3A Exchange and Transport Systems

Question 1

Figure 1 shows the filament of the fish.

Fill in the labels:
https://media.discordapp.net/attachments/352951793187029005/805146275426074634/unknown.png

Answer 1

A = Lamella

B = Capillary

C = Water flow

D = Gill Filament

Question 2

In a fish’s lamella, the flow of blood is located where?

Answer 2

Capillary

Question 3

In a fish’s gill filaments, the flow of water is left. What is the direction of the flow of blood?

Answer 3

Right

Question 4

List two features the gill filament has and how it helps the fish with gas exchange.

Answer 4

The lamella on the gill filament give it a high surface area to volume ratio, increasing the rate of gas exchange.

The gill filament uses a countercurrent system which means that blood cells can become fully oxygenated despite getting oxygen by diffusion.

Question 5

Explain how a countercurrent system leads to blood cells which are fully oxygenated.

Answer 5

In the gill filament of a fish, water flow is opposite to the flow of the blood.

The reason for this is because, as blood goes down the capillaries, it will constantly find new oxygenated water cells coming from the other side and so a constant concentration gradient is established, meaning blood cells do not reach equilibrium with the water until it becomes fully oxygenated, to which it can be sent to the rest of the body.

Question 6

Explain how a system where water flow is the same direction as blood flow leads to blood cells only having the potential to get about 50% oxygen content by diffusion.

What are the consequences of this if it were to be true for the fish?

Answer 6

If, in the gill filament of a fish, water flow is the same direction as blood flow, blood travels down the capillary and a concentration gradient is not constant and eventually decreases.

Since the concentration gradient between the blood and water decreases as you go across the lamella, this means the rate of oxygen exchange will decrease meaning that blood can only have a maximum of 50% oxygen content.

This can be dangerous to the fish, as less oxygen will be delivered to their cells meaning the fish may suffer from tiredness that may turn extreme.

Question 7

Name A and name B:

https://media.discordapp.net/attachments/352951793187029005/805151433099575306/unknown.png

Answer 7

A = Water
B = Blood

Question 8

In insects, what are tracheae?

Answer 8

Tracheae are microscopic, air-filled pipes used for gas exchange.

Question 9

In insects, what are spiracles?

Answer 9

Spiracles are small, circular pores on insects which supply air into tracheae.

Question 10

In insects, what are tracheoles, and how are they adapted to deliver diffusion quickly?

As well as this, cells have a product of carbon dioxide which must be removed during respiration. How do they get released?

Answer 10

Tracheoles are branches which sprouted off tracheae that are responsible to deliver oxygen to respiring cells.

Tracheoles are one cell thick which means that the diffusion pathway is very short meaning gas exchange occurs faster.

In insects, carbon dioxide, once released, moves down it’s own concentration gradient to the spiracles to be released to the atmosphere.

Question 11

How do insects move air in and out the spiracles?

Answer 11

Insects have rhythmical abdominal movements which allow the movement of gases in and out the insect.

Question 12

Name A,B and C.

https://media.discordapp.net/attachments/352951793187029005/805160065794703370/unknown.png

Answer 12

A = Spiracle

B = Tracheae

C = Tracheole

Question 13

List features of the insect which help the insect control water loss.

Answer 13

Spiracles can open and close, and so when they close the rate of water loss will be lower as they have less places to escape from.

There is a waxy, waterproof cuticle around the insect, which lowers the rate of evaporation.

There are hairs on the spiracles which trap water.

Question 14

What is the main part of the plant cell responsible for gas exchange?

Answer 14

Mesophyll

Question 15

Explain an adaptation of spongy mesophyll and how this adaptation allows the plant to have faster gas exchange.

Answer 15

Spongy Mesophyll often feature large spaces of empty air.

These spaces allow oxygen and carbon dioxide to diffuse in and out of the leaves easily.

Question 16

What part of the plant cell lets gases in and out?

