Biology : Body Fluids and Circulations

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

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

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

• 0.5 sec

• 0.8 sec

• 1 sec

• 1.5 sec

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

In which form CO₂ is mostly carried by blood

•  bicarbonate

• carbonic acid

• Carbamino compound

• Carboxyhaemoglobin