1.

The diagram below shows an electrocardiogram (ECG) recorded from a healthy person. The P and R waves are labelled.

R

P

1 second

(a)

Explain why there is a brief delay between the P wave and the R wave. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................(2)

(b)

From the ECG, calculate the heart rate in beats per minute. Show your working.

Answer ....................................................(3) (Total 5 marks)

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2.

The diagram below shows part of a section at low magnification through the root of a dicotyledonous plant.

(a)

Name the parts labelled A, B, C and D. A ............................................................................................................................... B ............................................................................................................................... C ............................................................................................................................... D ...............................................................................................................................(2)

(b)

Describe how water passes from part A to part D. . . . . . . . .(4)

(c)

A root takes up mineral ions in addition to water. An investigation was carried out into the effects of aeration on the uptake of nitrate ions (NO 3 ) by plant roots. Sections of root, including the root hairs, were immersed in a culture solution containing 6.3 mmol per dM3 of nitrate ions. The solution was aerated (air was bubbled through it). After nine hours the root sections were removed and the concentration of nitrate ions in the root cells was determined.

The procedure was repeated with a second batch of root sections from which the root hairs had been removed. Both procedures were then repeated without aeration. The results are shown in the table below.

C o n c e n tr a tio n o f n itr a te io n s / m m o l d m R o o t s e c tio n W ith a e r a tio n W ith o u t a e r a tio n W ith ro o t h a ir s 3 7 .5 7 .1

3

W ith o u t ro o t h a ir s 6 .2 6 .3

(i)

Suggest an explanation for the difference between the results with and without aeration when the root hairs were present. ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................(4)

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(ii)

Suggest reasons for the results obtained when no root hairs were present. ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................(2) (Total 12 marks)

3.

(a) Cardiac muscle contracts myogenically. Explain what is meant by the term myogenic. . . . .(2)

(b)

The diagram below shows structures in the heart which are concerned with the coordination of contraction.

(i)

Name parts A, B and C. A B C (3)

(ii)

Explain how the structures shown in the diagram coordinate the contraction of the heart. (3) (Total 8 marks)

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4.

Graph 1 below shows the pressure changes that occur in the left side of the mammalian heart during one complete cardiac cycle. Graph 2 shows the ECG trace for the same cycle.15 A 1 P r e s s u 5 0 r e / k P a L e f t v e n t r i c l e o r t a G ra p h 1

L e ft a triu m

0

R P E l e c t r o c a r d i o g Q 0 .0 0 .1 r a m S

T

G

r a p

h

2

0 .2

0 .3

0 .4 T i m

0 .5 e /

0 .6 s

0 .7

0 .8

(a)

Name the stage of the cardiac cycle that is represented by the QRS wave on the ECG in Graph 2. .....................................................................................................................................(1)

(b)

With reference to Graph 1, describe the pressure changes in the left ventricle during its contraction. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(2)

(c)

Identify the following features on Graph 1 above, and label them with the appropriate letters. X = the point at which the bicuspid (atrioventricular) valve first closes Y = the point at which the semilunar (aortic) valve first closes(2)

(d)

Use the information in Graph 1 to calculate the heart rate. Show your working.

Answer ........................................................(2)

(e)

(i) On the grid below sketch an ECG pattern that you would expect to see for a person with tachycardia (an abnormally fast rhythm).

E

l e c t r o

c a r d

i o

g

r a m

0 .0

0 .1

0 .2

0 .3

0 .4 T i m

0 .5 e /

0 .6 s

0 .7

0 .8 (2)

(ii)

Suggest why this person is not necessarily suffering from heart disease. ........................................................................................................................... ...........................................................................................................................(1)

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(iii)

Suggest two tests, other than measuring heart rate, that could be carried out to help determine if this person is likely to be suffering from heart disease. 1 ........................................................................................................................ 2 ........................................................................................................................(2) (Total 12 marks)

5.

The data below show some of the changes that occur in the cardiovascular system as a result of different levels of exercise. Level of exercise At rest Heart rate 1 /beats min Cardiac output 3 1 /dm min 72 5 Light 144 13 Medium 160 16 Intense 190 21

(a)

Using the data from the table, calculate the stroke volume when exercising at an intense level. Show your working.