Answer 16

Stomata

Stomata = plural, stroma = singular

Question 17

Where are stomata located?

Answer 17

The epidermis

Question 18

What allows stomata to open or close?

Answer 18

Guard cells

Question 19

How do stomata close when water concentration gets low, and how do stomata open when water concentration gets high?

Answer 19

Guard cells control the entry of gases into the stroma physiologically.

For example, when water concentration is high in the stroma, guard cells will become turgid and will enter the stomata by osmosis, opening up the stroma.

However, when water concentration is low in the stroma, guard cells will become flaccid and will leave the stomata by osmosis, closing the stroma.

Question 20

Explain the features of the waxy cuticle in insects and plants and how it helps to prevent water loss.

Answer 20

A waxy cuticle is a layer which is on top of the epidermis in plants and on top of insects. It is waterproof and thick and so water loss becomes harder as any that evaporate will find it harder to leave the organism.

The waxy cuticle also has hairs which are mostly present in insects and xerophytic plants which trap moist air. In xerophytic plants, the ability to trap moist air means that there is less water loss by osmosis as the concentration gradient is lower than dry air.

In insects, hairs on the waxy cuticle basically share the same purpose near spiracles.

Question 21

List 3 features of xerophytic plants which allow them to survive in hot, dry and windy conditions.

Answer 21

Xerophytic plants are curled up, which traps moist air as the collision and entry of dry air is much less likely. Due to this, xerophytic plants will lose less water from the stomata being open as there is a lower concentration gradient between the moist air and the water in the stomata.

Xerophytic plants have many hairs on their waxy cuticle near stomata which allow the trapping of moist air, which again decreases the concentration gradient.

Xerophytic plants have a reduced number of stomata so when they are open less water loss is caused all together.

Waxy, waterproof cuticles on leaves reduces evaporation.

Question 22

What is the formula for volume in a cube?

Answer 22

x^3

This is because all the sides in a cube are equal so we can account them for the same algebraic expression.

x = cube measurement (e.g. 4 cm)

Question 23

What is the formula for surface area in a cube?

Answer 23

6(x^2)

Assuming the cube has 6 sides.
x = cube measurement (e.g. 4 cm)

It is squared because all the sides in a cube are equal so 2^2 = 2x2 etc

Question 24

The link given is a picture of a cube:

https://media.discordapp.net/attachments/352951793187029005/805174454710960249/unknown.png

Give the surface area and volume.
Find the surface area to volume ratio.

Answer 24

Volume = 4^3 = 64

Surface area = 6(4^2) = 6(16) = 96

1.5:1

Divide both sides by volume to get the surface area to volume ratio.

64 / 64 = 1
96 / 64 = 1.5

Question 25

The link given is a picture of a rectangle:

https://media.discordapp.net/attachments/398978977483456524/805177251582574602/unknown.png

Find the surface area and volume.
Find the surface area to volume ratio.

Answer 25

Volume = Length x width x height

Because there are 4 variables, you should have deducted that the ‘6’ represents the width and the ‘3’ represents the height and length.

6 x 3 x 3 = 54cm^2

The surface area is separated into two different formulas because this is a rectangle, not all shapes are equal.

There are 4 long sides on the rectangle with 6 width and 3 height. You should have deducted that as a result the surface area of the 4 long ones are:

4(6x3) = 72cm^2

The surface area of the two smaller cubes show that they consist of a width of 3 and a height of 3. Therefore, the surface area is:

2(3x3) = 18

18 + 72 = 90cm^3

The surface area to volume ratio can be deducted by dividing both sides by volume.

90 / 54 = 1.66

54/54 = 1

1.66:1

Question 26

The link given is a picture of a rectangle:

https://media.discordapp.net/attachments/398978977483456524/805179411728695356/unknown.png

Find the surface area and volume.
Find the surface area to volume ratio.

Answer 26

From the image, you should have deducted that the width is 10 and the length and height is 2.

