2. Think about…
3.1 Importance of regulating gas content in blood
3.2 Control of breathing
3.3 Control of heartbeat
3.4 Effects of exercise on breathing and cardiac output
Recall ‘Think about…’
Summary concept map

3. CPR - a skill for life
cardiopulmonary resuscitation (心肺復蘇法)

4. CPR - a skill for life
The survival chance is higher if patients are treated by CPR within 6 minutes after breathing and heartbeat have stopped.

5. CPR - a skill for life
CPR involves blowing exhaled air forcefully into the lungs and compressing the chest.

6. CPR - a skill for life
They are done alternately in rhythm until breathing and pulse resume.

7. 1 Why does blowing exhaled air into the
lungs of the patient help sustain life

8. 2
What is the purpose of compressing
the chest

9. Which gas content in blood must be kept stable?
3.1 Importance of regulating gas content in blood
Which gas content in blood must be kept stable?

10. carbon dioxide content
3.1
Importance of regulating gas content in blood
oxygen content
carbon dioxide content
for respiration

11. carbon dioxide content
3.1
Importance of regulating gas content in blood
oxygen content
carbon dioxide content
affects blood pH
affects functioning of enzymes

12. carbon dioxide content
3.1
Importance of regulating gas content in blood
oxygen content
carbon dioxide content
depend on
how fast the gases are exchanged in the air sacs
how fast blood is transported from the heart to the lungs and body cells

13. carbon dioxide content
3.1
Importance of regulating gas content in blood
oxygen content
carbon dioxide content
regulated by
controlling breathing and heartbeat

14. 1 Importance of regulating the gas content in blood:
3.1
Importance of regulating gas content in blood
1 Importance of regulating the gas content in blood:
a To ensure there is a sufficient supply of oxygen to body cells for
respiration

15. 1 Importance of regulating the gas content in blood:
3.1
Importance of regulating gas content in blood
1 Importance of regulating the gas content in blood:
b To maintain a stable blood pH for in cells to function properly.
enzymes

16. 2 By controlling and breathing , the body can regulate heartbeat
3.1
Importance of regulating gas content in blood
2 By controlling and
breathing
heartbeat
, the body can regulate
The gas content in blood.

17. under the involuntary control by the medulla oblongata
3.2 Control of breathing
under the involuntary control by the medulla oblongata
front
back

18. detect changes in carbon dioxide content and oxygen content in blood
3.2
Control of breathing
Which part of the medulla oblongata controls breathing?
respiratory centre
contains chemoreceptors
detect changes in carbon dioxide content and oxygen content in blood

19. stretch receptors in lungs
3.2
Control of breathing
chemoreceptors in:
carotid bodies
aortic bodies
respiratory centre
nerve impulses
stretch receptors in lungs

20. nerve impulses to respiratory muscles to trigger inhalation
3.2
Control of breathing
chemoreceptors in:
carotid bodies
aortic bodies
respiratory centre
nerve impulses to respiratory muscles to trigger inhalation
stretch receptors in lungs

21. stimulated when the lungs inflate
3.2
Control of breathing
respiratory centre
stimulated when the lungs inflate
Inhibitory nerve impulses
stretch receptors in lungs

22. when there is no impulse, exhalation occurs
3.2
Control of breathing
chemoreceptors in:
carotid bodies
aortic bodies
respiratory centre
when there is no impulse, exhalation occurs
stretch receptors in lungs

23. stretch receptors in lungs
3.2
Control of breathing
chemoreceptors in:
carotid bodies
aortic bodies
respiratory centre
nerve impulses
stretch receptors in lungs

24. How does the respiratory centre control breathing?
3.2
Control of breathing
How does the respiratory centre control breathing?
the basic rhythm is brought about by feedback mechanisms between the respiratory centre and stretch receptors

25. stretch receptors stimulated neurones inhibited
3.2
Control of breathing
stretch receptors stimulated
neurones inhibited
respiratory centre
inhalation
exhalation
stretch receptors no longer stimulated
neurones stimulated

