Gas exchange

Figure 7 shows the structure of the human heart and the direction of blood flow.

Measure the thickness of the left ventricle wall between points T and U.

Describe how deoxygenated blood leaves the right side of the heart and becomes oxygenated.

Which blood vessel returns deoxygenated blood to the right side of the heart?

Figure 7 shows the valves that stop blood from flowing in the wrong direction.

State the number of valves in the right side of the human heart shown in Figure 7.

The heart is part of the circulatory system.

Describe what happens to the blood when the left ventricle contracts.

Figure 8 shows information about three types of blood vessel.

State the type of blood vessel shown as C in Figure 8.

Describe how the structure of a capillary helps gas exchange in the lungs.

In humans, gas exchange occurs in the alveoli of the lungs.

Figure 6 shows the structure of an alveolus and its blood supply.

Which process moves carbon dioxide from the blood into the alveolus?

State one adaptation of an alveolus that increases the rate of gas exchange.

Describe how blood is moved from the heart to the lungs.

Figure 7 shows the heart rate of a person before, during and after exercise.

Describe the trend shown in Figure 7.

Use data from Figure 7 to support your answer.

Explain the trend shown in Figure 7 from 5 minutes to 25 minutes.

The stroke volume is the volume of blood pumped during one beat of the heart.

At 25 minutes the stroke volume was 0.13 dm³.

Calculate the cardiac output of the heart of this person at 25 minutes.

Use the equation

cardiac output = stroke volumeheart rate

_........ dm³ per minute

Gas exchange happens in the alveoli in the lungs.

Figure 7 shows an alveolus and a capillary.

(adapted from: sciencepics/shutterstock)

Figure 7

Name the gas used in respiration that moves from the alveolus into the capillary.

Name the gas produced by respiration that moves from the capillary into the alveolus.

The capillary wall is only one cell thick.

Explain how gases move from the alveolus to the capillary.

Explain the advantages of red blood cells passing one at a time through this narrow capillary.

The average number of alveoli in each human lung is 280 million.

The surface area of 1 million alveoli is 0.25 m².

Calculate the total surface area of a human lung.

Figure 11 shows ciliated epithelial cells from the airways of a human as seen using a light microscope.

Draw the cell labelled A in the box below.

Label three parts of this cell on your diagram.

State the function of the ciliated epithelial cells in the airways of the human breathing system.

Figure 12 shows equipment used to investigate the rate of respiration in maggots.

As the maggots respire, the drop of coloured liquid moves towards the test tube.

Figure 13 shows the position of the drop of coloured liquid after ten minutes.

Use information from Figures 12 and 13 to calculate the mean rate of respiration of the maggots in mm per minute.

_........ mm per minute

*(c) Explain how alveoli in human lungs are adapted for gas exchange.

Include the names of the gases that are being exchanged.

Figure 2 shows alveoli from a healthy lung.

Smoking can cause a condition called emphysema.

Figure 3 shows alveoli from a person with emphysema.

Use words from the box to complete the following sentences.

breathing diffusion larger

osmosis smaller thicker

The alveoli from the person with emphysema have a_........

surface area than the alveoli from a healthy lung.

The surface area of the alveoli will affect how much oxygen moves into the blood

by the process of_........ .

The graph in Figure 4 shows the volume of oxygen an athlete absorbs at different running speeds.

Describe the trend shown in Figure 4.

Which uses more oxygen when the running speed of the athlete changes from 4 to 6 km per hour?

Explain why the athlete produces lactic acid when running at 14 km per hour.