Which of the following is a correct statement:

1. The volume of blood in pulmonary circulation is more than the volume of blood in systemic circulation at any instant

2. The blood pressure in pulmonary circulation is less than that of the systemic circulation

3. Double circulation is characteristic of all vertebrates

4. A double aortic arch is seen in birds and mammals

Doctors use a stethoscope to hear the sounds produced during each cardiac cycle. The

second sound is heard when

1. AV valves open up

2. Ventricular walls vibrate due to gushing in of blood from atria

3. Semilunar valves close down after the blood flows into vessels from ventricles

4. AV node receives the signal from SA node

Blood pressure in the mammalian aorta is maximum during

1. systole of the left atrium

2. diastole of the right ventricle

3. systole ot the left ventricle

4. diastole of the right atrium

The duration of cardiac cycle is–

(1) 0.8 second

(2) 0.5 second

(3) 0.3 second

(4) 0.4 second

If the stroke volume of Human heart is considered 80 mL and to pump 5L of blood how many beats are required?

(1) 63

(2) 70

(3) 72

(4) 60