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प्रश्न
Explain the conduction of heartbeat.
उत्तर
Conduction of heartbeat: The heart in human is myogenic. The cardiac cells with the fastest rhythm are called the pacemaker cells. These cells are located in the right sino-atrial node. The impulse from the sino-atrial node. spreads like a wave of contraction over the right and left atrial wall pushing the blood through the atrioventricular valves into the ventricle. Two special cardiac muscles fibres originate from the auriculo ventricular node and are called the bundle of his which runs down into the interventricular septum and the fibres spread into the ventricles. These fibres are called the Purkinje.
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Match the parts of the heart in Column I with the direction of the flow of blood in Column II.
| Column I | Column II | ||
| (i) | Right ventricle | (a) | Pushes blood into the pulmonary artery. |
| (ii) | Pulmonary veins | (b) | Take deoxygenated blood from the heart to the lungs. |
| (iii) | Left atrium | (c) | Receives blood from different parts of the body. |
| (iv) | Pulmonary arteries | (d) | Bring oxygenated blood from the lungs to the heart. |
| (v) | Left ventricle | (e) | Pushes blood into the aorta. |
| (vi) | Right auricle | (f) | Receives deoxygenated blood from the pulmonary veins. |
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