2 x 2 x 10 = 40cm^2

From there, to find the surface area, it must be deducted into 2 formulas because not all the sides are fully equal. The wide parts which show in 4 sides of the rectangle out of the 6 total sides have a height of 2 and width of 10.

You can use this to find out the surface area of these:

4(2x10) = 80

To find the surface area of the 2 smaller sides, the height is 2 and the width is 2:

2(2x2) = 8

8 + 80 = 88cm^3

Divide both sides by volume:

40 / 40 = 1
88 / 40 = 2.2

2.2:1

Question 27

Label A to J:

https://media.discordapp.net/attachments/352951793187029005/807215388987097129/unknown.png?width=808&height=563

Answer 27

A = Nasal cavity
B = Nostril
C = Trachea
D = Bronchus 
E = Right Lung

F = Band of muscle
G = Bronchiole
H = Pulmonary Artery
I = Alveoli
J = Network of capillaries on alveoli
K = Pulmonary Vein

Question 28

What’s a bronchi and bronchiole?

Answer 28

Bronchi are tubes which separate from the trachea - there are two of them and each one goes to different lungs and are responsible for the transport of gases through each lung. They produce mucus to trap dirt particles, as well as cilia.

Bronchioles are branches from the bronchi which get thinner and thinner to reach every single alveoli for gas exchange to the blood. They are made of muscle lined with epithelial cells.

Question 29

What is ventilation?

Answer 29

Ventilation is the action of expiration and inspiration (breathing in and out).

Question 30

What is the trachea?

Answer 30

The trachea is a flexible airway that is supported by rings of cartilage. The tracheal walls are made of muscle, lined with ciliated epithelium and goblet cells.

Question 31

What are the lungs?

Answer 31

The lungs are a pair of lobed structures which are made up of a series of highly branched bronchioles which expand to alveoli - tiny air sacs which facilitate gas exchange between the blood.

Question 32

What is an alveoli?

Answer 32

The alveoli is a minute air sac present in the lungs. Oxygen-rich air will travel there by the bronchioles to supply oxygenated blood into the millions of capillaries which are around it, through it’s very thin alveolar membrane.

Question 33

List, in the correct sequence, all the structures which are present when air travels through the body, starting from the gas exchange surface of the lungs to the nose.

Answer 33

Alveoli
Bronchioles
Bronchi
Trachea
Nose

Question 34

Label A to F - the structure of the lungs:

https://media.discordapp.net/attachments/352951793187029005/807238654224629770/unknown.png

Answer 34

A = Cilia
B = Basal Granule
C = Cell Membrane
D = Goblet cell
E = Nucleus
F = Basement Membrane

Question 35

Explain how the cells lining the bronchus (plural for bronchi) and trachea protect the alveoli from damage.

Answer 35

Goblet cells produce mucus that trap particles of dirt and bacteria breathed in.

The cilia in the cells then waft up the dirt/bacteria up the trachea into the stomach, so they are not in the alveoli.

This is needed as the dirt/bacteria, if put inside the alveoli, could damage it.

Question 36

Describe what happens to the body as you breathe in (Inspiration).

Answer 36

Internal intercoastal muscles relax.
External intercoastal muscles contract.

Diaphragm flattens, contracting (unrelaxed).
As a result of this, the thoracic cavity increases as there is more space in the lungs for air to come in. This decreases pressure in the lungs.

Ribcage moves up and out.
Lung pressure decreases to atmospheric pressure
Air flows to lungs with the pressure gradient

Active - requires energy

Question 37

Describe what happens to the body as you breathe out (Expiration).

Answer 37

Internal intercoastal muscles contract.
External intercoastal muscles relax.

Diaphragm becomes curved and goes in, becomes relaxed
Due to this, the volume of the thoracic cavity decreases, increasing the pressure of the air inside the lungs.

Ribcage goes down and in, relaxed

Lung pressure increases to above atmospheric pressure

Air is forced down the pressure gradient and out of the lungs

Passive - does not require energy

Question 38

Describe 3 differences between Inspiration and Expiration.