Answer .........................................(2)

(b)

The graph below shows typical blood pressures at different levels of exercise. 2 0 0 r e 0 / m m H g

B

l o

o

d

p

r e s s u 1 5

1

0

0 S p y s t o l i c r e s s u r e

5

0

D i a s t o l i c p r e s s u r e

0

A

t

r e s Lt i g h M t L e v e l

e d i Iu n m t e n s e o f e x e r c i s e

(i)

Explain what is meant by the term blood pressure. (1)

(ii)

With reference to the graph, describe the effect of exercise on blood pressure. (3)

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(iii)

Using the data in the table and the graph, suggest why the systolic pressure rises with increasing level of exercise. (2)

(c)

State two sites in the body where blood pressure receptors are found. 1 ......................................................................................................................................... 2 .........................................................................................................................................(2) (Total 10 marks)

6.

The table below shows the blood flow to cardiac muscle and to the skin at different levels of exercise. Blood flow/cm per minute Level of exercise Rest Low intensity Medium intensity High intensity Cardiac muscle 250 350 650 1800 Skin 500 1500 1800 10003

(a)

(i) Calculate the percentage increase in the rate of blood flow to cardiac muscle as the level of exercise increases from resting to a medium level of intensity. Show your working.

Answer ..................................(2)

(ii)

Explain why cardiac muscle requires a greater rate of blood flow as the intensity of exercise increases. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................(2)

(b)

An increase in blood flow to the skin allows more heat to be lost through radiation and sweating. This helps to prevent the body temperature from rising above normal during exercise. (i) Compare the changes in blood flow to cardiac muscle and to the skin, as exercise increases from low intensity to high intensity. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................(2)

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(ii)

Suggest explanations for the changes in blood flow to the skin as exercise increases from low intensity to high intensity. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................(3) (Total 9 marks)

7.

The diagram below shows the pathways for the conduction of electrical impulses during the cardiac cycle.

X

P a t h w a y s c o n d u c t i o e l e c t r i c a l

f o

r

t h

e l s e s

n o f i m p u

(a)

Name the structure labelled X. .....................................................................................................................................(1)

(b)

Describe how the structures shown in the diagram control the complete cardiac cycle. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(4) (Total 5 marks)

8.

The diagram below illustrates some aspects of the regulation of heart rate.

(a)

Complete the flow diagram by naming the part of the heart that receives impulses from the two nerves(1)

13

(b)

Strenuous physical activity will increase the volume of blood flowing through the venae cavae and into the right atrium. This will trigger a reflex action. (i) Name the reflex that will be initiated. ...............................................................................................................................(1)

(ii)

Using your own knowledge and the information provided, explain how this increase in blood volume in the venae cavae and right atrium causes a change in heart rate. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................(3)

(c)

The coordination of the heart beat is disrupted when the conducting systems of the heart are damaged. This type of disease is called heart block. Describe how an artificial pacemaker can be used to treat this condition. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... .......................................................................................................................................(3) (Total 8 marks)

9.

The graphs below show some of the pressure and volume changes that take place in the left side of the heart during part of a cardiac cycle. 1 1 V o l u m3 3 2 0 0 K L e y e f t v e n t r i c l e

1 1 0 e / c m 1 0 0 9 8 7 0 A 1 1 6 4 P a B 0 0 0 T i m e

K A L

e y o r t a e f t v e n t r i c l e

P

r e s s u

1 2 r e / k 1 0 8 6 4 2 0 A

T B

i m

e

(a)

Using information from the graphs above, describe and explain the events which produce the change in the volume of blood in the left ventricle between the times A and B. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(4)

(b)

During a cardiac cycle, a wave of electrical activity spreads over the atria and ventricles.15

(i)

Name the group of cells that initiates the wave of electrical activity that controls the cardiac cycle. ...........................................................................................................................(1)

(ii)

State where in the heart this group of cells is located. ...........................................................................................................................(1)

(iii)

Describe and explain how the electrical activity of the heart ensures that the ventricles begin contracting from the apex (base) of the heart. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................(3) (Total 9 marks)

10.

