Adrenalin

Figure 9 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 10 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.

_........ beats per minute

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

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

Respiration occurs in cells.

Why do cells respire?

An athlete runs every day as part of their training.

Explain why the breathing rate of the athlete increases when running.

When the athlete is running, their muscle cells use both aerobic respiration and anaerobic respiration.

State two differences between aerobic respiration and anaerobic respiration.

Bromothymol blue (BTB) solution is an indicator of pH.

Figure 2 shows the colour of BTB at different pH levels.

When air is passed through green BTB, for one minute, the solution stays green.

When a person breathes out through a straw into BTB for one minute the solution turns yellow.

Explain why the air breathed out turns the BTB solution yellow.

A scientist placed pondweed into two sealed test tubes containing green BTB solution.

Test tube A was kept in the dark. Test tube B was kept in the light. All other conditions were kept the same. Figure 3 shows these test tubes at the start of the investigation.

Figure 4 shows the colour of the BTB solution after 5 hours.

Explain the results for tube A and tube B shown in Figure 4.

Figure 3 shows a cross-section of an artery and a vein.

(Source: © The University of Kansas Medical Center)

Figure 3

Explain one difference between the artery wall and the vein wall shown in Figure 3.

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

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.

Calculate the volume of blood travelling to the muscles during exercise.

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

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 7.

This measurement was used to calculate the heart rate.

The athlete exercised for 20 minutes.

The heart rate was recorded every 5 minutes during each type of exercise.

State how the heart rate was calculated using this method.

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

Figure 8 shows the results of this investigation.

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

Exercise increases adrenalin levels.

State which endocrine gland secretes adrenalin.

Explain the effect of adrenalin on liver cells during exercise.

After high intensity exercise, the pH of muscles can decrease from pH 7.0 to pH 6.3.

Explain this change in pH.

Exercise causes changes in the circulation of the blood.

In an investigation, the change in blood flow to different parts of the body during exercise was measured.

All the volunteers used in the study were healthy females of the same age.

Figure 9 shows the results of this investigation.

During exercise, the blood flow to the stomach changes.

Calculate the percentage change in blood flow to the stomach in response to exercise.

Give your answer to the nearest whole number

_........ %

Suggest two other variables that should be controlled in this investigation.

*(iii) Explain the changes in blood flow, shown in Figure 9, that are caused by exercise.

Figure 8 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 10 shows the concentration of the hormones oestrogen and progesterone in the blood of women of different ages.

Use information from Figure 10 to explain why women over the age of 50 are less likely to ovulate.

Use information from Figure 10 to explain why women are less likely to menstruate after the age of 60.

Explain how clomifene therapy may increase the chance of a woman over the age of 50 becoming pregnant.

The hormone progesterone is produced by the

Explain how the release of adrenalin can result in the improved performance of an athlete.