Answer 38

In Inspiration, internal intercoastal muscles relax and external intercoastal muscles contract. This is the opposite in expiration

In expiration, the ribcage goes down and in (relaxes). This is the opposite in Inspiration where the ribcage goes up and out.

Inspiration requires energy. Expiration does not

In Inspiration, the diaphragm contracts and flattens. This is the opposite in expiration where the diaphragm relaxes and curves up against the lungs.

Question 39

Which action, expiration or inspiration?

External intercoastal muscles contract

Answer 39

Inspiration

Question 40

Which action, expiration or inspiration?

Diaphragm contracts to increase the volume of the chest

Answer 40

Inspiration

Done to allow more air in

Question 41

Which action, expiration or inspiration?

The ribcage drops inwards and downwards

Answer 41

Expiration

Question 42

Which action, expiration or inspiration?

Air is pushed into the lungs

Answer 42

Inspiration

Question 43

Which action, expiration or inspiration?

The pressure inside the chest increases

Answer 43

Expiration

Question 44

A person wanted to cut the exoskeleton of a grasshopper.

What piece of equipment is needed for this?

Answer 44

Dissecting Scissors

Question 45

Lepus Capenses and Lepus Othus are two types of hare.

Lepis Othus has relatively short ears compared to Lethus Capensis.

Which of these two hare species would you expect to find in Alaska, where the climate is cold?

Explain your answer.

Answer 45

Lepis Othus

This is because having shorter ears compared to your counterpart gives you a lower surface area to volume ratio. This means you lose heat at a slower rate.

Since you lose heat at a slower rate, you are more adapted to function in a cold environment and can survive better.

Question 46

Alaskan hares are hunted by larger mammals, such as polar bears.

Explain how you would expect the metabolic rate of an Alaskan hare to differ from the metabolic rate of a polar bear.

Answer 46

The Alaskan hares will have a higher metabolic rate than the polar bears as they are small, featuring a higher surface area to volume ratio.

Since they have a high SA:V ratio, heat loss is much more frequent, meaning that they need to have a higher metabolic rate to release enough heat to maintain a constant body temperature.

Polar bears are larger and have more compact faces, meaning they have a lower SA:V ratio. This means that heat loss occurs much slower and so the rate of metabolism decreases as it releases enough heat to maintain it’s constant body temperature.

Question 47

Label A to M:

https://media.discordapp.net/attachments/352951793187029005/810982174563106856/unknown.png

Answer 47

A = Upper Epidermis
B = Chloroplast
C = Veins (Vascular Bundle)
D = Lower Epidermis
E = Air Space in Spongy Mesophyll
F = Open Stomata
G = Guard Cell
H = Waxy Cuticle
I = Spongy Mesophyll
J = Mesophyll
K = Palisade Mesophyll
M = Waxy Cuticle

Question 48

What is the Waxy Cuticle?

Answer 48

A waxy cuticle is a waterproof, thick layer featured on the surface of plants and insects.

Question 49

What consists of the epidermis in plant cells?

Answer 49

The epidermis consists of a waxy cuticle and a transparent layer of cells with no nucleus in which light can pass through.

Question 50

In the Epidermis, there is a waxy cuticle. What else is there under?

Answer 50

A layer of cells with no nucleus

Question 51

A layer of wide, long cells with no nucleus are seen under the waxy cuticle as part of the epidermis.

How can they help the leaf with survival?

Answer 51

The cells are made as more of a last ditch resort to make sure the leaf’s internal structures do not get destroyed by creating a gap between the actual leaf’s organelles and the organism eating it.

Question 52

Give an adaptation of Palisade Mesophyll.

Answer 52

They have a high SA:V ratio, meaning that the rate of photosynthesis is higher.

They are packed with chloroplasts, meaning the rate of photosynthesis is also higher.

