SELECT * FROM question_mgmt as q WHERE id=353 AND status=1 SELECT id,question_no,question,chapter FROM question_mgmt as q WHERE courseId=2 AND subId=7 AND chapterId=21 and ex_no='1' AND status=1 ORDER BY CAST(question_no AS UNSIGNED) CBSE Free NCERT Solution of 11th biology Body Fluids and Circulation draw a standard ecg and explain the different segm

Question: Draw a standard ECG and explain the different segments in it.

Answer:

Electrocardiogram is a graphical representation of the cardiac cycle produced by an electrograph. The diagrammatic representation of a standard ECG is shown below.

                                     standard ECG

A typical human electrocardiogram has five waves – P, Q, R, S, and T. The P, R, and T-waves are above the base line and are known as positive waves. The Q and S-waves are below the base line and are known as negative waves. The P-wave is of atrial origin, while the Q, R, S, and T-waves are of ventricular origin. 

(a) The P-wave indicates atrial depolarisation. During this wave, the impulse of contraction is generated by the SA node. The PQ-wave represents atrial contraction.

(b) The QR-wave is preceded by ventricular contraction. It represents the spread of the impulse of contraction from the AV node to the wall of the ventricle. It leads to ventricular depolarisation.

(c) The RS-wave represents ventricular contraction of about 0.3 sec.

(d) The ST-wave represents ventricular relaxation of about 0.4 sec. During this phase, the ventricles relax and return to their normal state.

(e) The T-wave represents ventricular relaxation.


SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='2' AND subId='7' AND ex_no!=0 AND status=1 and id!=353 ORDER BY views desc, last_viewed_on desc limit 0,10
SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='2' AND subId='7' AND ex_no!=0 AND status=1 and id!=353 ORDER BY last_viewed_on desc limit 0,10

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  • 4 months ago

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  • Answered by Ekta Mehta
  • 4 months ago

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  • Answered by Ekta Mehta
  • 4 months ago

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