Cardiovascular System
Which one of the following descriptions or statements about an electrocardiogram (ECG) is NOT correct?
It is a record of the voltage changes (as measured at the body surface) due to the depolarisation of the muscle cells of the heart as it beats.
The potentials measured by the ECG electrodes are combined in various ways to give 12 different ECGs.
The ECG consists of the electrical events that follow the depolarisation of ventricles (PQR section), the depolarisation of atria (the S section) and the repolarisation of the ventricles (the T section).
The value of the potential difference called “limb lead II” varies with time to produce the familiar ECG trace โ a graph of voltage vs time.
The ECG consists of the electrical events that follow the depolarisation of ventricles (PQR section), the depolarisation of atria (the S section) and the repolarisation of the ventricles (the T section).
The ECG also displays the depolarisation of the atria (the P wave); the depolarisation of the ventricles results in the QRS wave โ not the PQR wave.
The ECG consists of the electrical events that follow the depolarisation of ventricles (PQR section), the depolarisation of atria (the S section) and the repolarisation of the ventricles (the T section). The ECG also displays the depolarisation of the atria (the P wave); the depolarisation of the ventricles results in the QRS wave โ not the PQR wave.
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By what name is the heart muscle known?A. Epicardium
B. Myocardium
C. Pericardium
D. Endocardium
Which statement about cardiac output is correct?
A. Cardiac output is peripheral resistance multiplied by stroke volume.
B. Mean arterial pressure multiplied by peripheral resistance is cardiac output.
C. Cardiac output is heart rate multiplied by stroke volume.
D. Cardiac output is blood volume multiplied by heart rate.
What is “systolic pressure”?
A. The peak pressure in the blood due to contraction of the left ventricle.
B. The minimum pressure in the blood prior to contraction of the left ventricle.
C. It may be obtained by multiplying cardiac output by total peripheral resistance.
D. It is also known as mean arterial pressure.
A statement of Boyle’s law could be:
A. As pressure of a gas increases, its solubility increases.
B. As volume of a gas increases, its pressure decreases.
C. As volume of a gas decreases, its pressure decreases.
D. As pressure of a gas increases, its solubility decreases.
Which of the following is not a type of white blood cell?
A. Leucocyte
B. Eosinophil
C. Erythrocyte
D. Neutrophil
Consider Boyle’s law. If the pressure being exerted on an enclosed volume of gas (at a constant temperature) is increased by 20%, by what percentage would its volume change?
A. Volume would increase by 20%.
B. Volume would increase by 44%.
C. Volume would decrease by 44%.
D. Volume would decrease by 20%.
Through which valve does blood flow when it moves from the left atrium into the left ventricle?
A. The semilunar valve
B. The mitral valve
C. The tricuspid valve
D. The aortic valve
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