Question 53

Outline two features of xerophytic plants inferred from the diagram that decreases the rate of water loss:

https://media.discordapp.net/attachments/352951793187029005/810985081317490718/unknown.png

Answer 53

Stomata sunken in pits, traps moist air to once again decrease concentration gradient between the stomata and the water in the environment, leading to less water loss by osmosis

Hairs on the lower epidermis trap water, making the air more moist, decreasing the concentration gradient between the water in the stomata and the water in the environment, leading to less water loss by osmosis

Leaves curled up in order to trap moist air, as well as trap dry air from coming in

Question 54

Explain the adaptations single-celled organisms have regarding gas exchange.

Answer 54

Single-celled organisms exchange gases through their body surface.

This is because they are very simple organisms - they have a very high surface area to volume ratio and are often very thin, having a very low diffusion pathway.

This means, for single celled organisms, simple diffusion is sufficient for gas exchange - no system is really needed.

Question 55

Describe the process of gas exchange when an insect is resting, from the spiracles to the cells.

Answer 55

Firstly, oxygen will move into the insect’s tracheae by spiracles, small pores in the insect.

Once the oxygen is in the tracheae, it will travel down the concentration gradient through smaller and smaller branches, known as tracheoles.

These tracheoles will keep branching off until they reach a cell - tracheoles are small air-filled pipes which supply oxygen to each cell.

When oxygen reaches the cell from the tracheoles, it will enter directly by diffusion to the respiring cells.

Question 56

How does the insect expel the waste product of carbon dioxide?

Answer 56

In insects, carbon dioxide, once released, moves down it’s own concentration gradient to the spiracles to be released to the atmosphere.

Rhythmical abdominal movements are used to expire the carbon dioxide from the system by increasing the pressure inside the system to actively force it out.

Question 57

Describe why a smaller animal [e.g. rat] needs a higher metabolic rate than a larger one [e.g. hippo].

Answer 57

Hippos have a very low surface area to volume ratio and as a result they don’t lose heat as fast.

In contrast, rats have a very high surface area to volume ratio and as a result they lose heat very fast.

Due to this, rats need higher metabolism in order to maintain warmth in their bodies, as they lose temperature must faster.

Question 58

What would have a higher surface area?

Hippo / Rat

Answer 58

Rat

Question 59

What would have a higher surface area?

Large ears / Small ears

Answer 59

Large ears

Question 60

Explain why larger animals like horses need to have a gas exchange system in order to deliver oxygen to all the cells in their body, when unicellular organisms don’t.

Answer 60

Unicellular organisms use the surface of their body to transport gases like oxygen and carbon dioxide in and out.

This is because they have a very high SA:V ratio and are very thin, so there is a very small diffusion pathway between the whole organism. Due to this, they don’t need a gas exchange system and can survive by simple diffusion.

Compared to horses, some cells in horses have a very high diffusion pathway from the environment, usually because the cells are deep inside the horse and gases can’t reach there.

Due to this, horses, with a lower SA:V ratio than unicellular organisms, must have a dedicated gas exchange system to deliver oxygen to all the cells inside them.

Question 61

Find the surface area and volume of this cylinder:

https://media.discordapp.net/attachments/794561815660986431/810997432077779034/unknown.png

πr²h = Volume
2πr(h+r) = Surface Area

Find the SA:V ratio.

Answer 61

Volume = π * 196 * 42

r = 14
r² = 14 x 14 = 196

42 = h

= 25861.5907244

Surface area = 2 * π * 14(42+14)

r = 14
h = 42

= 4926.01728083

4926. 01728083 : 25861.5907244
4927. 01728083 / 25861.5907244 = 0.19
4928. 19:1 | SA:V

Question 62

Find the surface area and volume of this cylinder:

https://media.discordapp.net/attachments/352951793187029005/811330227174637598/unknown.png

πr²h = Volume
2πr(h+r) = Surface Area

Find the SA:V ratio.

