a. Start of the R wave to end of T wave
Which of the following is least likely to regulate the heart rate?
a. Intermedio-lateral (lateral) nucleus
b. Sinu-atrial node
c. Cardiac (nerve) plexus
d. Phrenic nerve
e. Vagus nerve
d. Phrenic nerve
Which of the following statements is FALSE about the autonomic innervation of the heart?
a. At the preganglionic synapse for parasympathetic innervation, acetylcholine is released from the preganglionic neuron
b. At the postganglionic synapse for parasympathetic innervation, acetylcholine is released from the postganglionic neuron
c. At the postganglionic synapse for sympathetic innervation, noradrenaline (norepinephrine) is released from the postganglionic neuron
d. Postganglionic neurons are located in cervical ganglia
e. Postganglionic neurons run in the vagus nerve
e. Postganglionic neurons run in the vagus nerve
Which of the following is an indication of increased ventricular contractility?
a. Increase end-diastolic volume, same end-systolic volume
b. Decrease end-diastolic volume, same end-systolic volume
c. Increase end-systolic volume, same end-diastolic volume
d. Decrease end-systolic volume, same end-diastolic volume
e. Increase end-diastolic volume, increase end-systolic volume
d. Decrease end-systolic volume, same end-diastolic volume
b. Decrease heart rate
The following would be observed in a patient in hypovolemic shock except:
a. Sweating (increased sympathetic innervation)
b. Decreased urine output (ADH / aldosterone)
c. Higher central venous pressure
d. Increased plasma aldosterone concentration
e. Increased total peripheral resistance
c. Higher central venous pressure
a. Lower blood pressure
Which of the following is not indicative of heart failure?
a. Exertional dyspnea
b. Ankle edema
c. Increased ejection fraction
c. Increased ejection fraction
a. The rate of ventricular contraction will decrease
c. There would be more P waves than QRS complexes
What effect would compressing the inferior vena cava just below the diaphragm have on cardiac function?
a. Stroke volume would decrease
b. Cardiac output would decrease
c. Sympathetic stimulation of the heart would eventually increase
d. Heart rate would eventually increase
e. All of the above
e. All of the above
According to the Frank-Starling Law of the heart, CO is directly related to:
a. Ventricular muscle mass
b. Heart rate
c. Amount of blood returning to the heart
d. ESV
e. Cardiac reserve
c. Amount of blood returning to the heart
The T wave on an ECG represents:
a. Ventricular depolarization
b. Ventricular repolarization
c. Atrial depolarization
d. Atrial repolarization
e. Ventricular systole
b. Ventricular repolarization
f. 2 of the above
The left ventricular wall is thicker than the right ventricular wall in order to:
a. Accommodate a greater volume of blood
b. Expand the thoracic cage during diastole
c. Pump a greater volume of blood
d. Pump blood with greater pressure
e. Pump blood through a smaller valve
d. Pump blood with greater pressure
If the vagal nerves to the heart were cut, the result would be that:
a. The heart would stop
b. The heart rate would decrease
c. The heart rate would increase
d. Parasympathetic stimulation to the blood vessels would increase in an attempt to compensate
c. The heart rate would increase
Which of the following depolarizes next after the AV node:
a. Atrial myocardium
b. Ventricular myocardium
c. Bundle branches
d. Purkinje fibers
c. Bundle branches
Given an EDV of 150 ml, an ESV of 50 ml and a HR of 60 bpm, cardiac output is:
a. 600 ml/min
b. 6 l/min
c. 60000 ml/min
d. none of the above
b. 6 l/min
The statement “strength of contraction increases intrinsically due to increased stretching of the heart wall” is best attributed to:
a. Poiusseille’s law
b. Bainbridge reflex
c. Frank-Starling law
d. Faraday’s law
e. Henry’s law
c. Frank-Starling law
An increase in heart rate will cause preload to
a. Increase
b. Decrease
c. Stay the same
b. Decrease
d. All of the above
During atrial systole
a. The tricuspid and bicuspid valves are closed but the semilunar valves are open
b. The bicuspid valve is open but the mitral valve is closed
c. Both semilunar valves and both AV valves are open
d. Both AV valves are open and both semilunar valves are closed
d. Both AV valves are open and both semilunar valves are closed
A variety of events occur in the cardiac cycle when the semilunar valves are open. Select the letter answer that contains all the correct numbered events.
a. 1, 2, 3, 4, 5, 6
b. 1, 2, 4, 5, 6
c. 4, 5
d. 4, 5, 6
e. None of the above
b. 1, 2, 4, 5, 6
An ECG has no P waves but QRS and T wave are normal. Which of the following is the most likely pacemaker?
a. SA node
b. AV node
c. Bundle branch
d. Purkinje fibres
e. Myocardium
b. AV node