26. one breath = inhalation + exhalation
3.2
Control of breathing
one breath = inhalation + exhalation
rate of breathing (呼吸速率) = number of breaths per minute
 measures how fast we breathe
depth of breathing (呼吸深度) = volume of air that we breathe in
after an exhalation
 measures how deeply we breathe

27. Effects of CO2 content in blood on breathing
3.2
Control of breathing
Effects of CO2 content in blood on breathing
respiratory centre responds to changes in blood pH
in blood:
in body cells (high CO2 conc)
CO2
H2O H+
HCO3-
in air sacs (low CO2 conc)
lowers blood pH

28. normal CO2 content in blood
3.2
Control of breathing
respiratory centre (contains chemoreceptors)
chemoreceptors in aortic and carotid bodies
faster and stronger contraction of intercostal muscles and diaphragm muscles
CO2 content in blood rises (blood pH falls)
rate and depth of breathing increase
CO2 content falls
normal CO2 content in blood

29. normal CO2 content in blood
3.2
Control of breathing
normal CO2 content in blood
CO2 content rises
CO2 content in blood falls (blood pH rises)
rate and depth of breathing decrease
slower and weaker contraction of intercostal muscles and diaphragm muscles
chemoreceptors in aortic and carotid bodies
respiratory centre (contains chemoreceptors)

30. 1 The feedback mechanisms between the and the
3.2
Control of breathing
1 The feedback mechanisms between the and the
respiratory centre
stretch receptors
in the lungs
bring about the basic rhythm of breathing.

31. 3.2
Control of breathing
2 When carbon dioxide content in blood rises, blood pH This is detected by the in the respiratory centre, the aortic and carotid bodies.
falls
chemoreceptors

32. 3.2
Control of breathing 2
The receptors send to the respiratory centre. The centre causes the muscles and
nerve impulses
intercostal
muscles to contract
diaphragm
faster and more strongly. This increases the rate and depth of breathing. The opposite occurs when carbon dioxide content in blood falls.

33. a group of special cardiac muscles
3.3 Control of heartbeat
Which part of our body initiates heartbeat?
Animation
sinoatrial (SA) node (竇房結)
a group of special cardiac muscles

34. generates electrical impulses
3.3 Control of heartbeat
Which part of our body initiates heartbeat?
sinoatrial (SA) node (竇房結)
generates electrical impulses

35. also called the pacemaker
3.3 Control of heartbeat
Which part of our body initiates heartbeat?
sinoatrial (SA) node (竇房結)
also called the pacemaker

36. aorta pulmonary artery anterior vena cava pulmonary veins left artrium
3.3
Control of heartbeat
aorta
pulmonary artery
anterior vena cava
pulmonary veins
left artrium
right atrium
left ventricle
right ventricle
posterior vena cava

37. both atria contract at the same time
3.3
Control of heartbeat
both atria contract at the same time
pacemaker

38. the ventricles contract after contraction of the atria
3.3
Control of heartbeat
the ventricles contract after contraction of the atria
atrio-ventricular (AV) node

39. the sequence of events that take place in one heartbeat
3.3
Control of heartbeat
What happens in a cardiac cycle?
Animation
the sequence of events that take place in one heartbeat

40. 1 Atria contract (atrial systole)
3.3
Control of heartbeat
1 Atria contract (atrial systole)
electrical impulses spread from the pacemaker to the atria
the atria contract
atria
0.1s
0.4s
0.8s
relaxation / diastole
ventricles
contraction / systole

41. 1 Atria contract (atrial systole)
3.3
Control of heartbeat
1 Atria contract (atrial systole)
the ventricles are in a relaxed state
the semilunar valves are closed
atria
0.1s
0.4s
0.8s
relaxation / diastole
ventricles
contraction / systole

