The heart and circulation

Figure 12 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 12 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 12.

The heart is part of the circulatory system.

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

Figure 13 shows information about three types of blood vessel.

State the type of blood vessel shown as C in Figure 13.

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

Figure 14 is a diagram of the human heart.

Which chambers of the heart contain only oxygenated blood?

The heart has a valve called the bicuspid valve between chamber Q and chamber R.

Explain the role of this valve.

Explain why heart rate increases during exercise.

Every person has a maximum heart rate.

Figure 15 shows how different types of activity affect a person’s heart rate and the type of respiration they are using during that activity.

A person had a maximum heart rate of 190 beats per minute. Calculate the heart rate of this person when they are jogging.

Give your answer to 3 significant figures.

Erythrocytes (red blood cells) transport oxygen to respiring cells.

Explain how erythrocytes (red blood cells) are adapted to carry and release oxygen.

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

Figure 9 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 10 shows the heart rate of a person before, during and after exercise.

Describe the trend shown in Figure 10.

Use data from Figure 10 to support your answer.

Explain the trend shown in Figure 10 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

The heart pumps blood.

Explain why the wall of the left ventricle of the heart is thicker than the wall of the right ventricle of the heart.

A centrifuge can be used to separate the different parts of human blood.

Figure 12 shows blood separated into different parts.

Name part X.

Which substance, needed for cellular respiration, is carried by red blood cells?

Name two types of white blood cell.

When a person donates blood, 470 cm³ of blood is removed from their body.

Red blood cells make up 44% by volume of the blood.

Calculate the volume of red blood cells in 470 cm³ of donated blood.

Give your answer to the nearest whole number.

Before donating blood, a person has a small blood sample taken to check that the blood is healthy.

State two precautions a doctor should take when collecting this sample.

8 (a) Figure 9 shows a human heart.

(i) Draw arrows on Figure 9 to show the direction of blood flow through the left side of the heart.

(ii) Name the main blood vessel that carries deoxygenated blood into the heart.

(b) Figure 10 shows the heart rate and stroke volume of a person when at rest and when doing exercise.

Figure 10

(i) Calculate the difference in cardiac output when at rest and when doing exercise. Give your answer to 3 significant figures and include units in your answer.

(ii) Explain why the cardiac output needs to increase during exercise.

3 Figure 5 shows a diagram of the human blood system.

(a) (i) Name blood vessel X.

(ii) Which row of the table shows the width of the wall and blood pressure in blood vessel X?

(b) Figure 6 shows the pressure of blood flowing through the arteries, capillaries and veins of a person.

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 time in seconds

Figure 6

Calculate the difference in blood pressure from the maximum in the arteries to the minimum in the veins.

(c) Figure 7 shows a diagram of a vein with blood cells.

(i) Identify structure Q.

(ii) State the function of structure Q.

(d) Describe how the heart causes blood to move to the lungs.

9 (a) Figure 17 shows a cross-section of an artery and a vein.

(Source: © The University of Kansas Medical Center)

Figure 17

(i) Explain one difference between the artery wall and the vein wall shown in Figure 17.

(ii) Name one structure that is found in veins but not found in arteries.

(b) A human body has 5 dm³ of blood. At rest 20% of the blood travels to the muscles. During exercise 60% of the blood travels to the muscles.

(i) Calculate the volume of blood travelling to the muscles during exercise.

(ii) Explain one reason why there is an increase in blood flow to muscles during exercise.

*(c) Figure 18 shows the structure of the human heart.

Figure 18

Explain how the structure of the heart is related to its function.

8 The effect of different types of exercise on the heart rate of an athlete was investigated. The athlete counted the number of beats in 10 seconds at the carotid artery pulse point, as shown in Figure 12. This measurement was used to calculate the heart rate.

(Source: © dityazemli/Shutterstock)

Figure 12

The athlete exercised for 20 minutes. The heart rate was recorded every 5 minutes during each type of exercise.

(a) (i) State how the heart rate was calculated using this method.

(ii) Give two ways of improving the method used to obtain the data needed to calculate the heart rate.

