Gas exchange Flashcards
1
Q
What structures make up the human gas exchange system?
A
Lungs and air passages
The gas exchange system facilitates the exchange of oxygen and carbon dioxide.
2
Q
What is the primary function of the alveoli?
A
Gas exchange surfaces for oxygen and carbon dioxide
Alveoli allow oxygen to enter the blood and carbon dioxide to leave.
3
Q
Why is the gas exchange system located inside the body?
A
To protect delicate structures and prevent water loss
Air is not dense enough to support these structures.
4
Q
Name the first structure that air enters in the respiratory system.
A
Trachea
5
Q
What are the two main branches of the trachea called?
A
Bronchi
6
Q
What are the smaller airways called that branch from the bronchi?
A
Bronchioles
7
Q
What are the clusters of air sacs at the end of bronchioles called?
A
Alveoli
8
Q
What type of tissue is ciliated epithelium, and where is it located?
A
Tissue located throughout most airways
9
Q
What do goblet cells produce?
A
Mucus
10
Q
What is the function of cilia on ciliated epithelial cells?
A
Waft mucus upward to the mouth
11
Q
What keeps the trachea open?
A
Rings of cartilage
12
Q
What allows the trachea to change airflow?
A
Smooth muscle
13
Q
What type of epithelium lines the bronchi?
A
Ciliated epithelial cells and goblet cells
14
Q
What is a key adaptation of bronchioles?
A
No cartilage, can change shape
15
Q
What type of epithelium do larger bronchioles have?
A
Ciliated epithelium
16
Q
What is the primary function of alveoli?
A
Gas exchange
17
Q
How does oxygen enter the blood from the alveoli?
A
Diffuses into pulmonary capillaries
18
Q
What happens to carbon dioxide during gas exchange in the alveoli?
A
Diffuses from blood into the alveoli
19
Q
What adaptation allows rapid diffusion in alveoli?
A
Wall consists of one layer of squamous epithelial cells
20
Q
Why is a large surface area important for alveoli?
A
Increases rate of gas exchange
21
Q
What maintains a steep diffusion gradient in the alveoli?
A
Ventilation of air
22
Q
What is the function of elastic fibres in the alveoli?
A
Allow stretching and recoiling
23
Q
What do the pulmonary blood vessels include?
A
Pulmonary artery, pulmonary vein, pulmonary capillaries
24
Q
What is the role of the pulmonary artery?
A
Delivers deoxygenated blood to pulmonary capillaries
25
What adaptation of pulmonary capillaries maintains a short diffusion distance?
Thin walls (one endothelial cell thick)
26
True or False: Red blood cells are pressed against capillary walls to increase diffusion distance.
False
27
What does slow blood movement in pulmonary capillaries allow?
More time for diffusion
28
B
29
. Which structure, A to D, is not an example of a surface that is specialised for the purpose of gas
exchange?
A alveolus of a mammal
B plasma membrane of a unicellular protoctista
C leaf of a tobacco plant
D trachea of an insect
B
30
3. Bony fish absorb dissolved oxygen from the water using gills. Water is passed through the buccal cavity
and over the gill lamellae. The oxygen saturation of the blood and water changes as the water passes over
the gills.
Which of the statements, A to D, correctly describes the way oxygen is transferred into the blood at the gills?
A Blood and water flow in a concurrent system with a constant concentration gradient between them.
B Blood and water flow in a countercurrent system with a constant concentration gradient between them.
C Blood and water flow in a concurrent system with a greater concentration gradient between them at
the start of the gill lamella.
D Blood and water flow in a countercurrent system with a greater concentration gradient between them
at the start of the gill lamella.
B
31
Which of the following statements, A to D, correctly explains a feature of an efficient gaseous exchange
surface?
A The layers are thin for a short diffusion distance.
B There is a good blood supply, so the system reaches equilibrium quickly.
C There is an increased surface area to reduce surface area to volume ratio.
D Ventilation takes place to reduce concentration gradient of dissolved gases.
A
32
b
33
7. Ventilation is a process that involves various parts of the body.
Which of the following options, A to D, describes exhalation in a mammal?
