Chapter 17 TB Question
Which cranial nerves have a negative chronotropic effect on heart rate ?
vagus nerves ( CN X )
Both the left and right atria receive blood from :
veins
During what phase does blood flow from the ventricles into the pulmonary trunk and aorta ?
ventricular ejection phase
End - diastolic volume for each ventricle during rest is normally about
120 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 .
40 ml
The amount of blood remaining in ceach ventricle at the end of the ventricular ejection phase is normally about
50 ml
Calculate the cardiac output if the heart rate is 100 beats per minute and the stroke volume is 65 ml .
6500 ml / min
How much blood is pumped from each ventricle during the ventricular ejection phase ?
70 ml
Stroke volume averages about :
70 ml per heart beat
Predict the position of the valves when the ventricles contract
Both AV valves are forced shut while both semilunar valves are forced open
How do cardiac cells sustain a membrane potential of around 0 mV during the long plateau phase ?
Calcium channels remain open
Coronary circulation involves the delivery of oxygenated blood to the
Heart
The pulmonary circuit involves blood flow from the heart to and from the
Lungs
A damaged atrioventricular ( AV ) bundle or atrioventricular ( AV ) node will primarily affect the length of the
P Wave
Which wave on the electrocardiogram ( ECG ) corresponds with the ventricular filling phase of the cardiac cycle ?
P wave
A damaged right bundle branch will prevent the passage of the action potential to the
Purkinje fibers in the right ventricle
Which part of the electrocardiogram ( ECG ) would most be affected by abnormally slow depolarization of the ventricles ?
QRS Wave
On an electrocardiogram ( ECG ) , atrial repolarization is obscured by the
QRS wave
Which wave on the electrocardiogram ( ECG ) represents ventricular depolarization ?
QRS wave
Which of the following can be used to measure heart rate ?
R - R interval
What valve prevents the backflow of blood from the right ventricle into the right atrium ?
Right atrioventricular valve ( tricuspid valve )
Place the following parts of the cardiac conduction system in the order in which they transmit the action potential .
Sinoatrial (SA) node, atrioventricular (AV) node, atrioventricular (AV) bundle, right and left bundle branches, Purkinje fibers, contractile cells of cardiac muscle tissue
What wave on the electrocardiogram ( ECG ) occurs during the ventricular ejection phase of the cardiac cycle ?
T wave
What best describes the Frank - Starling law ?
The Frank - Starling law states that the more the ventricular muscle cells are stretched , the more forcefully they contract .
Determine the impact if the connection between the sinoatrial ( SA ) node and the atrioventricular ( AV ) node becomes blocked .
The ventricles will beat more slowly .
What activity is occurring in the heart during the Q - T interval on an electrocardiogram ( ECG ) ?
The ventricular cells are undergoing action potentials
Which of the following decreases heart rate ?
acetylcholine
The right and left coronary arteries receive blood from the
aorta
What vessel delivers oxygenated blood to systemic capillaries for gas exchange ?
aorta
Where should the left ventricle send blood ?
aorta
Which vessel supplies the systemic circuit with oxygenated blood ?
aorta
The Pwave on an electrocardiogram ( ECG ) represents the depolarization of cells in the
atria
Which hormone decreases cardiac output by decreasing blood volume and preload ?
atrial natriuretic peptide
What is NOT part of the cardiac conduction system ?
atrioventricular ( AV ) valve
The coronary sinus does NOT receive blood from the
brachiocephalic vein
Autorhythmicity is the responsibility of
cardiac pacemaker cells
The cusps of the atrioventricular valves attach directly to :
chordae tendineae
Inotropic agents affect :
contractility
Generally , coronary veins empty into a vessel known as the
coronary sinus
The right side of the heart receives :
deoxygenated blood from the systemic circuit
What largely determines preload ?
end - diastolic volume ( EDV )
Which of the following volumes should be the greatest ?
end - diastolic volume ( EDV )
The visceral pericardium is the same as the
epicardium
What is the most superficial layer of the pericardial sac ?
fibrous pericardium
Which opening in the interatrial septum of the fetal heart connects the right and left atrium ?
foramen ovale
High pressured blood in the ventricles :
forces the semilunar valves open
What ion movement changes the membrane potential in a contractile cell from negative to positive ?
influx of sodium ions
What characteristic differentiates cardiac muscle cells from skeletal muscle cells ?
intercalated discs
What surface groove separates the right and left ventricles ?
interventricular sulcus
When is the SI heart sound heard ?
isovolumetric contraction phase
An insufficient mitral valve ( bicuspid valve , or left atrioventricular valve ) would allow the backflow of blood into the
left atrium
The apex of the heart is situated toward the
left hip
Which chamber experiences a maximum pressure of around 118 mm Hg during contraction ?
left ventricle
The heart is situated in the middle of the thoracic cavity in a region known as the
mediastinum
What muscles , present in the ventricles , anchor by tendon n - - like like chords chords called d chordac chordac tendineae ?
papillary muscles
Which of the following is NOT a population of pacemaker cells in the heart ?
papillary muscles
What is found between the visceral pericardium and the parietal pericardium ?
pericardial fluid
A contractile cell with a membrane potential of 0 mV is experiencing the
plateau phase
During what part of the action potential will calcium ions enter the contractile cell ?
plateau phase
The length of the cardiac action potential , at 200-300 msec , is dependent upon the
plateau phase
What do pacemaker cell action potentials lack ?
plateau phase
The degree of stretch experienced by the sarcomeres in the ventricle cells before they contract is called:
preload
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 vein
Which of the following does NOT return blood to the right atrium of the heart ?
pulmonary vein
Which of the following vessels carries oxygenated blood ?
pulmonary vein
The rapid influx of sodium ions into contractile cells creates a positive membrane potential inside the cell and initiates the
rapid depolarization phase
What normally serves as the pacemaker of the entire heart ?
sinoatrial (SA) node
Which of the following pacemaker cell populations has the fastest intrinsic rate of depolarization at about 60 times per minute ?
sinoatrial (SA) node
The right and left atria depolarize and contract following the arrival of the action potential from the :
sinoatrial SA ) node
The volume of blood pumped by each ventricle in one heartbeat is known as :
stroke volume ( SV )
What two values are needed in order to calculate cardiac output ( CO ) for a ventricle ?
stroke volume ( SV ) and heart rate ( HR )
Archie has a resting heart rate of 125 beats per minute . Classify his cardiac dyshythmia
tachycardia
As a result of the long refractory period in the contractile cell refractory period , cardiac muscle can NOT exhibit :
tetany
Afterload is described as :
the force the ventricles must overcome to eject blood into their respective arteries
Which two arteries arise from the right coronary artery ?
the right marginal artery and the right posterior interventricular artery
What produces the " lub dub " heart sounds ? the contraction of
the vibrations of the ventricular and blood vessel walls when valves shut
Blood in the right atrium should travel next past the :
tricuspid valve and into the right ventricle