Figure 13 shows the results of this investigation.

Figure 13

(iii) Comment on the difference in the heart rates during these types of exercise.

(b) Exercise increases adrenalin levels.

(i) State which endocrine gland secretes adrenalin.

(ii) Explain the effect of adrenalin on liver cells during exercise.

(c) After high intensity exercise, the pH of muscles can decrease from pH 7.0 to pH 6.3. Explain this change in pH.

Figure 1 shows a diagram of the heart.

Figure 1

Draw arrows on Figure 1 to show how oxygenated blood moves through the heart.

What happens when the right ventricle contracts?

Draw one straight line from each structure to its function.

Figure 2 shows a dissected vein.

Explain how the valves in veins help the blood, at low pressure, flow towards the heart.

The equipment used to dissect the vein was cleaned and put into disinfectant.

State why this equipment was put into disinfectant.

Figure 13 shows the heart rate of person A and person B.

Person A does not do any regular exercise.

Person B has been running regularly for one year.

Both people rested for the first 6 minutes, then did the same high intensity exercise for the next 12 minutes, then rested.

Compare the heart rates of person A with the heart rates of person B.

The stroke volume for person B before exercising was 61 ml per beat.

Calculate the cardiac output for person B before exercising.

Give your answer in litres per minute.

_........ litres per minute

The cardiac output for person A during exercise was 5.5 litres per minute.

Explain why the heart rate for person A needed to be higher than the heart rate for person B during exercise.

(a) Figure 6 shows a cross section of an artery and a vein.

(Source: © The University of Kansas Medical Center)

Figure 6

Measure the length of line A and the length of line B in mm.

State the ratio of the thickness of the artery wall to the thickness of the vein wall.

Give a reason why veins have valves.

Name the artery that transports oxygenated blood from the heart to the body.

A scientist investigated the relationship between exercise and the ability to run at 3 metres per second for 20 minutes.

The scientist collected data from six groups of people. Each group exercised for a different number of hours per week for six months.

There were 100 people in each group.

Figure 7 shows their results.

Describe the relationship shown by this data.

Explain why some people’s leg muscles tired quickly and developed cramp when they were running.

(a) Figure 9 shows the stroke volume at different heart rates of a person who has trained for a marathon and of a person who has not trained for a marathon.

Compare the effect of heart rate on stroke volume of the person who has trained for a marathon with the person who has not trained for a marathon.

Calculate the cardiac output for the person who has trained for a marathon when the heart rate is 160 beats per minute. Give the units in your answer.

*(b) Blood from the body enters the heart through the vena cava.

Describe how this blood flows through the heart and lungs to leave the heart through the aorta.

Include references to the chambers of the heart and the relevant valves in your answer.

(a) Figure 19 shows a diagram of a red blood cell from a turtle and a diagram of a red blood cell from a human.

These cells are animal cells.

Animal cells do not have

The actual length of the red blood cell from a turtle is 20.5 μ m.

Calculate the length of the magnified image of the red blood cell of the turtle when magnified 400 ×.

The width of the human red blood cell, when magnified 400 ×, is 3.08 mm.

Calculate the actual width of the cell and show your answer in standard form.

Red blood cells are carried in veins and arteries.

Figure 20 shows the equipment used to measure the elasticity of an artery.

Describe a method you could use to see how much the ring of tissue from an artery could stretch before it no longer returned to its original size.

Give one safety precaution you need to take when handling animal tissue such as blood vessels.

Figure 21 shows the circulatory system of a frog.

Explain why the circulatory system of a frog is less efficient at carrying oxygen to the tissues than the circulatory system of a human.

Figure 10 shows the estimated blood flow through some parts of the body when a person is at rest and during exercise.

Compare the rate of blood flow through the body when this person is at rest and during exercise.

Explain why there is a change in the rate of blood flow through the digestive system during exercise.

The stroke volume is the amount of blood leaving one chamber of the heart per beat.

From which chamber of the heart does this volume of oxygenated blood flow?

A person has a cardiac output of 4.9 litres per minute. The stroke volume of each heart beat is 70 ml.

Calculate the heart rate.