A ribcage moves upwards and outwards; external intercostal muscles relax; diaphragm relaxes
B ribcage moves downwards and inwards; external intercostal muscles relax; diaphragm relaxes
C ribcage moves upwards and outwards; external intercostal muscles contract; diaphragm relaxes
D ribcage moves downwards and inwards; external intercostal muscles contract; diaphragm contracts
b
34
b
34
Like all amphibians, frogs are able to absorb oxygen through the skin as well as their lungs.
i. Suggest why the Titicaca water frog has evolved the unusually large folds of skin seen in Fig. 21.1.
Like all amphibians, frogs are able to absorb oxygen through the skin as well as their lungs.
i. Suggest why the Titicaca water frog has evolved the unusually large folds of skin seen in Fig. 21.1.
35
When out of the water, the Titicaca water frog is able to use its lungs to absorb oxygen.
Lungs contain specialised gaseous exchange surfaces.
Describe and explain how one feature of the lungs provides an efficient gas exchange surface.
D large surface area ✓
E for (maximum) diffusion ✓
D squamous, epithelium / cells
OR
alveolar wall, only 1 cell thick / thin ✓
E (providing) a short diffusion distance ✓
D good, blood supply / ventilation ✓
E maintaining / creating a (steep) concentration
gradient ✓
36
Volume C can be measured using an instrument such as a spirometer.
What breathing instructions would be given to a person whose volume C was being measured?
1 breathe in as deeply as possible / AW ✔
2 (and) then force as much air out as possible ✔
36
H ✔
D ✔
F ✔
C ✔
37
In Africa, closer to the equator, the mounds built by some species of termite are blade-shaped,
with the long axis pointing North–South. Fig. 5.2 shows an example of a termite mound in Africa.
Suggest why the African termites need to build mounds in this shape and orientation.
shape, large or increased surface area to volume
ratio (1)
smallest area exposed to greatest heat (1)
38
19. Many organisms have evolved specialised gas exchange surfaces. One feature of these
structures is their large surface area to volume ratio.
i. Describe how the structures of the insect tracheal system and fish gills provide a large surface area for
gas exchange.
insect tracheal system
Insects
many / branched, tracheae / tracheoles / tubes ✓
39
Many organisms have evolved specialised gas exchange surfaces. One feature of these
structures is their large surface area to volume ratio.
i. Describe how the structures of the insect tracheal system and fish gills provide a large surface area for
gas exchange FISH GILLS
Fish
many / AW , filaments / lamellae / plates✓
40
The lugworm, Arenicola marina, is a species of segmented worm that lives in burrows in damp sand.
They have hair-like external gills that increase the surface area available for gas exchange.
Many other species of segmented worm do not have external gills.
Suggest why lugworms have evolved external gills
oxygen is in short supply (in lugworm habitat) ✓
rate of diffusion is, insufficient / too slow (to meet
needs) ✓
lugworms have a smaller surface area to volume
ratio (than some worms) ✓
lugworms have a high(er) metabolic rate ✓
41
42
Ventilation of the lungs creates air movements that can be measured and recorded.
i. Name the apparatus used to measure and record these air movements.
spirometer ✓
43
). * Compare and contrast the mechanism of expiration during the first 60 seconds of the trace with
the mechanism of expiration when the subject was told to breathe out fully.
Normal expiration (provides some
comparative statements for similarities)
* passive
* diaphragm muscles relax
* diaphragm moves up / becomes
dome shaped
* external intercostal muscles relax
* ribs move down and in
* elastic fibres recoil
* volume of thorax reduced* pressure in thorax increased
* pressure in thorax greater than
atmospheric pressure so air
moves out of lungs
Forced expiration (provides contrasting
statements for differences)
* active
* requires energy
* internal intercostal muscles
contract
* ribs pulled down hard
* abdominal muscles contract
forcing diaphragm up
44
Complete the following statements about exchange surfaces.
Use the correct terms selected from the list below.
circulatory system concentration gradient diffusion pathway
flow of air Lung capacity Surface area
Surface area to volume ratio ventilation
Large organisms have a large .................................................................................... but they
have a small ...................................................................................... . This means they need
a specialised exchange surface and a ................................................................................... .
