Chapter 17 review Mastering A&P II
Place the following parts of the cardiac conduction system in the order in which they transmit the action potential. 1. atrioventricular (AV) bundle 2. Purkinje fibers 3. sinoatrial (SA) node 4. right and left bundle branches 5. contractile cells of cardiac muscle tissue 6. atrioventricular (AV) node
3, 6, 1, 4, 2, 5
Calculate the stroke volume (SV) if end-systolic volume (ESV) is 50 ml and the end-diastolic volume (EDV) in a resting heart is 110 ml.
60 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 heartbeat
A damaged atrioventricular (AV) bundle or atrioventricular (AV) node will primarily affect the length of the:
P-R interval
On an electrocardiogram (ECG), atrial repolarization is obscured by the:
QRS wave
Which of the following can be used to measure heart rate?
R-R interval
What wave on the electrocardiogram (ECG) occurs during the ventricular ejection phase of the cardiac cycle?
T wave
What activity is occurring in the heart during the Q-T interval on an electrocardiogram (ECG)?
The ventricular cells are undergoing action potentials.
The long length of the cardiac action potential, at 200-300 msec, allows for
an opportunity for the heart to fill with blood
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 P wave 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 (ANP)
Which valve is situated between the left atrium and left ventricle?
bicuspid (mitral) valve
The coronary sinus does NOT receive blood from the:
brachiocephalic vein
Which of the following volumes should be the greatest?
cardiac output
The visceral pericardium is the same as the:
epicardium
Coronary circulation involves the delivery of oxygenated blood to the:
heart
What ion movement changes the membrane potential in a contractile cell from negative to positive during the rapid depolarization phase?
influx of sodium ions
When is the S2 heart sound heard?
isovolumetric relaxation phase
An insufficient mitral valve (bicuspid valve, or left atrioventricular valve) would allow the backflow of blood into the:
left atrium
The cardiac chamber with the thickest wall is the
left ventricle
Which chamber experiences a maximum pressure of around 118 mm Hg during contraction?
left ventricle
Which of these is not a feature of cardiac muscle tissue?
non- striated
Which of the following is NOT a population of pacemaker cells in the heart?
papillary muscles
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
Which of the following does NOT return blood to the right atrium of the heart?
pulmonary vein
What vessel(s) deliver oxygenated blood to the left atrium?
pulmonary veins
Blood in the right ventricle arrived from the:
right atrium
The right and left atria depolarize and contract following the arrival of the action potential from the:
sinoatrial (SA) node
What normally serves as the pacemaker of the entire heart?
sinoatrial (SA) node
Archie has a resting heart rate of 125 beats per minute. Classify his cardiac dysrhythmia
tachycardia
What valve prevents the backflow of blood from the right ventricle into the right atrium?
tricuspid valve
Which cranial nerves have a negative chronotropic effect on heart rate?
vagus nerves