42. 2 Ventricles contract (ventricular systole) the atria relax
3.3
Control of heartbeat
2 Ventricles contract (ventricular systole)
the atria relax
electrical impulses reach the ventricles and cause them to contract
this occurs about 0.1 s after the atria started contracting
atria
0.1s
0.4s
0.8s
relaxation / diastole
ventricles
contraction / systole

43. 2 Ventricles contract (ventricular systole)
3.3
Control of heartbeat
2 Ventricles contract (ventricular systole)
time is allowed for the ventricles to fill completely with blood before they contract
the pressure inside the ventricles increases as they contract, the semilunar valves are forced to open
atria
0.1s
0.4s
0.8s
relaxation / diastole
ventricles
contraction / systole

44. 2 Ventricles contract (ventricular systole)
3.3
Control of heartbeat
2 Ventricles contract (ventricular systole)
the tricuspid and bicuspid valves are forced to close
 the first heart sound ‘lub’
atria
0.1s
0.4s
0.8s
relaxation / diastole
ventricles
contraction / systole

45. 3 Atria and ventricles relax (diastole)
3.3
Control of heartbeat
3 Atria and ventricles relax (diastole)
both the atria and the ventricles are in a relaxed state
the semilunar valves are closed
 the second heart sound ‘dub’
atria
0.1s
0.4s
0.8s
relaxation / diastole
ventricles
contraction / systole

46. 3 Atria and ventricles relax (diastole)
3.3
Control of heartbeat
3 Atria and ventricles relax (diastole)
blood from the venae cavae and the pulmonary veins flows into the atria and the cycle repeats
atria
0.1s
0.4s
0.8s
relaxation / diastole
ventricles
contraction / systole

47. When a person is at rest, the heart rate is about 60 to 80 beats/min.
3.3
Control of heartbeat
What is cardiac output?
heart rate (心搏率) = number of heartbeats per minute
When a person is at rest, the heart rate is about 60 to 80 beats/min.

48. When a person is at rest, the stroke volume is about 70 mL.
3.3
Control of heartbeat
What is cardiac output?
stroke volume (心搏量) = volume of blood pumped by each
ventricle in one heartbeat
When a person is at rest, the stroke volume is about 70 mL.

49. 3.3
Control of heartbeat
What is cardiac output?
cardiac output (心輸出量) = volume of blood pumped by each
ventricle per minute
cardiac output (mL/min)
stroke volume (mL/beat)
heart rate (beats/min) x =
 measures the performance of the heart as a pump

50. How does the body control cardiac output?
3.3
Control of heartbeat
How does the body control cardiac output?
Nervous control
Hormonal control

51. 1 Nervous control medulla oblongata cardiovascular centre (心血管中樞)
3.3
Control of heartbeat
1 Nervous control
medulla oblongata
cardiovascular centre
(心血管中樞)
consists of
cardio-acceleratory centre
cardio-inhibitory centre

52. cardio-acceleratory centre cardio-inhibitory centre
3.3
Control of heartbeat
1 Nervous control
pacemaker
stimulated to increase cardiac output
sympathetic nerve (交感神經)
cardio-acceleratory centre
cardio-inhibitory centre

53. cardio-acceleratory centre cardio-inhibitory centre
3.3
Control of heartbeat
1 Nervous control
pacemaker
parasympathetic nerve (副交感神經)
cardio-acceleratory centre
cardio-inhibitory centre

54. cardio-acceleratory centre cardio-inhibitory centre
3.3
Control of heartbeat
1 Nervous control
pacemaker
inhibited to decrease cardiac output
vagus nerve (迷走神經)
cardio-acceleratory centre
cardio-inhibitory centre

55. detect changes in carbon dioxide content and oxygen content in blood
3.3
Control of heartbeat
chemoreceptors in:
carotid bodies
aortic bodies
cardio-vascular centre

56. detect changes in blood pressure
3.3
Control of heartbeat
sensory nerve
detect changes in blood pressure
chemoreceptors in:
carotid bodies
aortic bodies
stretch receptors in:
carotid arteries
aorta
cardio-vascular centre

