a&p 2 midterm ch 17
Calculate the end-systolic volume (ESV) if the end-diastolic volume (EDV) in a resting heart is 110 ml and stroke volume (SV) is 70 ml.
40 ml
Approximately how much blood is pumped from each ventricle during the ventricular ejection phase?
70 ml
What percentage of atria blood flows passively into the ventricles?
80%
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?
AV node
Increased pressure in the ventricles would close what valve(s)?
AV valves only
Which of the following chemical messengers decreases heart rate?
Acetylcholine
Which of the following terms refers to the force the ventricles must overcome to eject blood into their respective arteries?
Afterload
Where does the left ventricle send blood?
Aorta
If a drop of blood is located in the left ventricle, through what structure will it next pass?
Aortic semilunar valve
What blood vessels do ventricles always pump blood into?
Arteries
Which hormone decreases cardiac output by decreasing blood volume and preload?
Atrial natriuretic peptide
Which of the following hormones decrease cardiac output by decreasing blood volume and preload?
Atrial natriuretic peptide
What cardiac dysrhythmia does a patient have with a resting heart rate of 50 beats per minute?
Bradycardia
The plateau phase of the cardiac action potential is due to __________.
Ca2+ influx
Which of the following ion channels are time-gated closing channels?
Calcium ion channels
What structure attaches the cusps of the atrioventricular valves to the papillary muscles?
Chordae tendineae
Which coronary artery supplies the left atrium and parts of the left ventricle?
Circumflex artery
Which of the following events can be heard most easily with a stethoscope?
Closing of atrioventricular valves
Which of the following cell populations does not spontaneously generate action potentials in the cardiac conduction system?
Contractile cells
What provides a graphic representation of all the action potentials occurring in the heart?
Electrocardiogram
Name the three layers of the heart wall, and indicate the layer that is also called the visceral pericardium.
Epicardium (visceral pericardium), myocardium, and endocardium
What are the three layers of the heart wall from superficial to deep?
Epicardium, myocardium, and endocardium
Which opening in the interatrial septum of the fetal heart connects the right and left atrium?
Fossa ovalis
Which of the following factors may contribute to an increase in stroke volume?__________.
Increase preload and contractility, and decrease afterload
Which of the following factors would increase cardiac output to the greatest extent?
Increased heart rate and increased stroke volume
Which of the following statements best describes the apex of the heart?
Inferior tip of the heart and points toward the left side
Which blood vessel returns deoxygenated blood to the right atrium?
Inferior vena cava
Looking in a microscope, what are the visible structures that join cardiac muscle cells?
Intercalated discs
Which of the following structural components is only found in cardiac muscles?
Intercalated discs
Which structure separates the right and left ventricles?
Interventricular septum
Which of the following statements describes the total refractory period of cardiac muscle?
It is longer than the total refractory period for skeletal muscle.
How will the cardiac output change if you double the heart rate but reduce the stroke volume by one-half?
It will not change.
Which cardiac chamber has the thickest wall?
Left ventricle
Which chamber generates the highest pressure during systole?
Left ventricle
Which of the following valve would be affected if papillary muscles and/or chordae tendinae stopped functioning?
Mitral valve
Which of the following is correct about the filling of the ventricles?
Most blood flows passively into the ventricles through open AV valves.
Which layer of the heart wall is composed predominantly of cardiac muscle tissue?
Myocardium
Contraction of the atria results from which wave of depolarization on the ECG tracing?
P wave
Which of the following structures is associated with the atria?
Pectinate muscles
During what part of the action potential will calcium ions enter the contractile cell?
Plateau phase
Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.
Pressure in the atria would be greater than the pressure in the ventricles.
What is the function of the valves in the heart?
Prevent backflow of blood through the heart
Which of the following vessels delivers oxygen-poor blood to the lungs?
Pulmonary Arteries
Which of the following vessels carries oxygenated blood?
Pulmonary vein
Which of the following pacemaker cell populations has the slowest intrinsic rate of depolarization at about 20 times per minute?
Purkinje fiber system
Which wave on the electrocardiogram (ECG) represents ventricular depolarization?
QRS complex
What valve prevents the backflow of blood from the right ventricle into the right atrium?
Right atrioventricular valve (tricuspid valve)
What structure receives blood from the venae cavae?
Right atrium
The main pacemaker of the heart is the __________.
SA node
Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?
SA node
What normally serves as the pacemaker of the entire heart?
Sinoatrial (SA) node
What is the volume of blood pumped out by one ventricle per heart beat?
Stroke volume (SV)
What two values are needed to calculate cardiac output (CO) for a ventricle?
Stroke volume (SV) and heart rate (HR)
What part of an electrocardiogram (ECG) represents ventricular repolarization?
T wave
Which of the following happens immediately after the P wave?
The atria contract.
The main negative chronotropic effect on the heart is exerted by __________.
The vagus nerve's effect on the SA node slows down heart rate.
Which of the following effects will one see if there is a right-sided heart failure (failure of the right ventricle to pump adequately)?
There will be low levels of oxygen in the blood.
