MCQ – CARDIOLOGY

Cardiovascular physiology MCQ S

Question 1: With respect to action potential in the sino-atrial node F The resting membrane potential is more negative than for non-conducting cardiac muscle FDepolarisation is caused by activation of fast voltage gated sodium channels F There is dependence on vagal nerve stimulation for the generation of action potentials T Repolarisation is caused by increased potassium permeability

Question 2: During the cardiac cycle F The T wave occurs after the end of ventricular contraction T The a wave in the atrial pressure profile is caused by atrial contraction F The c wave in the atrial pressure profile is caused by opening of the atrio-ventricular valve T The v wave in the atrial pressure profile is caused by venous return into the

Question 3: During the cardiac cycle F Atrial contraction occurs during systole T The P wave of the electrocardiogram represents atrial depolarisation F The QRS complex represents ventricular repolarisation F The T wave represents ventricular depolarisation

Question 4: Vasodilatation is caused by F Increased pH T Increased osmolarity T Increased CO2 concentration F Increased oxygen tension

Question 5: The following are associated with a decrease in cardiac output F Increased blood volume T Acute venous dilatation T Venous obstruction F Blood pressure of 160/100

Question 6: During the cardiac cycle T The v wave in the atrial pressure profile is caused by venous return into the atrium T The notch in the aortic pressure profile is caused by closure of the aortic valve F The first heart sound is caused by opening of the atrio-ventricular valves T The second heart sound is caused by closure of the aortic and pulmonary Valves

Question 7: With respect to the conducting system of the heart F The refractory period of the atrioventricular node is shorter than for normal cardiac muscle fibres F The sinoatrial node has an intrinsic rhythmic rate of 40-60 per minute T The atrioventricular node has an intrinsic rhythmic rate of 40-60 per minute T The Purkinje fibres have an intrinsic rhythmic rate of 15-40 per minute

Question 8: With respect to autonomic control of the heart F Vagal stimulation has no effect on the rate of the rhythm of the sinoatrial node T Vagal stimulation decreases the excitability of the atrio-ventricular junctional fibres T Sympathetic stimulation increases the rate of the rhythm of the sinoatrial node F Sympathetic stimulation decreases the strength of myocardial contraction

Question 9: The following are important mechanisms in the short-term maintenance of arterial pressure following haemorrhage

T Peripheral vasoconstriction F Increased fluid retention by the kidneys T Increased heart rate F Increased venous return

Question 10: The following are produced locally in tissues and regulate perfusion T Prostaglandins T Serotonin F Adrenaline F Noradrenaline

Question 11: With respect to the conducting system of the heart T The sinoatrial node is the natural pacemaker T Impulses are conducted from the sinoatrial node to the atrioventricular node by three internodal pathways F Impulses are conducted from the right atrium to the left atrium by the Purkinje fibres T There is a delay in the conduction of cardiac impulses at the atrioventricular node

Question 12: During the cardiac cycle F Pressure in the left ventricle must rise above 120mmHg to cause opening of the aortic valve F The period of rapid ejection occupies the first 70% of ventricular ejection time T The normal PR interval is about 0.16s F The QT interval is the duration of ventricular relaxation

Question 13: Mean arterial pressure T Is the average arterial pressure over a cardiac cycle F Can be calculated from ½ (systolic minus diastolic pressure) T Can be calculated from diastolic pressure + 1/3(pulse pressure) F Can be calculated from the cardiac output X total peripheral resistance

Question 14: The following are associated with a decrease in cardiac output F Pregnancy F Anaemia T Haemorrhage F Hyperthyroidism

Question 15: During the cardiac cycle F Blood flows into the atria only during atrial diastole F Atrial contraction contributes 70% to ventricular filling F Blood flows from the atria into the ventricles during systole F Ventricular ejection occurs during the period of isometric contraction