What percentage of ventricular filling is achieved by atrial contraction?

1. 30

2. 50

3. 70

4. 90

The right atria of the human heart receive:
1. Oxygenated blood
2. Deoxygenated blood
3. Arterial blood
4. Venous blood

The hepatic portal vein drains blood to liver from 

Blood pressure in the pulmonary artery is

(1) more than that in the carotid

(2) more than that in the pulmonary vein

(3) less than that in the venae cavae

(4) same as that in the aorta

Arteries are best defined as the vessels which