The Circulatory System and Gas Exchange Review
1. Define the following:
Erythrocyte
Red blood cell, transports oxygen.
Leukocyte
--Lymphocyte
--Phagocyte
Platelets
Plasma
Myogenic
Artery
Vein
Capillary
Pulmonary
2. The blood carries heat. List six further materials carried in the blood.
 Water,
3. a. State the name and function of the blood vessels labeled in this image:
Blood vessels:

Function:

b. Further learning: outline the cause and effects of a myocardial infarction.

4. Label the vessels, chambers and valves in the heart:
Blood vessels
a.
b.
c.
d.
Chambers of the heart
e.
f.
g.
h.
Valves
i.
j.
k.
l.
5. Explain the action of the heart.
 Blood flows in to the atria from veins.




6. State the role of valves in the circulatory system.

7. Describe why the flow of blood is considered a double circulation.
8. Explain how exercise leads to an increase in heart rate.
9. Explain the relationship between the structure and function of these blood vessels.
Artery
Vein
Capillary
10. Marine mammals have a series of physiological responses to diving. This enables them to stay submerged for
long periods in water colder than their body temperature. Collectively these responses are termed the diving
reflex.
To investigate the diving reflex in humans, heart rate changes in ten healthy subjects were monitored during
facial immersions in water ranging from 3 °C to 37 °C. The data for this experiment is shown below.
–5
–10
–15
Percentage change in heart rate
–20
–25
–30
–35
0
5
10
15
20
25
30
Water temperature / ºC
35
40
[Source: N R York, Effect of Water Temperature on Diving Reflex Induced Bradycardia in Humans,
http://kesler.biology.rhodes.edu/sciJ/York.html]
(a)
(i)
State the effect of facial immersion on heart rate over the range of temperatures shown on the
graph.
o
(1)
(ii)
Suggest one reason for the relationship between facial immersion and heart rate.
o
(1)
(b)
Outline the effect of the water temperature on heart rate.
o
(1)
(c)
Calculate the heart rate of a person immersed in water at a temperature of 15°, if their heart rate before
immersion was 70 beats per minute.
(2)
(Total 5 marks)
Question from QuestionBank CDROm
11. Define the following:
Ventilation
Movement of air into and out of the lungs.
Gas exchange
Cell respiration
Deoxygenated
Oxygenated
12. Explain the need for ventilation in humans.
Size
Oxygen
Carbon dioxide
Concentration gradient
Humans are large, land-based organisms that cannot exchange gas sufficiently with the
air through diffusion alone. A central ventilation system allows gases to be exchanged
with the blood and carried around the body to the cells that require it.
13. Deduce the number of membranes an oxygen molecule must pass through in order to enter an erythrocyte.
14. Label the features of the alveoli and describe how they are adapted for their function.
a.
b.
Many invaginations and millions of alveoli – large surface area
c.
Moist membranes.
d.
Membranes only one cell thick.
15. Label this diagram of the human ventilation system.
a. Trachea
b.
c.
d.
e.
Also don’t forget to be able to draw and label a magnified alveolus.
Explain the method of ventilation of the lungs.
Feature
Inhalation
External intercostal
muscles
Contract, pulling ribcage
up and out.
Exhalation
Internal intercostal
muscles
Diaphragm
Abdominal muscles
Lung volume
Pressure in lungs
Decreases, sucking air
into the lungs.
Data-based question practice, from the IB Biology QuestionBank CDRom.
16. A major requirement of the body is to eliminate carbon dioxide (CO2). In the body, carbon dioxide exists in
three forms: dissolved CO2, bound as the bicarbonate ion, and bound to proteins (e.g. haemoglobin in red
blood cells or plasma proteins). The relative contribution of each of these forms to overall CO2 transport
varies considerably depending on activity, as shown in the table below.
CO2 Transport in Blood Plasma at Rest and During Exercise
Rest
Exercise
Arterial
Venous
Venous
mmol I–1 blood
mmol I–1 blood
mmol I–1 blood
dissolved CO2
0.68
0.78
1.32
bicarbonate ion
13.52
14.51
14.66
0.3
0.3
0.24
14.50
15.59
16.22
7.4
7.37
7.14
Form of transport
CO2 bound to protein
Total CO2 in plasma
pH of blood
[Source: Geers and Gros, Physiological Reviews (2000), 80, pages 681–715]
(a) Calculate the percentage of CO2 found as bicarbonate ions in the plasma of venous blood at rest.
(1)
(b) (i) Compare the changes in total CO2 content in the venous plasma due to exercise.
(1)
17. (ii) Identify which form of CO2 transport shows the greatest increase due to exercise.
(1)
18. (c) Explain the pH differences shown in the data.
(3)
(Total 6 marks)