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Question 01

Regarding the conduction system of the heart:

a) Between action potentials, the cells of the sino-atrial node have a steady resting potential.

b) The cardiac action potential is conducted through the atria via Purkinje fibers.

c) The Purkinje fibers are specialized cardiac myocytes linked by gap junctions.

d) The spread of cardiac excitation speeds up at the atrio-ventricular node.

Question 02

Regarding the ECG:

a) The P wave of the ECG reflects atrial contraction.

b) The P-Q interval is normally about 0.1s.

c) The QRS complex reflects the start of ventricular contraction.

d) The peak amplitude of the ECG recorded by the limb leads is about 10 mV.

Question 03

During the cardiac cycle of a normal healthy young adult:

a) During ventricular diastole the pressure in the left ventricle is close to 80 mm Hg (10.6 kPa).

b) During ventricular systole, the pressure in the left ventricle reaches a maximum of about 25 mm Hg (3.3 kPa).

c) During the initial stage of ventricular contraction the volume of the ventricle does not change.

d) During ventricular systole, all the blood in the ventricles is ejected.

Question 04

Concerning the normal heart sounds:

a) The first heart sound corresponds with the closure of the mitral and tricuspid valves.

b) The first heart sound occurs just before the R wave of the ECG.

c) The first heart sound is split into two components during inspiration.

d) The second heart sound occurs during the T-wave.

Question 05

The cardiac output:

a) Is increased by aldosterone released from the adrenal medulla.

b) Is increased by stimulation of the vagus nerve.

c) Can be measured by dividing the oxygen consumption by the difference in PO₂ of the venous and arterial blood.

d) Is largely determined by the end-diastolic volume.

Question 06

The arterial blood pressure:

a) Is 120/80 mm Hg (16/10.6 kPa).

b) Depends solely on the cardiac output.

c) Is the arithmetic average of the systolic and diastolic pressures.

d) Is due to the vascular resistance of the capillaries.

Question 07

Concerning the control of the vasculature:

a) Autoregulation refers to the nervous control of the blood vessels.

b) Reactive hyperemia is due to vasodilatation caused by accumulation of metabolites during a period of exercise.

c) Parasympathetic vasodilator fibers innervate the blood vessels of the exocrine glands of the gastro-intestinal tract.

d) The diameter of the arterioles is entirely regulated by the sympathetic nervous system.

Question 08

Concerning the microcirculation:

a) The exchange of solutes between the capillaries and tissues occurs mainly by bulk flow.

b) The capillaries provide a significant source of vascular resistance.

c) All of the fluid that passes from the capillaries to the tissues is returned to the blood via the lymphatic circulation.

d) The plasma proteins play an important role in tissue fluid exchange.

Question 09

Concerning the nervous regulation of the circulation:

a) The baroreceptors are mainly responsible for the long-term regulation of systemic blood pressure.

b) If the arterial pressure suddenly falls the baroreceptor reflex increases the heart rate.

c) The baroreceptors are found in the aortic and carotid bodies.

d) The coronary blood flow is regulated by the cardiac volume receptors.

Oxford University Press, Online Resource Centre, Chapter 15.

Chapter 15

Instructions