Answer 62

Volume = π * 100 * 35

10 x 10 = 100

= 10995.5742876

Surface Area = 2 * π * 10(35+10)

= 2827.43338823

2827. 43338823 : 10995.5742876
2828. 43338823 / 10995.5742876 = 0.257
2829. 26:1 | SA:V

Question 63

List two things organisms need to exchange with the environment.

Answer 63

Oxygen
Nutrients
Urea
Excrement (Waste)
Water

Question 64

Describe how body shape affects heat exchange.

Answer 64

The shape of the organism’s body can affect certain variables, such as surface area, which can affect how heat is exchanged with the environment.

For example, a body shape which features a high surface area to volume ratio, such as wide, long ears or a smaller size, heat exchange occurs faster within the environment.

In contrast, a body shape which features a small surface area to volume ratio such as a massive size and very small ears (compact) causes heat exchange to occur slower.

Question 65

What are the intercoastal muscles?

Answer 65

The intercoastal muscles refer to the two layers of muscles in the ribcage, both external and external.

Question 66

Describe the journey of air from the nostrils right to the gas exchange surfaces inside the lungs.

Answer 66

Firstly, air enters the individual by either the mouth or the nostril.

Air then travels down the trachea and reaches the bronchi, which branch from the trachea to lead to either lung.

Air goes down one of the bronchi into the lungs, and the bronchi constantly branches off into smaller tubes, known as bronchioles.

Bronchioles end in small ‘air sacs’ called alveoli. When air reaches the alveoli, it enters by diffusion through it’s thin alveolar membrane and is the site of gas exchange.

Question 67

What is ventilation?

Answer 67

The exchange of air between the lungs and the atmosphere; it is achieved by the physical act of
Expiration and Inspiration (Breathing out & Breathing in).

Question 68

Why is the action of ventilation essential to efficient gas exchange?

Answer 68

Because gas exchange is a passive process, a ventilation system is needed to maintain a concentration gradient within the alveoli, in which it exchanges air to and from the environment in order to keep oxygen levels high and carbon dioxide levels low.

The concentration gradient being maintained by ventilation allows for more efficient gas exchange, as the concentration of oxygen becomes higher on average, allowing for all cells to be supplied more oxygen at once to be able to generate more energy when respiring.

Question 69

Label B to M:

https://media.discordapp.net/attachments/352951793187029005/811668399791931433/unknown.png

Words needed to help:

Blood Plasma
Pulmonary Capillary
Alveolar duct
Moist alveolar surface
Endothelial cell of capillary
Exhaled air
Inhaled air
Alveolus cavity
Epithelial cell of alveolus
High CO2 Concentration
Carbon dioxide into alveoli
Oxygen into blood

Answer 69

B = High CO2 Concentration
C = Endothelial cell of capillary
D = Blood Plasma
E = Pulmonary Capillary
F = Moist alveolar surface
G = Epithelial cell of alveolus
H = alveolar duct
I = Exhaled air
J = Inhaled air
K = Alveolus cavity
L = Carbon dioxide into alveoli
M = Oxygen into blood

Question 70

List two things that the blood does to maximize gas exchange near the alveolus.

Answer 70

Pulmonary capillaries which are near the alveoli are very narrow, and as a result of this, blood in the capillaries get flattened against the capillary wall. This decreases the diffusion pathway needed for oxygen to get into the blood.

Red blood cells in the pulmonary capillaries are slowed down, giving more time for gases to be exchanged between each other to maximize efficiency

Question 71

List three features of the lungs which make it fit for efficient gas exchange.

Answer 71

Lungs have an extremely high amount of alveoli, approximately 300 million in each lung.
This means that the lungs consist of gas exchange sites which have an extremely high surface area to volume ratio, allowing for gas exchange to be rapid and efficient.

The alveoli in the lungs have extremely thin epithelial cells, lined with capillaries containing blood with extremely thin endothelial cells, both being one cell thick. This allows for a very small diffusion pathway between the gases the two, meaning that gas exchange is fast and efficient.