57. stimulated when blood pressure increases
3.3
Control of heartbeat
sensory nerve
stimulated when blood pressure increases
chemoreceptors in:
carotid bodies
aortic bodies
stretch receptors in:
carotid arteries
aorta
cardio-vascular centre

58. cardio-vascular centre pacemaker vagus nerve
3.3
Control of heartbeat
sensory nerve
chemoreceptors in:
carotid bodies
sensory nerve
aortic bodies
stretch receptors in:
carotid arteries
aorta
sympathetic nerve
cardio-vascular centre
pacemaker
vagus nerve

59. cardio-inhibitory centre in medulla oblongata
3.3
Control of heartbeat
vagus nerve
cardio-inhibitory centre in medulla oblongata
chemoreceptors in aortic and carotid bodies
stretch receptors in aorta and carotid arteries
blood pH rises
blood pressure rises
normal blood pH / blood pressure

60. pacemaker is inhibited
vagus nerve
3.3
Control of heartbeat
pacemaker is inhibited
slower and weaker contraction of cardiac muscles
cardiac output decreases
blood flow to lungs decreases
blood pH falls; blood pressure falls

61. cardio-inhibitory centre in medulla oblongata
3.3
Control of heartbeat
vagus nerve
cardio-inhibitory centre in medulla oblongata
chemoreceptors in aortic and carotid bodies
stretch receptors in aorta and carotid arteries
blood pH rises
blood pressure rises
normal blood pH / blood pressure

62. normal blood pH / blood pressure
3.3
Control of heartbeat
normal blood pH / blood pressure
blood pH falls
blood pressure falls
chemoreceptors in aortic and carotid bodies
stretch receptors in aorta and carotid arteries
cardio-acceleratory centre in medulla oblongata
sympathetic nerve

63. blood pH rises; blood pressure rises
3.3
Control of heartbeat
blood pH rises; blood pressure rises
cardiac output increases
blood flow to lungs increases
pacemaker is stimulated
faster and stronger contraction of cardiac muscles
sympathetic nerve

64. normal blood pH / blood pressure
3.3
Control of heartbeat
normal blood pH / blood pressure
blood pH falls
blood pressure falls
chemoreceptors in aortic and carotid bodies
stretch receptors in aorta and carotid arteries
cardio-acceleratory centre in medulla oblongata
sympathetic nerve

65. 3.3
Control of heartbeat
2 Hormonal control
 When a person is under stress or excited, adrenal gland secretes more adrenaline (腎上腺素).
adrenal gland
kidney

66. 3.3
Control of heartbeat
2 Hormonal control
 When a person is under stress or excited, adrenal gland secretes more adrenaline (腎上腺素).

67. 3.3
Control of heartbeat
2 Hormonal control
 Adrenaline is transported around the body by the circulation of blood.
blood vessel

68. 3.3
Control of heartbeat
2 Hormonal control
 Adrenaline is transported around the body by the circulation of blood.

69. 3.3
Control of heartbeat
2 Hormonal control
 Adrenaline acts on cardiac muscles to increase the cardiac output.

70. 3.3
Control of heartbeat
2 Hormonal control
the cardiac output increases to prepare the body for action in emergencies

71. 1 How the pacemaker initiates a heartbeat:
3.3
Control of heartbeat
1 How the pacemaker initiates a heartbeat:
a The pacemaker generates
electrical impulses
that cause
both atria to contract at the same time.

72. atrioventricular node
3.3
Control of heartbeat
1 How the pacemaker initiates a heartbeat:
b The impulses also travel to the
atrioventricular node
. The AV
node relays the impulses to the base of the
ventricles

73. 1 How the pacemaker initiates a heartbeat:
3.3
Control of heartbeat
1 How the pacemaker initiates a heartbeat: b
The ventricles contract about 0.1s
after
the atria started contracting.