Two features of an efficient exchange surface are:
1. A good blood supply to maintain the......
2. A short ......
surface area ✓
surface area to volume ratio ✓
circulatory system ✓
concentration gradient ✓
diffusion pathway ✓
45
expalin how fish carry out inhalation and expiration
bony fish ventilation
water enters mouth
ref. volume / pressure, change in buccal
cavity
water, flows / pushed, over gills
water leaves via operculum
throughflow system / one direction of flow
bony fish gas exchange
gill, filaments / lamellae (shown on Fig. 6.2)
large surface area
thin
short diffusion distance
good blood supply / blood vessels (shown
on Fig. 6.2)
steep concentration gradient
counter current system (water and blood
move in opposite directions)
tips of gill filaments overlap to slow down
water movement
46
explain how insect carry out inhalation and expiration
insect ventilation
muscular movement
abdominal, dorso-ventral flattening /
telescoping / pumping
ref. volume / pressure, change in abdomen
thorax, movement / shape change, in flight
air drawn in or forced out
size of spiracle, changes / controlled
external gills in aquatic insects
small size / large SA:vol of insects, means
diffusion may be sufficient
insect gas exchange
gas / oxygen / CO2, diffuses along
tracheae (shown on Fig. 6.3)
oxygen dissolves in water at tracheoles
diffuses into surrounding cells
many tracheoles so large surface area
spirals of chitin (shown on Fig. 6.3) hold
tracheae open
47
. Adult flies have a very different body structure from that of maggots.
* Flies have complex and well-developed exchange surfaces and transport systems.
* Maggots have only a small number of tracheae and a small volume of tracheal fluid.
Suggest why maggots do not need such well-developed exchange surfaces and transport systems.
maggots are smaller so have greater surface area to
volume ratio (than adult flies) ✓
shorter diffusion distance ✓
idea that maggots less active so lower metabolic
demand for O2 ✓
no (hard) exoskeleton so can absorb oxygen by
diffusion through, skin / cuticle ✓
48
Describe how the trachea of a mammal is different from the trachea shown in Fig. 3.
1 mammals have just one trachea
and insects have multiple tracheae ✓
2 mammals (much) larger diameter /
insects (much) smaller diameter ✓
3 in mammals trachea has, cartilage / no chitin
(support)
and in insects tracheae have, no cartilage / chitin ✓
4 mammals have, C-shaped ‘rings’ / incomplete
circle,
and insects have spiral (support) ✓
5 mammal trachea is longer /
(individual) insect tracheae shorter ✓
6 mammal trachea branch into bronchi
and insect tracheae branch into tracheoles ✓
7 mammal trachea has,
smooth muscle / goblet cells / ciliated epithelium
and (individual) insect tracheae do not ✓
49
State the roles of cartialage in mammalian gas exchange.
cartilage
stops, trachea / bronchus, from collapsing ✓
50
State the roles of elastic fibres in mammalian gas exchange.
elastic fibres
recoil of, alveoli / air sacs ✓
51
*Outline the structures involved in the mammalian gaseous exchange system.
For each structure, explain how it increases the efficiency of gaseous exchange.
Nasal cavity
* large surface area and good blood
supply, warms air
* mucus secreting cells, trap dust
and microbes
* moist surfaces, increase humidity
and reduce evaporation from
surfaces in lung
Trachea
* cartilage rings, stop it from
collapsing
* ciliated epithelium and goblet cells
secrete mucus, trap dust and
microbes and move them towards
stomach * smooth muscle, allows air to move
in and out and maintains high
concentration gradient of O2 / CO2
Alveoli
* thin (epithelial) wall, reduces
diffusion distance
* collagen / elastic fibres, elastic
recoil to help squeeze air out
during exhalation
* large number / provide large
surface area, to increase rate of
diffusion
* good blood supply / capillaries,
maintains high concentration
gradient
* surfactant, allows gases to
dissolve
Diaphragm / intercostal muscles
* contract to increase volume in
lungs, reduce pressure and cause
inspiration
52
Ventilation involves various parts of the mammalian respiratory system.
Which of the following statements, A to D, describes inhalation?
