Introduction to the circulatory system

What is the function of the circulatory system?

• Carry chemicals to all points in the body

• Carry waste products away from the cells

• Carry dissolved gases to the cells

• All of the other answers are right

Answer explanation

The circulatory system is a highway for blood around the body. Within the blood are chemicals that need to be taken to the body cells, and waste products being carried away from them.

What are the three main types of blood vessel called?

• Arteries, veins and hearts

• Arteries, capillaries and blood

• Arteries, veins and capillaries

• Venules, arterioles and capillaries

Answer explanation

The main types of blood vessel are called arteries, veins and capillaries. Arterioles and venules are smaller blood vessels that connect the arteries and veins to the capillaries.

What is the function of arteries?

• To carry blood away from the heart, towards the body tissues

• To carry blood away from the tissues, towards the heart

• To pump blood around the body

• To allow gas exchange

Answer explanation

Arteries always carry blood away from the heart. They have a thick vessel wall that are elastic and can stretch to cope with the high pressure of the blood within.

What is the function of a vein?

• To carry blood away from the heart, towards the body tissues

• To carry blood towards the heart, away from the body tissues

• To pump blood around the body

• To allow gas exchange

Answer explanation

Veins always carry blood towards the heart, away from the body tissues. They have thin walls and a large lumen, carrying low pressure blood. Because of that low pressure, they also have valves to prevent the blood flowing backwards.

What is the function of a capillary?

• To carry blood away from the heart, towards the body tissues

• To carry blood towards the heart, away from the body tissues

• To pump blood around the body

• To allow gas exchange

Answer explanation

Capillaries are incredibly thin vessels that run through the body tissues. They slow the blood down so that there is time for materials (including gases) to be exchanged with the body cells to keep them alive.

The circulatory system consists of 2 separate circuits that work together. What are they?

• Pulmonary and respiratory

• Systemic and respiratory

• Pulmonary and systemic

• Skeletal and excretory

Answer explanation

The pulmonary circulation takes blood from the heart to the lungs, and back.

The systemic circulation takes blood from the heart to the rest of the body systems, and back.

What is the aorta?

• An artery

• A vein

• Part of the heart

• A capillary

Answer explanation

The aorta is the largest artery in the body, carrying the highest pressure blood out of the heart at the beginning of the systemic circulation.

What is the name of the blood vessel that returns blood from the lungs to the heart?

• Aorta

• Vena cava

• Pulmonary artery

• Pulmonary vein

Answer explanation

The pulmonary vein carries blood towards the heart from the lungs.

What is the proper name for a red blood cell?

• Leukocyte

• Erythrocyte

• Platelet

• Fibrinogen

Answer explanation

Red blood cells are really called erythrocyte, which comes from Greek words meaning red (erythro-) and cell (-cyte).

What is the role of leukocytes?

• Blood clotting

• Transport of oxygen

• Defence and immunity

• Transport of carbon dioxide

Answer explanation

Leukocytes are part of the immune system that use the bloodstream to travel around the body.