74. 2 In a cardiac cycle: Time interval 0-0.1 s Atria Ventricles
3.3
Control of heartbeat
2 In a cardiac cycle:
Time interval
0-0.1 s
Atria
Ventricles
Blood flow
Atria to ventricles
Contract
Relax

75. 2 In a cardiac cycle: Time interval 0-0.1 s
3.3
Control of heartbeat
2 In a cardiac cycle:
Time interval
0-0.1 s
Tricuspid and bicuspid valves
Semilunar valves
Open
Close

76. 2 In a cardiac cycle: Time interval 0.1-0.4 s Atria Ventricles
3.3
Control of heartbeat
2 In a cardiac cycle:
Time interval s
Atria
Ventricles
Blood flow
Right ventricle to pulmonary artery
Left ventricle to aorta
Relax
Contract

77. 2 In a cardiac cycle: Time interval 0.1-0.4 s
3.3
Control of heartbeat
2 In a cardiac cycle:
Time interval s
Tricuspid and bicuspid valves
Semilunar valves
Close (gives 1st heart sound)
Open

78. 2 In a cardiac cycle: Time interval 0.4-0.8 s Atria Ventricles
3.3
Control of heartbeat
2 In a cardiac cycle:
Time interval s
Atria
Ventricles
Blood flow
Venae cavae to right atrium
Pulmonary veins to left atrium
Relax
Relax

79. 2 In a cardiac cycle: Time interval 0.4-0.8 s
3.3
Control of heartbeat
2 In a cardiac cycle:
Time interval s
Tricuspid and bicuspid valves
Semilunar valves
Close
Close (gives 2nd heart sound)

80. a is the number of heartbeats per minute.
3.3
Control of heartbeat 3
a is the number of heartbeats per minute.
Heart rate
b is the volume of blood pumped by each ventricle in one heartbeat.
Stroke volume

81. c is the volume of blood pumped by each ventricle per minute.
3.3
Control of heartbeat 3
c is the volume of blood pumped by each ventricle per minute.
Cardiac output
cardiac output (mL/min)
stroke volume (mL/beat)
heart rate (beats/min) x =

82. cardiovascular centre
3.3
Control of heartbeat
4 Control of cardiac output:
a When the CO2 content in blood rises or blood pressure falls, the
cardiovascular centre
sends
more nerve impulses along the
sympathetic
nerve to the
pacemaker to increase the cardiac output.

83. 4 Control of cardiac output:
3.3
Control of heartbeat
4 Control of cardiac output:
b When the CO2 content in blood falls or blood pressure rises, the cardiovascular centre sends more
nerve impulses along the
vagus
nerve to the pacemaker
to the cardiac output.
decrease

84. 4 Control of cardiac output:
3.3
Control of heartbeat
4 Control of cardiac output:
c When a person is under stress or excited, the adrenal glands secrete more to increase the cardiac output.
adrenaline

85. How does exercise affect the rate and depth of breathing?
3.4 Effects of exercise on breathing and cardiac output
How does exercise affect the rate and depth of breathing?

86.  more oxygen is needed to allow a higher rate of aerobic respiration
3.4
Effects of exercise on breathing and cardiac output
during exercise, the energy requirement for vigorous muscular activity increases
 more oxygen is needed to allow a higher rate of aerobic respiration
 achieved by increasing both the rate and depth of breathing

87. volume of air in lungs (cm3)
3.4
Effects of exercise on breathing and cardiac output
4000
during exercise
3000
volume of air in lungs (cm3)
2000
at rest
1000 5 10 15 20
time (s)

88. as we breathe faster and deeper, gas exchange occurs at a higher rate
3.4
Effects of exercise on breathing and cardiac output
as we breathe faster and deeper, gas exchange occurs at a higher rate
blood flow O2
CO2

89. as we breathe faster and deeper, gas exchange occurs at a higher rate
3.4
Effects of exercise on breathing and cardiac output
as we breathe faster and deeper, gas exchange occurs at a higher rate
 body can supply oxygen to muscle cells and remove carbon dioxide from them more rapidly

