Chapter 17: The Heart Flashcards
the pulmonary circuit involves blood flow from the heart to and from the _____
lungs
what is the function of the valves in the heart
prevent backflow of blood through the heart
which vessel is guarded by a semilunar valve at its base?
pulmonary trunk
what vessel(s) deliver oxygenated blood to the left atrium
pulmonary veins
during what part of the action potential will calcium ions enter the contractile cell?
plateau phase
what normally serves as the pacemaker of the entire heart?
sinoatrial (SA) node
the P wave of an electrocardiogram (ECG) represents the depolarization of cells in the _____
atria
which of the following can be used to measure heart rate?
R-R interval
the amount of blood remaining in each ventricle at the end of the ventricular ejection phase is normally about __ __
50 mL
what two values are needed in order to calculate cardiac output (CO) for a ventricle?
stroke volume (SV) and heart rate (HR)
the degree of stretch experienced by the sarcomeres in the ventricle cells before they contract is called _______
preload
which of the following decreases heart rate?
acetylcholine
blood in the right atrium should travel next past the _________ _____ ___ ____ ___ _____ _________
tricuspid valve and into the right ventricle
a damaged atrioventricular (AV) bundle or atrioventricular (AV) node will primarily affect the length of the ___ ________
P-R interval
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
what is the most superficial layer of the pericardial sac?
fibrous pericardium
the visceral pericardium is the same as the __________
epicardium
both the left and right atria receive blood from _____
veins
the right side of the heart receives ____________ _____ ____ ___ ________ _______
deoxygenated blood from the systemic circuit
oxygenated blood is delivered to the left atrium through the _________ _____
pulmonary veins
which vessel is guarded by a semilunar valve at its base?
pulmonary trunk
what are three layers of the heart wall from superficial to deep?
epicardium, myocardium, and endocardium
where does the left ventricle send blood?
aorta
which blood vessel is not a great blood vessel of the heart?
pulmonary arteries
the mitral valve is the clinical name for the ________ _____
bicuspid valve
which vessel carries oxygenated blood?
pulmonary vein
what is the function of the valves in the heart?
prevent backflow of blood through the heart
what might happen if the papillary muscles and/or chordae tendinae stopped functioning?
blood would leak back into the atria from the ventricles
what statement best describes how coronary artery anastomoses might help a patient with coronary artery disease?
they provide alternate routes of blood flow when a vessel is blocked
what valve prevents the backflow of blood from the right ventricle into the right atrium?
right atrioventricular valve (tricuspid valve)
which cardiac chamber has the thickest wall?
left ventricle
what is not a function associated with the heart?
increase the rate at which erythrocytes are formed
what blood vessels do ventricles always pump blood into?
arteries
blood in the right atrium should travel next past the _________ _____ __ ____ ___ _____ _________
tricuspid valve and into the right ventricle
what statement best describes the apex of the heart
inferior tip of the heart and points toward the left side
what structure attaches the cusps of the atrioventricular valves to the papillary muscles?
chordae tendinae
what obscures atrial repolarization on an electrocardiogram (ECG)?
QRS complex
the P wave on an electrocardiogram (ECG) represents the depolarization of cells in the _____
atria
what activity is occurring in the heart during the Q-T interval on an electrocardiogram (ECG)?
the ventricular cells are undergoing action potentials
what part of an electrocardiogram (ECG) represents ventricular repolarization?
T wave
which pacemaker cell populations has the slowest intrinsic rate of depolarization at about 20 times per minute?
purkinje fiber system
which ion channels are time-gated closing channels?
calcium ion channels
what kind of ion channels are unique to pacemaker cells?
HCN channels
what allows the atria and ventricles to depolarize and contract separately?
atrioventricular (AV) node delay
what normally serves as the pacemaker of the entire heart?
sinoatrial (SA) node
what is a contractile cell with a membrane potential of 0 mV experiencing?
plateau phase
describe the total refractory period of cardiac muscle
it is longer than the total refractory period for skeletal muscle
during what part of the action potential will calcium ions enter the contractile cell?
plateau phase
what is initiated by a rapid influx of sodium ions into contractile cells creating a positive membrane potential inside the cell?
rapid depolarization phase
what cell populations does not spontaneously generate action potentials in the cardiac conduction system?
contractile cells
what structural component is only found in cardiac muscles
intercalated discs
what provides a graphic representation of all the action potentials occurring in the heart?
electrocardiogram
the right and left atria depolarize and contract following the arrival of the action potential from the __________ ____
sinoatrial (SA) node
which wave on the electrocardiogram (ECG) represents ventricular depolarization?
QRS complex
autorhythmicity in the heart is a function of _______ _________ _____
cardiac pacemaker cells
looking in a microscope, what are the visible structures that join cardiac muscle cells?
intercalated discs
which wave on the electrocardiogram
(ECG) corresponds with the ventricular filling phase of the cardiac cycle?
P wave
which of the following chemical messengers decreases heart rate?
acetylcholine
the degree of stretch experienced by the sarcomeres in the ventricle cells before they contract is called _______
preload
which term refers to the force the ventricles must overcome to eject blood into their respective arteries?
afterload
what largely determines preload?
end-diastolic volume (EDV)
which hormone decreases cardiac output by decreasing blood volume and preload?
atrial natriuretic peptide
which of the following events is not part of the cardiac cycle?
atrial contraction phase
inotropic agents affect _____________
contractility
which event can be heard most easily with a stethoscope?
closing of atrioventricular valves
what two values are needed to calculate cardiac output (CO) for a ventricle?
stroke volume (SV) and heart rate (HR)
high-pressured blood in the ventricles ______ __ _________ ______ ____
forces the semilunar valves open
which hormone decreases cardiac output by decreasing blood volume and preload?
atrial natriuretic peptide
during what phase is the S1 heart sound first heard?
isovolumetric contraction phase
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
what factor would increase cardiac output to the greatest extent?
increased heart rate and increased stroke volume
which cranial nerves have a negative chronotropic effect on heart rate?
vagus nerves (CN X)
which path does an action potential in the heart rate normally take?
sa node, atrial contractile cells, AV node where it is delayed, AV bundle right and left bundle branches, purkinje fibers, ventricular contractile cells
what is the volume of blood pumped out by one ventricle per heart beat?
stroke volume (SV)
which chamber generates the highest pressure during systole?
left ventricle
according to the frank-starling law, a bigger preload will result in _ ________ ___________
a stronger contraction
