Question

2 Physiology of the Heart he was in wahren in A Pins the answer Column Column A Angina pector L. Anne of the cercalativity B. Bradycardia 2. The pred when the rare depolar C. Hectrocarde D. Fibrillation E Heart block The period when the ventricles are real The period during which the ventricles are depolarising, which precedes their contraction FP wave G. QRS wave 5. An abnormally slow heartbeat, that is, slower than 60 beats per minute HT Wave I Tachycardia 6. A condition in which the heart is uncoordinated and useless as a pump 7. An abnormally rapid heartbeat, that is, faster than 100 beats per minute & Damage to the AV node, totally or partially releasing the ventricles from the control of the sinoatrial (SA) node 9. Chest pain, resulting from ischemia of the myocardium 8. A portion of an electrocardiogram is shown in Figure 11-5. On the figure identify the OS complex, the P wave, and the T wave. Then, using a red pencil, bracket a portion of the recording equivalent to the length of one car diac cycle. Lising a blue pencil, bracket a portion of the recording in which the switches would be in diastole. Figure 11-5

Answer 1

The recording of the electrical activity of the heart using surface electrodes is called Electrocardiogram (ECG). The normal ECG consists of a P wave, QRS complex and the T wave.

R Pwave T wave S NORMAL ECG one cardiac cycle

The P wave correspond to the depolarisation of the atria. The QRS complex corresponds to the deparisation of the ventricles. The repolarisation of the ventricles is represented by the T wave. The repolarisation of atria merges with the ventricular depolarisation - in the QRS complex.

The normal heart rate is 60 - 100 beats per minute. An abnormally slow heart rate less than 60 beats per minute is called bradycardia. An abnormally fast heart rate more than 100 beats per minute is called tachycardia.

Atrial fibrillation - Irregular and uncoordinated contractions of individual heart-muscle fibers is called atrial fibrillation. Here, the atria contracts at an abnormally fast rate, but effective contraction does not take place.

The impulse generated by the SA node is transmitted to the AV node which then carries the impulse to the ventricles via the bundle of His and purkinje fibres. Sometimes, a a damage to the AV node can impair this impulse conduction - known as heart block.

The heart is supplied by arteries called coronary arteries. Sometimes block / occlusion of these arteries can impair the blood supply to the haert causing ischemia of the myocardium resulting in severe pain called Angina pectoris.

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Answers

1. A recording of the electrical activity of the heart - Electrocardiogram

2. The period when atria are depolarising - P wave

3. The period when ventricles are repolarising - T wave

4. The period during which the ventricles are depolarising, which precedes their contraction - QRS wave

5. An abnormally slow heartbeat < 60 bpm - Bradycardia.

6. A condition in which the heart is uncoordinated and useless as a pump - Fibrillation

7. An abnormally rapid heartbeat > 100 bpm - Tachycardia.

8. Damage to the AV node, totally or partially, releasing the ventricles from the SA node - Heart block

9. Chest pain, resulting from ischemia of the myocardium - Angina pectoris.