Chapter 20

If aa typical adult male has a heart rate of 70 beats per minutes, how much blood would flow through the heart each minute? 700 mL 70 mL 5,250 mL 4,900 mL

4,900 mL

If the stroke volume (mL of blood leaving the left ventricle during each contraction) is 70mL and the SA node is functioning properly, how much blood is being ejected from the left ventricle each minute?

4.9 L/min

The stroke volume at rest is what percentage of end-diastolic volume? 100% 80-90% 50-60% 40-50% 0%

50-60%

Stroke volume is increased by Increased preload. Decreased afterload. Increased contractility. All of these.

All of these

Which of the following techniques might be useful for a failing heart? cardiac transplant intra-aortic balloon pump ventricular assist device cardiomyoplasty All of these choices might be useful.

All of these choices might be useful.

Damage or dysfunction of the sinoatrial node does not result in cardiac failure because additional portions of the autorhythmic fibers can create action potentials. If a heart rate was measured at 30 beats/min, it may indicate that these fibers are creating spontaneous action potential in the heart. Both Bundle of His and Purkinje fibers Atrioventricular node Bundle of His Purkinje fibers

Both Bundle of His and Purkinje fibers

Which of the following is NOT a positive inotropic agent? Norepinephrine Digoxin Thyroxine Calcium channel blockers

Calcium channel blockers

Which of the following is NOT a negative inotropic agent? Calcium channel blockers Anesthetics Epinephrine None of these

Epinephrine

T/F Extreme exercise can increase the cardiac output up to 100-fold.

False

T/F The Frank-Starling law of the heart suggests that the greater the afterload, the greater the sarcomere stretch, the greater the stroke volume.

False

Which structures permit action potentials in the autorhythmic cardiac fibers to move from one cell immediately to an adjacent cell?

Gap Junction

The first functional organ to develop in the embryo is the: lungs liver heart urinary bladder small intestine

Heart

Hypertension increases aortic pressure. decreases aortic pressure. decreases ventricular pressure. none of these.

Increases aortic pressure

Channels in cardiac muscle fiber membranes in the sinoatrial node that open when a threshold of -40 mV is reached are... Potassium channels. L-type calcium channels. F-type sodium channels. T-type calcium channels.

L-type calcium channels.

T/F A normal resting stroke volume is around 70-mL.

True

T/F Cardiac output can be determined by multiplying the heart rate by the stroke volume.

True

T/F Contraction of the cardiac muscle sarcomeres during ventricular systole provides the force needed to eject blood from the heart.

True

T/F More blood flows through the coronary arteries during ventricular diastole than ventricular systole.

True

T/F Resting cardiac output (CO) in a well-conditioned athlete is about the same as in a healthy untrained person.

True

T/F Semilunar valves close during ventricular diastole to prevent blood from flowing from the arteries into the ventricles.

True

T/F The typical cardiac output for a healthy adult is around 5-liters per minute.

True

T/F When all heart valves are closed during isovolumetric ventricular contraction, the amount of blood (volume) is constant but blood pressure increases.

True

All of the following defects are seen in Tetralogy of Fallot EXCEPT a patent ductus arteriosus. an interventricular septal defect. an aorta that emerges from both ventricles. a stenosed pulmonary valve. an enlarged right ventricle.

a patent ductus arteriosus.

What is occurring during isovolumetric contraction? the amount of blood in each atria is the same the semilunar valves are open and the AV valves are closed the point at which all blood has been ejected from the ventricles all four valves are closed both atria are ejecting blood at the same time

all four valves are closed

Ventricular muscle is relaxed during ventricular diastole approximately half of the cardiac cycle during atrial systole all of the above

all of the above

An electrocardiogram can help determine all of the following except: a cause of chest pain if a heart attack has occurred if the heart has enlarged if the conduction pathway is functioning normally all of these choices can be determined during an ECG

all of these choices can be determined during an ECG

The P-wave in an electrocardiogram occurs during ventricular repolarization. artial repolarization. atrial depolarization. ventricular depolarization.

atrial depolarization

Which of the following are NOT part of the conducting system in the heart?

atrioventricular (AV) valve

Cardiac muscle cells (fibers) that do not contract but instead create and conduct the action potential throughout the heart are... autorhythmic fibers. contractile fibers. atrial fibers. ventricular fibers.

autorhythmic fibers.

The amount of blood ejected from either ventricle every minute is called: stroke volume end-diastolic volume afterload cardiac output heart rate

cardiac output

The first sound heard in a stethoscope during the cardiac cycle is the contraction of the ventricles contraction of the atria closing of the AV valves closing of the semilunar valves

closing of the AV valves

Which sequence of events is accurate in describing what occurs when an action potential arrives along the membrane of a contractile cardiac muscle fiber?

fast sodium channels open, fast potassium channels open, fast calcium channels open, slow potassium channels open sodium diffuses into the fiber, potassium diffuses out of the fiber, calcium diffuses into the fiber, potassium diffuses out of the fiber the membrane depolarizes, repolarizes to 0 mV, stabilizes for a period of time at 0 mV, and then completely repolarizes to -90 mV

Atrial systole is necessary to close the AV valves fill the ventricles with blood allow blood to passively fill the chambers fill the aortas with blood

fill the ventricles with blood

The visceral layer of the serous pericardium: is fused to the fibrous pericardium is the fluid that offers protection to the heart is the outer layer of the heart is a tough, inelastic layer that anchors the heart in the mediastinum is also called the pericardial cavity

is the outer layer of the heart

Which of the following is not a component of the internal heart? papillary muscle chordae tendineae interventricular septum pectinate muscle left auricle

left auricle

The term used to describe a backflow of blood from the left ventricle into the left atrium is: aortic stenosis mitral valve prolapse semilunar valve prolapse mitral valve stenosis aortic insufficiency

mitral valve prolapse

The right side of the heart is concerned with two of the choices are correct pumping oxygenated blood pulmonary circulation systemic circulation

pulmonary circulation

Comparatively, which phase is the longest during an action potential in a ventricular contractile fiber? refractory depolarization contraction repolarization

refractory

Which of the following is the correct pathway of blood starting at the right atrium? right atrium, left atrium, left ventricle, right ventricle, pulmonary trunk, pulmonary veins, aorta right atrium, aorta, left ventricle, left atrium, pulmonary trunk, right ventricle, pulmonary veins right atrium, right ventricle, pulmonary trunk, pulmonary veins, left atrium, left ventricle, aorta right atrium, pulmonary trunk, left atrium, left ventricle, pulmonary veins, aorta, right ventricle

right atrium right ventricle pulmonary trunk pulmonary veins left atrium left ventricle aorta

Towards the end of ventricular systole when ventricular blood pressure exceeds aortic blood pressure semilunar valves open AV valves open semilunar valves close AV valves close

semilunar valves open

Atrial repolarization occurs during ventricular depolarization and, consequently, would be viewed on an electrocardiogram (if it was visible) during the QRS complex. the P-wave. the T-wave. both the P-wave and the T-wave.

the QRS complex.

F-type sodium channels in cardiac fiber membranes located in the sinoatrial node... open when the membrane potential decreases. allow sodium to diffuse out of the muscle fibers. close when the membrane potential gets less negative. two of the choices are correct.

two of the choices are correct.

Semilunar valves function to prevent blood from flowing back into the atria during atrial systole ventricles during ventricular systole ventricles during ventricular diastole atria during atrial diastole

ventricles during ventricular diastole

Blood leaves the heart during ventricular ejection ventricular relaxation isovolumetric ventricular relaxation passive ventricular filling

ventricular ejection