Mastering A&P Chapter 17.
P-R interval
A damaged atrioventricular (AV) bundle or AV node will primarily affect the length of the __________.
a stronger contraction
According to the Frank-Starling law, a bigger preload will result in _____
70 ml
Approximately how much blood is pumped from each ventricle during the ventricular ejection phase?
cardiac pacemaker cells
Autorhythmicity in the heart is a function of ________.
tricuspid valve and into the right ventricle
Blood in the right atrium should travel next past the ________.
veins
Both the left and right atria receive blood from ________.
40 ml
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.
Plateau phase
During what part of the action potential will calcium ions enter the contractile cell?
Isovolumetric contraction phase
During what phase is the S1 heart sound first heard?
forces the semilunar valves open
High-pressured blood in the ventricles _______
forces the semilunar valves open
High-pressured blood in the ventricles ________.
contractility
Inotropic agents affect __________.
Intercalated discs
Looking in a microscope, what are the visible structures that join cardiac muscle cells?
pulmonary veins
Oxygenated blood is delivered to the left atrium through the ____________.
atria
The P wave on an electrocardiogram (ECG) represents the depolarization of cells in the
preload
The degree of stretch experienced by the sarcomeres in the ventricle cells before they contract is called
bicuspid valve
The mitral valve is the clinical name for the ______________.
sinoatrial (SA) node
The right and left atria depolarize and contract following the arrival of the action potential from the __________.
deoxygenated blood from the systemic circuit
The right side of the heart receives ________.
epicardium
The visceral pericardium is the same as the ________.
The ventricular cells are undergoing action potentials.
What activity is occurring in the heart during the Q-T interval on an electrocardiogram (ECG)?
Atrioventricular (AV) node delay
What allows the atria and ventricles to depolarize and contract separately?
Epicardium, myocardium, and endocardium
What are the three layers of the heart wall from superficial to deep?
Arteries
What blood vessels do ventricles always pump blood into?
Bradycardia
What cardiac dysrhythmia does a patient have with a resting heart rate of 50 beats per minute?
Cardiac tamponade
What condition results from excess fluid in the pericardial cavity compressing the heart and reducing the capacity of the ventricles to fill with blood?
Plateau phase
What is a contractile cell with a membrane potential of 0 mV experiencing?
Rapid depolarization phase
What is initiated by a rapid influx of sodium ions into contractile cells creating a positive membrane potential inside the cell?
What is the function of the valves in the heart?
What is the function of the valves in the heart?
Fibrous pericardium
What is the most superficial layer of the pericardial sac?
Stroke volume (SV)
What is the volume of blood pumped out by one ventricle per heart beat?
HCN
What kind of ion channels are unique to pacemaker cells?
HCN channels
What kind of ion channels are unique to pacemaker cells?
End-diastolic volume (EDV)
What largely determines preload?
Blood would leak back into the atria from the ventricles.
What might happen if the papillary muscles and/or chordae tendineae stopped functioning?
Sinoatrial (SA) node
What normally serves as the pacemaker of the entire heart?
QRS complex
What obscures atrial repolarization on an electrocardiogram (ECG)?
T wave
What part of an electrocardiogram (ECG) represents ventricular repolarization?
80%
What percentage of atria blood flows passively into the ventricles?
1%
What percentage of the total number of cardiac muscle cells are pacemaker cells?
EKG
What provides a graphic representation of all the action potentials occurring in the heart?
Chordae tendineae
What structure attaches the cusps of the atrioventricular valves to the papillary muscles?
Stroke volume (SV) and heart rate (HR)
What two values are needed to calculate cardiac output (CO) for a ventricle?
Right atrioventricular valve (tricuspid valve)
What valve prevents the backflow of blood from the right ventricle into the right atrium?
Aorta
Where does the left ventricle send blood?
Left ventricle
Which cardiac chamber has the thickest wall?
Left ventricle
Which chamber generates the highest pressure during systole?
Circumflex artery
Which coronary artery supplies the left atrium and parts of the left ventricle?
Vagus nerves (CN X)
Which cranial nerves have a negative chronotropic effect on heart rate?
R-R interval
Which electrocardiogram (ECG) finding can be used to measure heart rate?
Atrial natriuretic peptide
Which hormone decreases cardiac output by decreasing blood volume and preload?
Great cardiac
Which of the following blood vessels are associated with the coronary sinus?
Pulmonary arteries
Which of the following blood vessels is not a great blood vessel of the heart?
V fib
Which of the following cardiac dysrhythmias is immediately life-threatening and manifests on the electrocardiogram (ECG) with chaotic activity?
Ventricular fibrillation
Which of the following cardiac dysrhythmias is immediately life-threatening and manifests on the electrocardiogram (ECG) with chaotic activity?
Contractile cells
Which of the following cell populations does not spontaneously generate action potentials in the cardiac conduction system?
Acetylcholine
Which of the following chemical messengers decreases heart rate?
Closing of atrioventricular valves
Which of the following events can be heard most easily with a stethoscope?
Atrial contraction phase
Which of the following events is not part of the cardiac cycle?
Increased heart rate and increased stroke volume
Which of the following factors would increase cardiac output to the greatest extent?
To increase the rate at which erythrocytes are formed
Which of the following functions is not associated with the heart?
Atrial natriuretic peptide
Which of the following hormones decrease cardiac output by decreasing blood volume and preload?
Calcium ion channels
Which of the following ion channels are time-gated closing channels?
Low blood pressure
Which of the following is not a risk factor for coronary artery disease or myocardial ischemia?
Purkinje fiber system
Which of the following pacemaker cell populations has the slowest intrinsic rate of depolarization at about 20 times per minute?
SA node atrial contractile cells AV node where it is delayed AV bundle right and left bundle branches Purkinje fibers ventricular contractile cells
Which of the following paths does an action potential in the heart normally take?
They provide alternate routes of blood flow when a vessel is blocked.
Which of the following statements best describes how coronary artery anastomoses might help a patient with coronary artery disease?
Inferior tip of the heart and points toward the left side
Which of the following statements best describes the apex of the heart?
It is longer than the total refractory period for skeletal muscle.
Which of the following statements describes the total refractory period of cardiac muscle?
Intercalated discs
Which of the following structural components is only found in cardiac muscles?
Pectinate muscles
Which of the following structures is associated with the atria?
Afterload
Which of the following terms refers to the force the ventricles must overcome to eject blood into their respective arteries?
Pulmonary vein
Which of the following vessels carries oxygenated blood?
Fossa ovalis
Which opening in the interatrial septum of the fetal heart connects the right and left atrium?
Pulmonary trunk
Which vessel is guarded by a semilunar valve at its base?
P wave
Which wave on the electrocardiogram (ECG) corresponds with the ventricular filling phase of the cardiac cycle?
QRS complex
Which wave on the electrocardiogram (ECG) represents ventricular depolarization?
