Q 01/05

The circulatory system is divided into which two major circuits?

A) Arterial and venous

B) Pulmonary and systemic

C) Cardiac and lymphatic

D) Coronary and cerebral

Answer · why

B) Pulmonary and systemic

The pulmonary loop carries blood from the right heart to the lungs and back to the left heart; the systemic loop serves everything else.

Q 02/05

What is the largest artery in the human body?

A) The carotid

B) The aorta

C) The femoral

D) The pulmonary artery

Answer · why

B) The aorta

It leaves the left ventricle, makes a hairpin turn called the arch and ends in the abdomen by splitting into the two common iliac arteries.

Q 03/05

Which two large veins return deoxygenated blood from the body to the right atrium?

A) The internal jugular and femoral veins

B) The superior and inferior vena cava

C) The right and left pulmonary veins

D) The hepatic and renal veins

Answer · why

B) The superior and inferior vena cava

From the right atrium the blood is pumped into the pulmonary circuit to pick up oxygen.

Q 04/05

Arteries branch into which small passages before reaching the capillaries?

A) Venules

B) Arterioles

C) Sinusoids

D) Lymphatics

Answer · why

B) Arterioles

On the way back, capillaries merge into venules, which merge into veins.

Q 05/05

Roughly what is the diameter of a capillary?

A) 20 to 40 micrometres

B) 5 to 10 micrometres

C) 50 to 100 micrometres

D) About 1 millimetre

Answer · why

B) 5 to 10 micrometres

Their walls are a single layer of squamous endothelial cells, thin enough for gas and nutrient exchange.