What separates the parietal and visceral pericardium?
answer
pericardial cavity
question
Which of the following is the innermost layer of the heart?
answer
endocardium
question
Which layer of the heart wall contracts and is composed primarily of cardiac muscle tissue?
answer
myocardium
question
Which of these vessels returns blood to the left atrium of the heart?
superior vena cava
pulmonary trunk
pulmonary veins
coronary sinus
answer
pulmonary veins
question
Which of these muscles is particularly associated with anchoring the right and left atrioventricular valves?
papillary muscles
pectinate muscles
trabeculae carneae
myocardium
answer
papillary muscles --Papillary muscles contract to tense the right and left atrioventricular valves via the chordae tendineae just before ventricular systole
question
The right atrioventricular valve prevents backflow of blood from the right ventricle into the __________.
answer
right atrium --Flow from the right ventricle to the right atrium is prevented by the right atrioventricular valve.
question
Which statement is correct regarding the ventricles?
-The left ventricle empties into the pulmonary circuit.
-The right ventricle forms a complete circle in cross section.
-The left ventricle has a thinner wall than the right ventricle.
-The right ventricle empties into the pulmonary trunk.
answer
The right ventricle empties into the pulmonary trunk.
question
Cardiac tamponade results in ineffective pumping of blood by the heart because the excessive amount of fluid in the pericardial cavity will______.
answer
prevent the heart from filling properly with blood
question
Which heart chamber receives oxygenated blood from the lungs?
answer
left atrium
question
The role of the chordae tendineae is to open the AV valves at the appropriate time.
answer
False--The role of the chordae tendineae is to anchor the AV valves against the large pressure changes that occur as the ventricles contract.
question
The __________ valve is located between the right atrium and the right ventricle.
answer
tricuspid
question
Which valve is located between the right atrium and ventricle?
answer
tricuspid valve
question
Into which chamber of the heart do the superior vena cava, inferior vena cava, and coronary sinus return deoxygenated blood?
answer
right atrium
question
Which chamber of the heart sends oxygenated blood to the systemic circuit via the aorta?
answer
left ventricle
question
The right side of the heart is considered the systemic circuit pump
answer
False -- The right side of the heart pumps oxygen-poor blood to the lungs to be re-oxygenated. For this reason, the right side of the heart is considered the pulmonary circuit pump.
question
Why are gap junctions a vital part of the intercellular connection of cardiac muscles?
answer
Gap junctions allow action potentials to spread to connected cells.
question
What structures connect the individual heart muscle cells?
answer
intercalated discs
question
At what rate does the sinoatrial (SA) node depolarize?
answer
75 times per minute
question
Specifically, what part of the intrinsic conduction system generates the original stimulus that reaches the atrioventricular (AV) node, allowing it to conduct impulses to the atrioventricular bundle?
answer
sinoatrial (SA) node
question
Which portion of the electrocardiogram represents the depolarization wave received by the atria from the sinoatrial (SA) node?
answer
P wave
question
The order of impulse conduction in the heart, from beginning to end, is __________.
answer
SA node, AV node, bundle of His, bundle branches, and Purkinje fibers---The impulses of the heart originate at the SA node (pacemaker). The impulse is then transmitted to the AV node (atrioventricular node), where the impulse slows down to allow the atria to completely contract and thereby fill the adjacent ventricles. The AV node then transmits the impulse to the bundle of His, which branches into left and right bundle branches. The bundle branches give rise to the Purkinje fibers, which transmit the impulse to the ventricle walls and stimulate ventricular contraction
question
The P wave on an electrocardiogram represents __________.
answer
atrial depolarization
question
What does the QRS wave of the electrocardiogram (ECG) represent?
answer
ventricular depolarization
question
What is the period during the cardiac cycle when the ventricles are completely closed and blood volume in them remains constant as the ventricles contract?
