Chapter 20 Review

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Cardiac muscle tissue __________.

has its own intrinsic conduction system to set the pace of the beating heart

Cardiac reflexes that adjust cardiac function are triggered by sensory input to the cardiac centers. Which sensory information is NOT something that triggers these reflexes?

heart rate

What is the term for the volume of blood that is left in the ventricle after the QRS wave?

End-systolic volume

What factors would make stroke volume greater?

Increased end-diastolic volume and decreased end-systolic volume

Which factor does NOT increase stroke volume?

Increased heart rate

Which of the following could increase the strength of the contraction of a ventricle?

Increased stretch on the ventricle

How does sympathetic stimulation increase the heart rate?

Increasing Na+ and Ca2+ inflow into SA node cells

What ion movement is responsible for the rapid depolarization phase of the ventricular muscle cell action potential?

Na+ inflow

On an ECG, which electrical feature accompanies depolarization of the atria?

P wave

What is the correct sequential path of a normal action potential in the heart?

SA node, AV node, bundle AV, bundle branches, Purkinje fibers

Which of the following is NOT a component of the Frank-Starling Principle?

Slowing the heart rate decreases stroke volume.

On an ECG, which electrical feature accompanies repolarization of the ventricles?

T wave

What is the definition of cardiac output?

The amount of blood pumped out of the left ventricle in one minute

What is the meaning of the term preload?

The degree of stretching in the ventricular muscle during ventricular diastole

What is ejection fraction?

The percentage of the end-diastolic volume represented by the stroke volume

Which of the following statements concerning contractile cells and the heartbeat is INCORRECT?

The plateau phase of the contractile cell's action potential is the result of calcium ions moving out of the cell.

The dicrotic notch marks the point when the __________.

aortic valve closes

What feature allows the blood supply to the heart muscle to remain relatively constant regardless of the pressure changes in the coronary arteries due to heartbeats?

arterial anastomoses

The right and left coronary arteries originate at the base of the __________.

ascending aorta

Atrial systole _________________ .

begins at the peak of the P wave

Activation of which kind of receptor causes heart rate to increase?

beta-one

The long plateau phase of the cardiac muscle action potential is due to

calcium channels remaining open

What is meant by the term afterload?

how much tension or force the ventricle has to generate to push the blood out of the ventricle

Blood flows from the left atrium through the __________ to the left ventricle.

mitral valve

Rupture of the papillary muscles in the left ventricle may result in

mitral valve prolapse.

What is happening during isovolumetric contraction?

no blood is being ejected from the ventricles

To listen to the aortic valve, one would hold the stethoscope ________________________ .

on the right side of the sternum in the second intercostal space

Contractions of the papillary muscles

prevent the atrioventricular valves from reversing into the atria.

When deoxygenated blood leaves the right ventricle through a semilunar valve, it is forced into the __________.

pulmonary arteries

Blood leaves the right ventricle by passing through the

pulmonary valve

What structures in the conduction system conduct impulses very rapidly to the ventricular myocardium?

purkinje fibers

When the heart rate climbs to over 200 beats per minute, the time in diastole is dramatically reduced. This reduced time of relaxation would _________________.

reduce filling time

Coronary veins empty into the

right atrium

Which chamber of the heart receives blood from the superior and the inferior venae cavae?

right atrium

Which of the following contains the trabeculae carneae?

right ventricle

The amount of blood pumped out of each ventricle during a single beat is the __________.

stroke volume

The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the

systolic ejection phase.

Which of the following occurs during the first phase of ventricular systole?

the AV valves close, and ventricular pressure rises.

Which of the following events does NOT occur because of the QRS wave?

the AV valves open

The first sound of the heart occurs as a result of __________.

the QRS complex

The left coronary artery supplies blood to __________.

the anterior interventricular artery and the circumflex branch

At the end of the T wave, _______________ .

the aortic valve closes

At the end of the QRS complex, ______________ .

the aortic valve opens

The conduction delay that occurs at the AV node allows __________.

the atria to contract before the ventricles begin to contract

Blood is supplied to the myocardium by

the coronary arteries.

An action potential in cardiac contractile cells is the same as an action potential in skeletal muscle cells EXCEPT for ______.

the presence of a plateau phase in cardiac contractile cells

Tetanic muscle contractions don't occur in a normal cardiac muscle because

the refractory period lasts until the muscle relaxes

Muscular ridges on the inner surface of the ventricles are called

trabeculae carneae.

The QRS complex of the ECG appears as the __________.

ventricles depolarize

Once pressure in the ventricles exceeds that of the aorta and pulmonary trunk, the semilunar valves are pushed open. This point marks the beginning of ______________ .

ventricular ejection

If the average heart rate is 75 beats per minute, each cardiac cycle lasts _______________ msec.

800

Why are the SA node cells autorhythmic?

They have a slow inflow of Na+ after repolarization

What is the function of the chordae tendineae?

To anchor the AV valve flaps and prevent backflow of blood into the atria

Cardiac cells damaged by infarction will show all of the following except

an increase in metabolic activity.

The coronary arteries emerge at the base of the __________.

aorta

The amount of blood pumped by the left ventricle in one minute during the cardiac cycle is called the __________.

cardiac output

The increased production of pericardial fluid leading to restriction of the movement of the heart is called ____________ .

cardiac tamponade

The first heart sound, S1, also known as lubb, corresponds to the ___________.

closing of the atrioventricular valves

The second heart sound, S2, also known as dubb, corresponds to the ________________ .

closing of the semilunar valves

As blood leaves the right ventricle, it passes through the ________ and then into the pulmonary trunk.

conus arteriosus

Cardiac muscle cells are nourished via blood supply provided from the __________.

coronary circuit

On an ECG, a P-R interval longer than 200 msec would indicate ________________ .

damage to the AV node or internodal pathways

If the force of ventricular contraction increases, what will happen to the end-systolic volume?

decrease

The cardiac skeleton is best described as __________________ .

dense bands of tough elastic tissue that encircle the heart valves

The ________ is the volume of blood in a ventricle at the beginning of systole

end-diastole volume

At the end of atrial systole, each ventricle contains the maximum amount of blood that it will hold. This volume of blood is called the _______________.

end-diastolic volume (EDV)

The ________ is the amount of blood in a ventricle after it has contracted and before it begins to refill.

end-systolic volume

The amount of blood remaining in the ventricle when the semilunar valve closes is the

end-systolic volume

During exercise, an important control mechanism to increase cardiac output is __________.

increased sympathetic activity to the ventricles

During ventricular systole, the blood volume in the atria is __________, and the volume in the ventricle is __________

increasing; decreasing

Valvular malfunction in the heart __________.

interferes with movement of blood through the heart

Which heart chamber has the thickest muscular walls?

left ventricle

Pulmonary arteries carry blood to the __________.

lungs


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