2.2 Organisation: The Cardiovascular & Respiratory System

Which statement is true of the pulmonary circuit of the circulatory system?

Describe the differences between arteries and veins.

Mammals and birds have a double circulatory system.

Explain why a double circulatory system is better suited to these organisms, compared to a single circulatory system.

Describe the the path of blood from the vena cava to the lungs and from the lungs to the aorta. You don't need to reference alveoli in your answer. 

Describe how heart rate is controlled and explain why some people may need to have an artificial pacemaker fitted.

Explain how red blood cells are adapted for their function.

Patient A visited a doctor with a sore throat and muscle aches. The doctor ordered a blood test.

Table 1 shows some of the results from Patient A's blood sample. 

Table 1

Suggest what conclusions can be drawn from the blood test results in Table 1.

A scientist conducts an experiment to investigate how exercise affects the the flow of blood (each test lasted for five minutes).

Firstly, they measured the volume of blood that passes through a blood vessel of a seated subject.

Secondly, they measured the volume of blood that passes through a blood vessel when the subject was walking on a treadmill.

Some selected data is shown in Table 2.

Table 2

Calculate the missing values and explain why there is a difference in results between the two tests

Explain how the structure of a capillary is adapted to carry out its function.

Figure 1 shows a diagram of an alveolus in close proximity to a capillary.

Alveoli are relatively spherical in shape. The alveolus shown in Figure 1 has a diameter of 400 μm and a volume of approximately 33 504 000 μm³.

Calculate the surface to volume ratio of the alveolus in Figure 1.

Use the equation:

Explain why heart and breathing rates increase in response to aerobic exercise.

Explain how the human circulatory system is adapted to carry out its function of supplying oxygen to the body and removing waste products.

A patient is diagnosed as having suffered from a stroke due to a blood clot as a result of an irregular heartbeat.

A stroke is a life-threatening illness in which cells of the brain die due to lack of oxygen.

Suggest how a blood clot could cause a stroke.

Explain how a patient with an irregular heartbeat would be treated.

Describe with reasons the differences in wall thickness of the atria and ventricles.

In your answer compare the right and left ventricles.

One form of cholesterol found in the blood is LDL.

Describe how having too high a level of LDL cholesterol in the blood could potentially lead to a heart attack.

Listing the key structures, describe the path of air from the trachea to the lung capillaries.

Explain the changes that occur in the thorax (chest cavity) when a person breathes in.

During inhalation and exhalation, the intercostal muscles work as antagonistic pairs.

With reference to the intercostal muscles, explain what antagonistic pairs are and how they work.

The internal intercostal muscles are predominantly active during strenuous activity.

Why is this?

Figure 1 below shows a cross-section of a blood vessel taken from an arm.

Figure 1

Name the type of blood vessel in Figure 1 and describe the key evidence that supports your answer.

Using the letters S and T describe the usual direction of blood flow in the vessel shown in Figure 1.

Suggest a reason why blood usually flows in the same direction in the vessel shown in Figure 1 and describe why this is an advantageous adaptation.

The carotid arteries are major blood vessels in the neck that supply oxygenated blood to the brain, neck and face.

The blood flow of the left carotid artery of a patient during a 5 minute period was measured at 1.1 litres.

Calculate the rate of blood flow and the total volume of blood that passes through this vessel in one hour.