A. ribcage moves upwards and outwards; external intercostal muscles relax; diaphragm relaxes
B. ribcage moves downwards and inwards; external intercostal muscles relax; diaphragm relaxes
C. ribcage moves upwards and outwards; external intercostal muscles contract; diaphragm contracts
D. ribcage moves downwards and inwards; external intercostal muscles contract; diaphragm
contracts
C
53
). Explain how Fig. 1.1 shows that gills are adapted for efficient gas exchange
three from
many / AW, lamellae / structure A, provide large
surface area (1)
(presence of) secondary lamellae on main lamellae
provide large surface area (1)
short distance between blood and, water / outside (1)
idea that blood maintains diffusion gradient (1)
4
any of above linked to
faster diffusion (of oxygen, carbon dioxide) (1
54
Why can expiration be a passive process?
it does not use muscle contraction / muscles (just)
relax
or
rib cage, falls / drops (due to gravity)
or
lungs (elastic so) will recoil ✔
55
(c). Each gill is supported by a gill arch made of bone. Bone tissue is made of living cells,
collagen and an inorganic component.
Explain why bone is described as a tissue and gills are described as organs.
three from
tissue has, one / few, types of cell and performs, one
/ few, functions (1)
idea that bone has, one / few, types of cell
or
idea that bone performs, one / few, functions (1)
organs consist of several tissues (1)
3
gills contain two or more named tissues (1)
56
Name the two types of epithelial tissue found in the lungs and airways.
1. Squamous epithelium
2. Ciliated epithelium
57
What happens when the rubber sheet is pulled down in the model of the mammalian chest?
The balloons expand.
58
Define tidal volume.
The volume of air inhaled or exhaled in a single breath.
59
How might a teacher demonstrate tidal volume using a model?
By showing the amount of air displaced by the balloons during a single breath.
60
Define vital capacity.
The maximum amount of air that can be exhaled after a maximum inhalation.
61
How might a teacher demonstrate vital capacity using a model?
By showing the total volume of air in the balloons after a deep breath.
62
What is the relationship between the rate of diffusion and the surface area to volume ratio?
As the surface area to volume ratio increases, the rate of diffusion also increases.
63
Explain the significance of the relationship between rate of diffusion and surface area to volume ratio for large plants.
Larger surface area to volume ratios allow for more efficient gas exchange.
64
List three reasons why a large, multicellular animal needs a transport system.
* To transport nutrients
* To remove waste products
* To distribute hormones
65
What is the full name given to a trace showing the electrical activity of the heart?
Electrocardiogram (ECG)
66
Identify component A in the heart.
Sinoatrial node (SA node)
67
Identify component B in the heart.
Atrioventricular node (AV node)
68
Why is there a delay between the excitation of the atria and ventricles?
To allow the atria to fully contract and fill the ventricles with blood.
69
Explain why the excitation wave is carried to the apex of the heart.
To ensure that the ventricles contract from the bottom upwards, effectively pumping blood out of the heart.
70
What measurement is represented by the line X in the lung volume graph?
Tidal volume
71
What happens to the elastic fibres in the walls of the alveoli at point A?
The elastic fibres stretch.
72
Using the data from Table 2.1, what is the surface area to volume ratio of the cube with 10 mm sides?
60:1000 or 0.06
73
What is the rate of diffusion for the 2 mm cube according to Table 2.1?
0.020 mm s−1
74
Suggest the method used to calculate the rate of diffusion in Table 2.2.
Time taken divided by volume.
75
State why the method used in Table 2.2 is not correct.
It does not account for the surface area.
76
Complete the adaptation: Squamous epithelium improves efficiency of gaseous exchange by _______.
[thinning the barrier for diffusion]
77
Complete the adaptation: A large number of alveoli improves efficiency of gaseous exchange by _______.
[increasing the surface area for gas exchange]
78
Complete the adaptation: A good blood supply improves efficiency of gaseous exchange by _______.
[maintaining a concentration gradient for oxygen and carbon dioxide]
79
Complete the adaptation: Good ventilation improves efficiency of gaseous exchange by _______.
[ensuring a constant supply of fresh air]