How is backflow of blood from the right ventricle into the right atrium prevented?
Tricuspid valve
Which of the following cardiac dysrhythmias is immediately life-threatening and manifests on the electrocardiogram (ECG) with chaotic activity?
Ventricular fibrillation
root word gram means
a recording
According to the Frank-Starling law, a bigger preload will result in __________.
a stronger contraction
the prefix epi means
above, upon, or over
electrocardiograph
an instrument used to record a person 19s heartbeat.
The P wave on an electrocardiogram (ECG) represents the depolarization of cells in the __________.
atria
the prefix inter means
between
very slow heart rate is called
bradycardia
Autorhythmicity in the heart is a function of ________.
cardiac pacemaker cells
The cusps of the atrioventricular valves attach to the papillary muscles via the __________.
chordae tendineae
Inotropic agents affect __________.
contractility
Which of the following is not an effect of the sympathetic nervous system?
decrease in heart rate
How would a decrease in blood volume affect both stroke volume and cardiac output?
decreased stroke volume and no change in cardiac output
The right side of the heart receives ________.
deoxygenated blood from the systemic circuit
What does the ECG wave tracing represent?
electrical activity in the heart
The visceral pericardium is also known as the __________.
epicardium
The visceral pericardium is the same as the ________.
epicardium
Which of the following would increase heart rate?
epinephrine and norepinephrine
High-pressured blood in the ventricles ________.
forces the semilunar valves open
electrocardiogram
graphic recording of a person 19s heartbeat.
What causes the aortic semilunar valve to close?
greater pressure in the aorta than in the left ventricle
The concentration gradient for calcium ions...
has the same direction as the concentration gradient for sodium ions.
the prefix cardi means
heart
The heart is located _________.
in the mediastinum
How would an increase in the sympathetic nervous system increase stroke volume?
increased contractility
By what mechanism would an increase in venous return increase stroke volume?
increased end diastolic volume
Which of the following would increase cardiac output to the greatest extent?
increased heart rate and increased stroke volume
endocarditits
infection of the inside lining of the heart
The apex of the heart is __________.
inferior
Unlike skeletal muscle action potentials, cardiac muscle action potentials __________.
involve calcium voltage-gated channels
Ventricular systole begins during the __________ phase of the cardiac cycle.
isovolumetric contraction
Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.
isovolumetric contraction, ventricular ejection, isovolumetric relaxation
The left ventricle is the chamber with the thickest wall, because:
it has to generate enough pressure to pump blood throughout the entire systemic circuit
Blood returning from the lungs enters the __________.
left atrium
Which heart chamber receives blood from the pulmonary veins?
left atrium
Rheumatic fever is a complication of untreated strep throat and the biggest cause of valve disorders. It can cause a condition caused aortic regurgitation in which the aortic semilunar valve is damaged and blood flows backwards into the:
left ventricle
The cardiac chamber with the thickest wall is the __________.
left ventricle
Which chamber pumps oxygenated blood out the aorta to the systemic circuit?
left ventricle
interventricular septum
located between the ventricles
myocardium
mostly made up of cardiac muscle tissue
the prefix myo means
muscle
Which of these is not a feature of cardiac muscle tissue?
non-striated
epicardium
outer layer of the heart wall
The cells that rhythmically and spontaneously generate action potentials in the heart are called __________.
pacemaker cells
The degree of stretch experienced by the sarcomeres in the ventricle cells before they contract is called __________.
preload
The AV valves close when __________.
pressure in the ventricles increases
The left side of the heart receives blood returning from the:
pulmonary circuit
Blood that leaves the right ventricle enters the __________.
pulmonary trunk
root word tachy means
quick
Which chamber receives blood from the superior and inferior vena cavae?
right atrium
Which heart chamber pumps unoxygenated blood out the pulmonary trunk?
right ventricle
The right and left atria depolarize and contract following the arrival of the action potential from the __________.
sinoatrial (SA) node
root word brady means
slow
The vessels that deliver oxygen to the tissues of the body are part of the __________.
systemic circuit
Right ventricular heart failure prevents the right ventricle from efficiently plumping blood into the pulmonary circuit, thus creating a backup of blood into the right atrium and the:
systemic veins
A very quick heart rate is called
tachycardia
The highlighted portion of this ECG trace corresponds to __________. (pwave)
the duration of atrial depolarization and AV node delay
The aortic valve closes when __________.
the pressure in the left ventricle falls below aortic pressure
root word graph means
to record
The valve located between the right atrium and the right ventricle is the:
tricuspid AV valve
Blood in the right atrium should travel next past the ________.
tricuspid valve and into the right ventricle
The heart is actually (one, two, or three) pumps?
two pumps
Both the left and right atria receive blood from ________.
veins
The right atrium receives blood from the:
vena cavae
blood from the systemic circuit returns to the heart via the __________.
venae cavae
The chambers that have just emptied when the second heart sound is heard are the __________.
ventricles
What does the QRS complex represent in the ECG wave tracing?
ventricular depolarization
Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.
ventricular diastole
The T wave of an ECG corresponds to __________.
ventricular repolarization