90.  provides more oxygen for the breakdown of lactic acid
3.4
Effects of exercise on breathing and cardiac output
after exercise, the rate and depth of breathing remain at a high level for some time
 provides more oxygen for the breakdown of lactic acid

91. 3.4
Effects of exercise on breathing and cardiac output
the amount of oxygen required to remove all lactic acid after exercise is called oxygen debt (氧債)
amount of O2 breathed in
time
rest
exercise
recovery
rest

92. 3.4
Effects of exercise on breathing and cardiac output
the rate of breathing can be measured by counting the number of breaths within a certain period of time
the depth of breathing can be measured by a breath volume kit, a data logger with a respiration rate sensor or a spirometer (肺量計)

93. 1 Sit down quietly for 2 minutes.
3.4
Effects of exercise on breathing and cardiac output
3.1
Video
Study of the changes in breathing before and after exercise using a breath volume kit
1 Sit down quietly for 2 minutes.
2 Get a classmate ready to do the timing and counting. Breathe through the mouthpiece of the breath volume kit for 20 seconds.

94. 3 Record the number of breaths you take in that 20 seconds.
3.4
Effects of exercise on breathing and cardiac output
3.1
3 Record the number of breaths you take in that 20 seconds.
4 Force all of the air in the bag to the far end and record its volume.
5 Run on the spot for 3 minutes.
6 Repeat steps 2 to 4 to record the number of breaths and the volume of exhaled air in 20 seconds.

95. 2 Connect the low pressure sensor to the interface.
3.4
Effects of exercise on breathing and cardiac output
3.2
Video
Study of the changes in breathing before and after exercise using a data logger
Part 1: Computer set-up
1 Connect the data logger interface to the computer. Turn on the interface and the computer.
2 Connect the low pressure sensor to the interface.

96. 3 Run the software and open the pre-configured file.
3.4
Effects of exercise on breathing and cardiac output
3.2
3 Run the software and open the pre-configured file.
Part 2: Equipment set-up
1 Wrap around the chest of the test classmate with the respiration belt.
2 Connect the tube of the rubber bladder to the low pressure sensor.

97. 1 Let the test classmate sit down quietly for 2 minutes.
3.4
Effects of exercise on breathing and cardiac output
3.2
3 Close the valve of the squeeze bulb. Squeeze the bulb to inflate the rubber bladder.
Part 3: Data recording
1 Let the test classmate sit down quietly for 2 minutes.
2 Start recording his / her breathing rate before exercise (i.e. at rest).
3 Record data for 1 minute and then stop.

98. 5 Record data for 1 minute and then stop.
3.4
Effects of exercise on breathing and cardiac output
3.2
4 Let the test classmate run on the spot and start recording his / her breathing rate during exercise at the same time.
5 Record data for 1 minute and then stop.
6 Ask the test classmate to stop running and sit down. At the same time, start recording his / her breathing rate after exercise for 1 minute again.

99. 1 Use the graph display function to display the data.
3.4
Effects of exercise on breathing and cardiac output
3.2
Part 4: Data analysis
1 Use the graph display function to display the data.
2 Calculate the minimum, maximum and mean breathing rate for each run by using the built-in functions of the software.

100. How does exercise affect cardiac output?
3.4
Effects of exercise on breathing and cardiac output
How does exercise affect cardiac output?

101. during exercise, the cardiac output increases
3.4
Effects of exercise on breathing and cardiac output
during exercise, the cardiac output increases
 facilitates the transport of oxygen to muscle cells and carbon dioxide to the lungs for removal

102. cardiovascular centre stimulated
3.4
Effects of exercise on breathing and cardiac output
exercise
cardiovascular centre stimulated
pacemaker generates more electrical impulses
adrenal glands secrete more adrenaline
cardiac muscles contract faster and more strongly
cardiac output increases

103. the heart rate can be measured by
3.4
Effects of exercise on breathing and cardiac output
the heart rate can be measured by
- a data logger with a heart rate sensor
- measuring the pulse with a pulse sensor

104. 2 Connect the heart rate sensor to the interface.
3.4
Effects of exercise on breathing and cardiac output
3.3
Video
Study of the changes in heart rate before and after exercise using a data logger
Part 1: Computer set-up
1 Connect the data logger interface to the computer. Turn on the interface and the computer.
2 Connect the heart rate sensor to the interface.

