Ch 20 Flashcards
The region between the two pleural cavities that contains the heart and great vessels is called the ______.
a. mediastinum
b. visceral pericardium
c. parietal pericardium
d. pericardial cavity
a. mediastinum
Which layer of pericardium touches the heart?
a. parietal pericardium
b. pericardial sac
c. fibrous pericardium
d. visceral pericardium
d. visceral pericardium
Which of the following is true of cardiac muscle tissue?
a. Cardiac muscle cells are larger than skeletal muscle cells.
b. Cardiac muscle is not striated.
c. Cardiac muscle cells have intercalated discs.
d. Cardiac muscle cells are multin
c. Cardiac muscle cells have intercalated discs.
Why is the left ventricle more muscular than the right ventricle?
a. It pumps a larger volume of blood.
b. It contracts with force sufficient to push blood through the systemic circuit.
c. The papillary muscles are stronger.
d. Both A and B are correct.
b. It contracts with force sufficient to push blood through the systemic circuit
Where is the ANS headquarters for cardiovascular control?
a. cardiac plexus
b. SA and AV nodes
c. medulla oblongata
d. cervical and upper thoracic ganglia
c. medulla oblongata
What is the importance of the 100-msec delay at the AV node?
a. Atria must contract to fill the ventricles with blood.
b. AV valves must have time to close slowly.
c. Semilunar valves must have time to close slowly.
d. Tachycardia results if the delay is absent.
a. Atria must contract to fill the ventricles with blood.
Why is resting HR somewhat slower than the
80–100 bpm set by the SA node?
a. The AV node slows the heart to an average between its own rate and that of the SA node.
b. Parasympathetic effects dominate in a resting individual.
c. Sympathetic fibers release NE to slow heart rate.
d. Both A and B are correct.
b. Parasympathetic effects dominate in a resting individual
How is cardiac output (CO) calculated?
a. CO mL/min = (EDV – ESV) × HR
b. CO mL/min = HR bpm × SV mL/beat
c. CO mL/min = ESV/EDV
d. both A and B
d. both A and B
During ventricular systole of the cardiac cycle, all of the following would occur EXCEPT _____.
a. rising ventricular blood pressure would exceed aortic pressure
b. all heart valves would be closed
c. atrial diastole would occur as both the atria fill
d. pressure in ventricles would force the semilunar valves closed
d. pressure in ventricles would force the semilunar valves closed
When during the cardiac cycle do ventricles contain their maximal amount of blood? What is this quantity called?
a. at the end of ventricular systole; ESV
b. at the end of atrial systole; EDV
c. at the end of ventricular diastole; EDV
d. both B and C
d. both B and C
On an ECG reading, what does the P wave indicate?
a. ventricular contraction
b. an abnormal heart condition
c. atrial depolarization
d. atrial diastole
c. atrial depolarization
What event is taking place during the Q–T interval?
a. a single cycle of the cardiac cycle
b. an action potential
c. a single cycle of atrial depolarization and repolarization
d. a single cycle of ventricular depolarization and repolari
d. a single cycle of ventricular depolarization and repolarization
What factor could cause an increase in the size of the QRS complex of an electrocardiogram recording?
a. an increase in heart rate
b. a decrease in blood volume
c. a decrease in blood pressure
d. an increase in heart size
d. an increase in heart size
What condition contributes to a reduction in the size of the T wave?
a. long-term high fat intake
b. damage to the conduction pathway
c. damage to the AV node
d. coronary ischemia
d. coronary ischemia
Why is there no wave corresponding to atrial repolarization on an ECG reading?
a. It is masked by the QRS complex.
b. Atrial repolarization produces no electrical effect at all.
c. It is masked by the P wave.
d. None of the above is correct
a. It is masked by the QRS complex.