Chapter 20 Review
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
