Multiple Choice Questions

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If heart beats 75 beats/min. then what is time for cardiac cycle ?

  • 0.5 sec

  • 0.8 sec

  • 1 sec

  • 1.5 sec


B.

0.8 sec

In human beings, the cardiac cycle takes about 0.8 second.

The time for auricular systole is 0.1 second and that for auricular diastole is 0.7 second. Ventricular systole, which consists of the compression period (0.1 sec) and the expression period (0.2 second) takes 0.3 second and ventricular diastole takes 0.5 second. Hence, the total systole occupies 0.4 second and joint diastole 0.4 second.

Therefore, if heart beats 75 beats/min, then the time for one complete cardiac cycle is 0.8 sec.


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Which one of the following is a matching pair?

  • Lubb - sharp closure of AV valves at the beginning of ventricular systole

  • Dup - sudden opening of semilunar valves at the beginning of ventricular diastole

  • Pulsation of the radial artery - valves in the blood vessels

  • Initiation of the heart beat - Purkinje fibres


Assertion : Smaller the organism higher is the rate of metabolism per gram weight.

Reason : The heart rate of a six month old baby is much higher than that of an old person.

  • If both Assertion and Reason are true and the reason is the correct explanation of the assertion

  • If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

  • If Assertion is true statement but Reason is false

  • If both Assertion and Reason are false statements


Which proteolytic enzyme induces lysis of fibrin during fibrinolysis ?

  • Fibrin

  • Thrombin

  • Plasmin

  • Platelet factor-VII


Rate of heart beat is determined by :

  • AV-node

  • SA-node

  • Purkinje fibres

  • Papillary muscles


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The first heart sound is produced when :

  • diastole begins

  • semilunar valve close quickly

  • interventricular pressure decreases

  • bicuspid and tricuspid valve close quickly


Which of the following layer of heart wall consists of cardiac muscles ?

  • Endocardium

  • Myocardium

  • Epicardium

  • All of these


Blood pressure increases and heart rate decreases in response to :

  • exercise

  • haemorrhage

  • exposure to high altitude

  • increased intracranial pressure


'P' wave of ECG occurs before the:

  • onset of ventricular ejection

  • end of atrial contraction

  • begining of atrial contraction

  • none of the above


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In which form CO2 is mostly carried by blood

  •  bicarbonate

  • carbonic acid

  • Carbamino compound

  • Carboxyhaemoglobin


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