The Circulatory System (CIE AS Biology)

Fig. 1 represents a capillary as it passes through the tissues of the body along with the surrounding tissue fluid.

Fig. 1

Give three differences between the composition of the blood at the arteriole end of the capillary and the venule end.

Use Fig. 1 to explain the formation of tissue fluid and its return to the capillary.

Protein deficiency in an individual's diet can influence the return of tissue fluid to the capillaries.

Suggest and explain one tissue fluid-related symptom of dietary protein deficiency.

The main component of both blood and tissue fluid is water.

Explain how one property of water makes it an ideal transport medium for organisms with a transport system.

Elevated tissue fluid pressure is a characteristic of body tissues containing cancerous tumour cells.

This is, in part, due to the high permeability of blood vessels, low lymphatic drainage, hypertension (high blood pressure) and high cell density around the blood vessels.

Figure 1 shows the change in tissue fluid pressure (mmHg) within tumour tissue and healthy tissue. 

Fig. 1

Calculate the percentage change in tissue fluid pressure between the tumour tissue and healthy tissue.

Use the information provided in part (a) and your own knowledge of tissue fluid formation to explain the results of the graph of the tumour tissue. 

Explain the mechanisms that maintain normal tissue fluid pressure in healthy tissue.

Tissue fluid makes up around 19% of our body mass. 

Calculate the mass of tissue fluid in a person with a total body mass of 72kg. Give your answer in grams to 3 significant figures.

Arterioles are blood vessels that help control blood flow into a capillary. 

Explain how. 

Fig. 1 shows the blood pressure through different blood vessels of the human circulatory system. 

Fig. 1

Use the data shown in Fig. 1 to explain why arterioles play a large role in regulating blood pressure. 

The mean arterial pressure (MAP) is used to determine overall blood flow and is a good indicator of perfusion pressure (how much pressure it takes to push blood through all the blood vessels in a specific area). In a healthy individual MAP is 70-100 mmHg.

MAP can be calculated by the following formula:

MAP= DP + 1/3(SP − DP)

Where

• DP is diastolic pressure
• SP is systolic pressure

Fig. 2 shows pulse pressure (mmHg) within different blood vessels.

Fig. 2

Use the graph to calculate the mean arterial pressure and determine whether it is within a healthy range. Give your answer to 2 significant figures. 

Figure 1 shows an image of a micrograph of a cross-section through a mammalian blood vessel.

Fig. 1

Identify the type of blood vessel shown in Figure 1.

Explain how the blood vessel shown in Figure1 is adapted to carry out its function.

Figure 2 shows pressure changes in the blood vessels as the blood passes through different sections of the mammalian circulatory system.

Fig. 2

Explain the need for a separate systemic and pulmonary circulation in mammals. 

Explain the blood pressure in the following sections of Fig. 2

[3]

[1]

[1]

Based on your knowledge of diffusion, explain why multicellular organisms need a specialised transport system.

Figure 1 shows an organ of the mammalian circulatory system.

Image courtesy of Wiki Commons copyright free

Fig. 1

Identify the organ in Fig. 1. 

[1]

Explain the evidence shown in Fig. 1 that determined your answer to part (i).

[2]

Figure 2 shows a biological drawing of Organ A

Fig. 2

Describe the errors contained within this drawing.

The heart, contains two blood vessels that transport blood via the lungs. 

Give the name of these two blood vessels. 

[1]

Explain the movement of blood between the heart and the lungs. Do not include details of the cardiac cycle as part of your answer.

[4]

Tissue fluid bathes almost all cells outside of the circulatory system.

Describe the formation of tissue fluid. 

The table below shows the differences between blood plasma and tissue fluid. 

Explain the differences shown in the table.

Table 1

Water is a major component of tissue fluid. 

Explain the properties of water that enable its role of transport in mammals.

Lymphoedema is a condition that causes swelling in the legs or arms due to a build up of tissue fluid. 

With reference to pressure, explain why someone with lymphoedema would have swelling in their arms or legs. 

Blood is comprised of different cells. Figure 1 shows an electron micrograph of a blood sample. 

Identify on the diagram the three types of blood cells shown. 

Fig. 1

Blood is found within blood vessels.

Compare the structure of a vein with the structure of an elastic artery. 

Capillaries are the site of diffusion of substances required by cells, such as glucose and oxygen. 

Explain how the structure of capillaries relates to their function. 

Complete the table to show the properties of the blood vessels.