As part of a study of the effects of exercise on the heart, the heart rates of four men were measured. The results are shown in the table below. Heart rate immediately after 1 exercise / beats min 80 115 127 102

Resting heart rate / 1 beats min Gary Neil Adnan James 65 74 76 70

Percentage increase in heart rate 23.1 55.4

(a)

(i) Complete the table by calculating the percentage increase in the heart rates for Adnan and James.(1)

(ii)

Calculate the mean percentage increase in the heart rate for these four men.

Answer .................................%(1)

(iii)

Give two factors you would expect to have been controlled in this investigation to produce meaningful results. ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................(2)

(b)

Gary is the only man who exercises regularly. Suggest why Garys resting heart rate and percentage increase in heart rate are the lowest. Give a reason for your answer. ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(2) (Total 6 marks)

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11.

Exercise affects pulse rate and blood pressure. (a) Explain what is meant by the term pulse. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(2)

(b)

The graph below shows typical blood pressures at different levels of exercise. 2 0 r e

B l o o d p r e s s u / k P a 1 5

1

0

S p

y s t o l i c r e s s u r e

D i a s t o l i c p r e s s u r e

5

0

A

t

r e sLt i g L e v

h Mt e l o

e d f

i u I nm t e n e x

s e

e r c i s e

(i)

Using the data in the graph, calculate the increase in systolic blood pressure from rest to a light level of exercise. Show your working.

Answer (2)

(ii)

Suggest why the systolic pressure increases with exercise. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................(2)

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(iii)

Using the information in the graph, compare the effects of exercise on the systolic and diastolic blood pressures. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................(3) (Total 9 marks)

12.

An electrocardiogram (ECG) is a recording of the electrical activity of the heart during the cardiac cycle. (a) Explain what is meant by the term cardiac cycle. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(3)

(b)

The recording below shows an ECG from a healthy person.

(i)

On the ECG, label an R wave.(1)

(ii)

The time interval between the start of the P wave and the start of the R wave indicates the time taken for the impulse to travel along the bundle of His. This time interval varies from about 0.13 to 0.16 seconds. Explain why it is important that there is a short delay between the P and R waves. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................(3) (Total 7 marks)

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13.

Read through the passage below on the heart, and then write on the dotted lines the most appropriate word or words to complete the passage. Contraction of the atria (atrial systole) is stimulated by an impulse generated by the ................................................., situated in the wall of the right atrium. The impulse reaches the walls of the ................................................. by means of the bundle of His and Purkyne (Purkinje) fibres. Oxygenated blood is supplied to the heart muscle by the ................................................. which branch directly from the aorta. Heart muscle contains a dense network of ................................................., from which oxygen diffuses to the muscle.(Total 4 marks)

14.

The recording below is an electrocardiogram (ECG) from a healthy person.

(i)

On the ECG, label a T wave.(1)

(ii)

This ECG was recorded over a period of 5 seconds. Count the number of complete cardiac cycles, and then calculate the heart rate, in beats per minute. Show your working. Number of complete cardiac cycles = ........................................

Heart rate = ........................................ beats per minute.(3) (Total 4 marks)

15.

(a) The diagram below shows the structure of a heart and associated blood vessels from a mammal. Name the parts labelled A, B and C. A ................................................................... B ................................................................... C ...................................................................(3)

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(b)

Explain what is meant by the term cardiac cycle. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(3)

(c)

Heart muscle is described as myogenic. Explain what is meant by the term myogenic. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...........................................................................................................................................(2) (Total 8 marks)

16.

(a)

Name the region of the human brain involved in control of heart rate.(1)

.....................................................................................................................................

(b)

Heart rate increases during exercise. Explain the mechanisms involved in controlling this increase in heart rate. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(4) (Total 5 marks)

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17.

This question is about changes in the physiology of whales, penguins, seals and humans when they hold their breath to dive below the surface of water. (a) Figures 1 and 2, below, show the changes in blood lactate concentration during diving in white whales and emperor penguins. Figure 1. Blood lactate concentration in the blood of white whales (Delphinapterus leucas) before and after diving.

B lo o d la c ta te c o n c e n tra tio n / m m o l d m

3

t = 3P