Biology Unit Test - Grade 8

Which blood vessel returns blood from the lungs to the heart?

• aorta

• pulmonary artery

• pulmonary vein

• renal vein

Which events occur during ventricular systole?

• Atrioventricular valves close.

• Muscle in ventricle walls relaxes.

• Semilunar valves open.

The diagram shows a section through the heart. What is the function of the structure labelled Q?

• It controls the amount of blood leaving the heart.

• It increases the pressure in part R.

• It prevents backflow of blood into part P.

• It prevents blood flowing into the vena cava.

Which statement correctly links muscular or elastic arteries to their function?

• The aorta is an example of a muscular artery as it transports blood from the left ventricle of the heart.

• Elastic arteries expand when the heart contracts and then recoil as the heart relaxes to maintain pressure.

• Arteries further away from the heart are muscular arteries as they transport blood at high pressure.

• Muscular arteries facilitate smoother blood flow than elastic arteries as their walls expand and recoil.

The photomicrograph shows a section through a structure found in mammals viewed using a light microscope. What are the main components of layer W?

• smooth muscle and elastic fibres

• elastic fibres and collagen fibres

• collagen fibres only

• squamous epithelial cells forming an endothelium

What occurs during ventricular systole in a mammalian heart?

• Aortic pressure increases.

• Atrial pressure does not change.

• Ventricular pressure increases.

What ensures one-way flow of blood in the circulatory system?

• valves

• ventricles

• septum

• atria

The diagrams show sections through three blood vessels, which are not drawn to the same scale. In which order will red blood cells flow through these vessels when travelling from the right ventricle to the left atrium of the heart?

• 1 →2→3

• 1 →3→2

• 2 →3→1

• 3 →1→2

Which tissue types are present in the walls of all blood vessels?

• collagen

• elastic

• endothelial

• smooth muscle

The statements list some of the events in the cardiac cycle. They are not in the correct order. Which statement describes the sixth of these events to occur in the cardiac cycle?

• 1

• 3

• 4

• 5