isovolumetric relaxation phase
ventricular filling
ventricular ejection
isovolumetric contraction phase
answer
isovolumetric contraction phase --The prefix -iso means "equal," so during any isovolumetric stage the volume does not change.
question
At what point in the cardiac cycle is pressure in the ventricles the highest (around 120 mm Hg in the left ventricle)?
mid-to-late diastole (ventricular filling)
ventricular systole
early diastole (isovolumetric relaxation)
mid-to-late diastole (atrial contraction)
answer
ventricular systole--Left ventricular systole typically produces maximum pressures of around 120 mm Hg during systole.
question
During which of these stages are the pulmonary and aortic valves open?
phase 1
phase 2a
phase 2b
phase 3
answer
phase 2b --During phase 2b the pressure in the ventricles exceeds that of the aorta and pulmonary trunk, so their valves open and allow blood to be ejected.
question
The first heart sound (the "lub" of the "lub-dup") is caused by __________.
atrial contraction
closure of the semilunar valves
closure of the atrioventricular valves
ventricular contraction
answer
closure of the atrioventricular valves
question
Which of the following terms is correctly matched to its description?
-quiescent period: total heart relaxation between heartbeats
-diastole: contraction period
-stroke volume: amount of blood pumped out by each ventricle in one minute
-systole: relaxed period
answer
quiescent period: total heart relaxation between heartbeats
question
As your muscles contract during activity, more blood is returned to the heart. Which variable would be affected and what would be the outcome of this action?
Afterload would increase, which would increase cardiac output.
Contractility would be increased, which would increase cardiac output.
End-systolic volume would be increased, which would increase cardiac output.
Preload would be increased, which would increase cardiac output.
answer
Preload would be increased, which would increase cardiac output.
question
What causes heart sounds?
opening of heart valves
blood flowing from the atria into the ventricles
pressure of blood in the ventricles
heart valve closure
answer
heart valve closure
question
Which of the following would cause a DECREASE in cardiac output (CO)?
heightened use of skeletal muscle
decreasing thyroid function (thyroxine)
suddenly standing up from a supine position
an increase in adrenal medulla output (epinephrine)
answer
decreasing thyroid function (thyroxine)
question
Calculate the stroke volume if the end diastolic volume (EDV) is 135 mL and the end systolic volume (ESV) is 60 mL.
answer
75 mL
question
Which of the following increases stroke volume?
severe blood loss
decrease in preload
decrease in end diastolic volume (EDV)
exercise
answer
exercise
question
Which of the following would increase cardiac output?
parasympathetic stimulation
epinephrine
decreased calcium during contraction
high blood pressure
answer
epinephrine
question
Increasing end-diastolic and end-systolic volume will increase stroke volume.
answer
False--Increasing end-diastolic volume will increase stroke volume. However, increasing end-systolic volume will decrease stroke volume.
question
Which of the following is NOT a factor that increases stroke volume?
increasing afterload
increasing sympathetic stimulation
increasing contractility
increasing preload
answer
increasing afterload
question
What best describes after load?
back pressure exerted by arterial blood
degree of stretch of the heart muscle
cardiac reserve
contractility of cardiac muscle
answer
back pressure exerted by arterial blood
question
The atrioventricular (AV) valves are closed ________.
by the movement of blood from atria to ventricles
when the ventricles are in diastole
while the atria are contracting
when the ventricles are in systole
answer
when the ventricles are in systole
question
During the period of ventricular filling ________.
-blood flows mostly passively through the atria and the open atrioventricular (AV) valves into the ventricles
-the aortic and pulmonary semilunar valves are open
-the atria remain in diastole
-pressure in the heart is at its peak
answer
blood flows mostly passively through the atria and the open atrioventricular (AV) valves into the ventricles
question
Given an end diastolic volume (EDV) of 120 ml / beat and an end systolic volume (ESV) of 50 ml / beat, the stroke volume (SV) would be ________.
answer
70 ml/beat
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