Circulation, Breathing, Health and Disease

Which chamber of the heart has the thickest muscle wall?

• Left atrium

• Left ventricle

• Right atrium

• Right ventricle

What is the function of a red blood cell?

• blood clotting

• defending against disease

• transporting hormones

• transporting oxygen

What is the most likely cause of a heart attack?

• blocked coronary arteries

• diet lacking in vitamins C and D

• infection by microorganisms

• regular exercise

Which blood vessel has a high carbon dioxide concentration, a low oxygen concentration and a high blood pressure?

• aorta

• pulmonary artery

• pulmonary vein

• vena cava

The diagrams show four different stages in one heart beat. What is the correct order for the stages after stage P?

• Q > R > S

• R > Q > S

• R > S > Q

• S > R > Q

Which substance is transported by haemoglobin?

• nitrogen

• oxygen

• urea

• water

What is the characteristic feature of a double circulation?

• In each circuit, blood passes from the gut to the liver before going back to the heart.

• In each circuit, blood passes from the heart to the lungs and then back to the heart before going to other parts of the body.

• In each circuit, blood passes through atria and ventricles before going to other parts of the body.

• In each circuit, blood passes through the arteries and the capillaries before returning to the heart in veins.

What helps oxygen to be absorbed rapidly into the blood in the lungs?

• Air breathed in has less oxygen than air breathed out.

• Alveoli have thick walls and a large surface area.

• Alveoli have thin walls and a large surface area.

• The concentration of oxygen in the blood is higher than in the alveoli.

A girl holds her breath for 30 seconds, breathes out, and then breathes in. Compared with the air she breathes out, the air she breathes in contains less:

• carbon dioxide and water vapour.

• nitrogen and water vapour.

• oxygen and carbon dioxide.

• oxygen and nitrogen.

The diagram shows a section through an alveolus and a capillary. Why does carbon dioxide move from X to Y?

• Air has a lower concentration of carbon dioxide than blood.

• Carbon dioxide moves more freely in air than in blood.

• Carbon dioxide must replace oxygen.

• Diffusion of carbon dioxide can only be out of the blood.