Questions and All Correct Answers
2026 Updated.
Blood returning to the heart from the lungs
A.) enters the right atrium
B.) enter the right ventricle
C.) enter the left atrium
D.) enters the left ventricle
E.) travels in the pulmonary artery to the heart - Answer C.) enter the left atrium
If the SA node of the heart was damaged so that SA node cells no longer reached threshold
A.) the heart could no longer beat because the SA node is the only tissue that can serve as the
pacemaker of the heart
B.) another autorhythmic tissue in the heart could take over as pacemaker and the heart rate
would most likely increase
C.) another autorhythic tissue in the heart could take over as pacemaker and the heart rate
would most likely decrease - Answer C.) another autorhythic tissue in the heart could take
over as pacemaker and the heart rate would most likely decrease
The absolute refractory period of cardiac muscle
A.) is over before contraction begins (does not occur during contraction)
B.) is like skeletal muscle; it is very short (less than 2 msec) compared to the duration of
contraction (more than 100 msec)
C.) lasts about as long as contraction
D.) allows tetanic contractions of the heart to occur
E.) A, B and D - Answer C.) lasts about as long as contraction
If all the Ca++ channels on the cell membrane of cardiac muscle cells were blocked, contraction
_______ occur.
A.) could not
B.) could still - Answer A.) could not
The cardiac impulse is delayed 0.1 sec (1/10 of a second) at the ______ to give time for the atria
to contract before the ventricles begin contracting.
A.) SA node
B.) Purkinje fibers
,C.) AV bundle (bundle of His)
D.) AV node
E.) right and left bundle branches - Answer D.) AV node
In complete heart block, there is no correlation between
A.) QRS complexes and T waves
B.) P waves and QRS complexes - Answer B.) P waves and QRS complexes
A heart rate of 250 beats per minute could occur during
A.) bradycardia
B.) flutter
C.) bradycardia or flutter - Answer B.) flutter
Concerning the cardiac cycle, which is true?
A.) The first heart sound is due to the closing of the semilunar valves
B.) the chordae tendineae open and close the bicuspid and tricuspid (AV) or atrioventricular)
valves
C.) During ventricular systole, the volume of blood in the ventricle decreases
D.) the aortic semilunar valve closes when ventricular pressure is greater than aortic pressure
E.) before atrial contraction, the ventricles are empty (contain no blood) - Answer C.) During
ventricular systole, the volume of blood in the ventricle decreases
Which of the choices listed is closest to a normal aortic diastolic blood pressure?
A.) 150 mmHg
B.) 80 mmHg
C.) 0 mmHg
D.) 120 mmHg
E.) 50 mmHg - Answer B.) 80 mmHg
The right ventricle ________ the left ventricle.
A.) generates higher pressures than
B.) wall is thinner than the wall of
C.) normally pumps less blood than
D.) B and C - Answer B.) wall is thinner than the wall of
, Which below decreases heart rate?
A.) increased epinephrine
B.) increased sympathetic impulses to the heart
C.) increased parasympathetic impulses to the heart
D.) increased sympathetic and decreased parasympathetic impulses to the heart - Answer C.)
increased parasympathetic impulses to the heart
Cardiac output
A.) is the volume of blood pumped by both ventricles per minute
B.) is normally about 70ml
C.) is end diastolic volume minus end systolic volume (CO=EDV-ESV)
D.) is the volume of blood pumped by either ventricle per minute
E.) normally will decreased with increased activity - Answer D.) is the volume of blood
pumped by either ventricle per minute
Increased venous return ______ end diastolic volume
A.) increase
B.) decreases
C.) does not affect - Answer A.) increase
Which below is correctly matched?
A.) Starling's Law of the Heart-extrinsic control of stroke volume
B.) changes in contractility- intrinsic control of stroke volume
C.) sympathetic nervous system- extrinsic control of stroke volume - Answer C.) sympathetic
nervous system- extrinsic control of stroke volume
(T/F) The left side of the heart pumps blood to the lungs, the right side of the heart pumps
blood to the rest of the body. - Answer False
Blood in the left atrium enters the left ventricle through the ______ valve.
A.) semilunar
B.) tricuspid
C.) bicuspid (mitral) - Answer C.) bicuspid (mitral)
The long refractory period of cardiac muscle ______ tetanic contractions (tetanus) in the heart.
A.) causes