6.2 The Blood System

The following diagram compares the structure of two main blood vessels in the body.

Identify blood vessel A.

[1 mark]

State a reason for your answer in part i).

[1 mark]

Blood vessel B has a very large lumen.

Identify blood vessel B.

[1 mark]

State one reason for the presence of a large lumen in blood vessel B.

[1 mark]

The flow of blood in veins is not assisted by the pressure generated by the beating of the heart.

List two structures that assist with the flow of blood in veins.

[2 marks]

Systolic pressure is one of the measurements taken by a doctor to determine the blood pressure of a patient.

Define the term 'systolic pressure'.

[1 mark]

The following diagram shows part of the blood circulation of a mammal.

Identify one example of an artery in this diagram. 

[1 mark]

Based on the information in the diagram, state a reason for your answer in part i).

[1 mark]

Mammals have two separate circulations that supply blood to different organs.

State the name of the circulation that blood vessels T and S form part of.

[1 mark]

The following table shows the mean pressure (in mmHg) measured in different blood vessels of the body.

Calculate the percentage difference between the mean blood pressure of the aorta and vena cava. Show your working and give your answer to three significant figures.

[2 marks]

Using the table provided, identify the blood vessels where the greatest decrease in mean blood pressure occurs.

[1 mark]

The following diagram compares the structure of an artery of a healthy person with that of someone suffering from atherosclerosis.

Identify structure X.

[1 mark]

Atherosclerosis can lead to the occlusion of arteries over time.

Define the term 'occlusion'.

[1 mark]

Occlusion of the arteries can have a serious impact on cardiovascular health.

List two consequences of an occlusion of the arteries.

[2 marks]

When blood flow to part of the heart muscle is restricted it will impair its ability to contract fully. This will reduce blood flow, and therefore oxygen flow, to the body tissues.

State one way in which the heart will compensate for this.

[1 mark]

One mark is available for clarity of communication throughout this question.

Atherosclerosis results in a build-up of fatty deposits known as plaque inside arteries, which may lead to coronary heart disease.

Outline the risk factors for developing atherosclerosis.

[5 marks]

Capillaries provide the exchange surface in the tissues of the body.

List three characteristics of capillaries.

[3 marks]

Describe the flow of oxygenated blood through the left side of the heart as it returns from the lungs.

[6 marks]