105. 3 Run the software and open the pre-configured file.
3.4
Effects of exercise on breathing and cardiac output
3.3
3 Run the software and open the pre-configured file.
Part 2: Equipment set-up
1 Clip the ear clip of the heart rate sensor to the earlobe of the test classmate.
2 Connect the ear clip to the heart rate sensor.

106. 1 Let the test classmate sit down quietly for 2 minutes.
3.4
Effects of exercise on breathing and cardiac output
3.3
Part 3: Data recording
1 Let the test classmate sit down quietly for 2 minutes.
2 Start recording his / her heart rate before exercise (i.e. at rest).
3 Record data for 1 minute and then stop.

107. 5 Record data for 1 minute and then stop.
3.4
Effects of exercise on breathing and cardiac output
3.3
4 Let the test classmate run on the spot and start recording his / her heart rate during exercise at the same time.
5 Record data for 1 minute and then stop.
6 Ask the test classmate to stop running and sit down. At the same time, start recording his / her heart rate after exercise for 1 minute again.

108. 1 Use the graph display function to display the data.
3.4
Effects of exercise on breathing and cardiac output
3.3
Part 4: Data analysis
1 Use the graph display function to display the data.
2 Calculate the minimum, maximum and mean heart rate for each run by using the built-in functions of the software.

109. a During exercise, both the rate and depth of breathing .
3.4
Effects of exercise on breathing and cardiac output 1
a During exercise, both the rate and depth of breathing
increase

110. b This allows the body to obtain
3.4
Effects of exercise on breathing and cardiac output 1
b This allows the body to obtain
oxygen
for aerobic respiration
in muscle cells and remove
carbon dioxide
from them at a
higher rate. They also provide oxygen to break down
lactic acid
produced during anaerobic respiration in the muscle cells.

111. cardiovascular centre
3.4
Effects of exercise on breathing and cardiac output
exercise 2
cardiovascular centre
stimulated
adrenal glands secrete
more
adrenaline
pacemaker
generates
more electrical impulses
cardiac muscles contract faster and more strongly
cardiac output increases

112. 3.4
Effects of exercise on breathing and cardiac output 3
The increased cardiac output facilitates the transport of oxygen to muscle cells for respiration and the transport of carbon dioxide to the for removal.
aerobic
lungs

113. 1 Why does blowing exhaled air into
the lungs of the patient help sustain life?
Exhaled air still contains 16% oxygen which helps maintain oxygenation of the blood.

114. 1 Why does blowing exhaled air into
the lungs of the patient help sustain life?
Its high carbon dioxide content also helps stimulate the respiratory centre to trigger breathing in the patient.

115. 2 What is the purpose of compressing the chest?
Compressing the chest helps maintain cardiac output to supply blood to the brain and other vital organs. This delays damage to tissues until further medical treatment is available.

116. carbon dioxide content (blood pH)
Gas content in blood
refers to
carbon dioxide content (blood pH)
oxygen content
regulated by controlling
breathing
heartbeat

117. cardiovascular centre
breathing
heartbeat
controlled by
controlled by
once in one
respiratory centre
cardiovascular centre
cardiac cycle
stretch receptors
receive nerve impulses from
chemoreceptors
and

118. intercostal muscles and diaphragm muscles rate and depth of breathing
respiratory centre
sends nerve impulses to
intercostal muscles and diaphragm muscles
to regulate
rate and depth of breathing

119. rate and depth of breathing
cardiac output
increase during
exercise

120. cardiovascular centre
sends nerve impulses along
sympathetic nerve
vagus nerve
pacemaker
adrenal glands
secrete adrenaline to increase
determines
cardiac output