papillary muscles before the ventricular myocardium contracts, preventing "slamming" of the right AV cusps? A) pectinate muscles B) trabeculae carneae C) chordae tendineae D) moderator band

D

Which of the following statements most accurately defines what is happening during the second phase of ventricular systole of the cardiac cycle? A) Pressure in the ventricles is rising but not enough to open the semilunar valves. B) Due to the pressure generated by the contracting ventricles, the second sound of the heart can be heard. C) All four valves of the heart are closed. D) Blood is being ejected from the ventricles through open semilunar valves.

D) Blood is being ejected from the ventricles through open semilunar valves.

Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________. A) ventricular diastole B) ventricular systole

A

Which of the following statements is correct concerning the cardiac cycle? A) In late ventricular diastole, all chambers are relaxed and filling to about seventy percent of their capacity. B) The event of the cardiac cycle that completes ventricular filling is ventricular systole. C) At the beginning of the cardiac cycle, the atria are relaxed and the ventricles are contracting. D) The backflow of blood towards the ventricles causes the semilunar valves to open. E) The first event of ventricular systole is ventricular ejection.

A

Increased pressure in the ventricles would close what valve(s)? A) AV valves only B) semilunar valves only C) both semilunar and AV valves

A) AV valves only

Put the phases of the cardiac cycle in the correct order, starting after ventricular filling. A) isovolumetric contraction, ventricular ejection, isovolumetric relaxation B) isovolumetric relaxation, ventricular ejection, isovolumetric contraction C) ventricular ejection, ventricular relaxation, isovolumetric contraction D) ventricular ejection, isovolumetric contraction, isovolumetric relaxation

A) isovolumetric contraction, ventricular ejection, isovolumetric relaxation

In the non-exercising heart, which event of the cardiac cycle lasts the longest? A) ventricular diastole B) atrial systole C) atrial diastole D) ventricular systole

C) atrial diastole

What causes the aortic semilunar valve to close? A) higher ventricular pressure than aortic pressure B) equal ventricular and aortic pressures C) greater pressure in the aorta than in the left ventricle

C) greater pressure in the aorta than in the left ventricle