Biology - chapter 20

The following are structural components of the conducting system of the heart. 1. Purkinje fibers, 2. AV bundle, 3. AV node, 4. SA node, 5. bundle branches. The sequence in which excitation would move through this system is a. 1, 4, 3, 2, 5. b. 3, 2, 4, 5, 1. c. 3, 5, 4, 2, 1. d. 4, 3, 2, 5, 1. e. 4, 2, 3, 5, 1.

4, 3, 2, 5, 1.

The following is a list of vessels and structures that are associated with the heart. What is the correct order for the flow of blood entering from the systemic circulation? 1. right atrium, 2. left atrium, 3. right ventricle, 4. left ventricle, 5. venae cavae, 6. Aorta, 7. pulmonary trunk, 8. pulmonary veins a. 1, 2, 7, 8, 3, 4, 6, 5 b. 1, 7, 3, 8, 2, 4, 6, 5 c. 5, 1, 3, 7, 8, 2, 4, 6 d. 5, 3, 1, 7, 8, 4, 2, 6 e. 5, 1, 3, 8, 7, 2, 4, 6

5, 1, 3, 7, 8, 2, 4, 6

Considering the left ventricle, why does isovolumetric ventricular contraction occur during ventricular systole? a. The ventricle needs to pressurize the blood to close the aortic valve. b. Ventricular pressure is greater than atrial pressure so the ventricle cannot eject blood. c. The bicuspid valve needs time to shut before the ventricle can eject blood. d. Aortic pressure is higher than ventricular pressure and the ventricle must pressurize the blood to open the aortic valve. e. The ventricle is still filling with blood and therefore cannot eject blood during this time.

Aortic pressure is higher than ventricular pressure and the ventricle must pressurize the blood to open the aortic valve.

The term ________ refers to blockage in the coronary circulation. a. congestive heart failure b. atherosclerosis c. coronary artery disease d. embolism e. phlebitis

coronary artery disease

Cardiac output can be increased by all of the following except a. decreasing ejection fraction. b. decreasing end systolic volume. c. increasing stroke volume. d. increasing ejection fraction. e. decreasing ejection fraction.

decreasing ejection fraction.

The ________ is the volume of blood in a ventricle at the beginning of systole. a. ejection fraction b. end-diastole volume c. start-diastolic volume d. end-systolic volume e. stroke volume

end-diastole volume

The atrioventricular valves permit blood flow a. in one direction only. b. in both directions. c. in many directions. d. in opposite directions on the right and left. e. from a ventricle to an atrium.

in one direction only.

The foramen ovale in the fetal heart is located in the a. right atrium. b. left atrium. c. right ventricle. d. left ventricle. e. interatrial septum.

interatrial septum.

Pericardial fluid a. provides oxygen to the heart muscle. b. is located between the myocardium and the endocardium. c. is a lubricant between the heart and the pericardial sac. d. consists of plasma that has leaked out of whole blood. e. flows through the four chambers of the heart.

is a lubricant between the heart and the pericardial sac.

The long plateau phase of the cardiac muscle action potential is due to a. movement of fewer sodium ions across the cell membrane. b. calcium channels remaining open. c. increased membrane permeability to potassium ion. d. decrease in the amount of calcium diffusing across the membrane. e. increased membrane permeability to sodium ions.

calcium channels remaining open.

Repolarization of the ventricles is represented on an electrocardiogram by the a. P wave. b. T wave. c. S wave. d. QRS complex. e. PR complex.

T wave.

The coronary sulcus is a groove that a. marks the border between the atria and ventricles. b. marks the boundary line between the right and left ventricles. c. marks the boundary line between the right and left atria. d. separates the atrioventricular valves from the atria. e. separates the coronary arteries from the coronary veins.

marks the border between the atria and ventricles.

Thick projections of muscle in the ventricles that anchor chordae tendineae are called a. pectinate muscles. b. conus arteriosus. c. papillary muscles. d. trabeculae carneae. e. auricles.

papillary muscles.

The ________ circuit carries blood to and from the lungs. a. pulmonary b. systemic c. oxygen d. portal e. primary

pulmonary

Compared to the right ventricle, the left ventricle has all the following characteristics except a. has a thicker wall. b. is round in cross section. c. pumps a greater volume. d. works harder. e. produces about four to six times more pressure when it contracts.

pumps a greater volume.

Stroke volume depends on all of the following factors except a. end diastolic volume. b. the contractility of the ventricle. c. the pressure required to pump blood into the aorta. d. venous return of blood to the heart. e. respiratory rate.

respiratory rate.

Blood is supplied to the myocardium by a. the coronary sinus. b. contact with blood in the pumping chambers. c. the coronary arteries. d. arteries that branch from the pulmonary arteries. e. arteries that branch off the subclavian arteries.

the coronary arteries.