The alveoli are surrounded by a very dense network of capillaries, maintaining a steep concentration gradient of oxygen and carbon dioxide between the air and the blood.

Alveoli are extremely small and have a very high SA:V ratio, allowing for more rapid gas exchange between oxygen and carbon dioxide.

Question 72

List two factors which contribute to the rate of gas exchange.

Answer 72

Thickness of the diffusion pathway (gas exchange surface)

The difference in concentration between the two conditions being diffused (Concentration gradient)

Surface area

Question 73

Describe what happens to the diaphragm between times P and Q to bring the change in it’s shape:

https://media.discordapp.net/attachments/352951793187029005/811685624540168192/unknown.png

Air moves into the lungs between times P and Q. Explain how the diaphragm causes this.

Answer 73

On diagram P, the diaphragm is relaxed, forming a curved structure.
On diagram Q, the diaphragm contracts, flattening.

On diagram P, the diaphragm becomes relaxed, forming a curved structure which decreases the volume of the thoracic cavity, which decreases the volume of the lungs.

Since the volume of the lungs are decreased, the pressure increases in the lungs to above atmospheric pressure, forcing carbon dioxide out of the lungs down the pressure gradient.

On diagram Q, the diaphragm contracts, forming a flattened structure which increases the volume of the thoracic cavity, which increases the volume of the lungs in order to allow more air in for inspiration.

Since the volume of the lungs are increased, the air pressure decreases to atmospheric pressure allowing air inside, down the pressure gradient.

Question 74

Describe how oxygen in the alveoli enters the blood in the capillaries.

Answer 74

The oxygen enters the capillaries by diffusion, down the concentration gradient.

The oxygen diffuses through the thin, epithelial walls of the alveoli as well as through the thin, endothelial walls of the capillaries to enter directly into the blood.

Question 75

Explain a reason why oxygen and carbon dioxide are able to diffuse across membranes.

Answer 75

Oxygen and carbon dioxide do not consist of water, and so can pass through the phospholipid bilayer of the cell membrane, including the hydrophobic tails just fine.

Oxygen and carbon dioxide are small molecules, and so do not need to be transported by carrier proteins.

Oxygen and carbon dioxide are not polar, allowing them to pass through the membrane as well.

Question 76

What is Tidal Volume?

Answer 76

Tidal Volume refers to the volume of air breathed in and out of the lungs during each breath.

Question 77

What is Ventilation Rate?

Answer 77

Ventilation Rate refers to the number of breaths per minute.

Question 78

What is Forced Expiratory Volume?

Answer 78

Forced Expiratory Volume is the maximum volume of air that can be breathed out in 1 second.

Question 79

What is Forced Vital Capacity?

Answer 79

Forced Vital Capacity is the maximum amount of air that is possible to breathe forcefully out of the lungs after a really deep breath in.

Question 80

How many centimeters are needed to make 1 decimeter?

Answer 80

10cm = 1dm

Question 81

How many centimeters are needed to make 1 dm³?

Answer 81

1dm = 10cm
10³ = 10 x 10 x 10 = 1,000

1,000cm = 1dm³

Question 82

From the graphs shown, calculate the breathing rate of this person:

https://media.discordapp.net/attachments/352951793187029005/811692230409977866/unknown.png

Give your answer in breaths per minute.

Answer 82

The difference in the time between the 2 spikes in lung volume (showing that it increased to allow air in indicating breathing) is 3.5 seconds.

This indicates one breath (from when it starts to the start of another).

1 breath happened in 3.5 seconds. Divide 60 by 3.5 = 17.142

Pulmonary Ventilation = 17dm³

Question 83

If the volume of air in the lungs when the person inhaled was 3,000 cm³, calculate the volume of air in the lungs after the person had exhaled.

Use the graphs to help you:

https://media.discordapp.net/attachments/352951793187029005/811692230409977866/unknown.png

Answer 83

Firstly, breathing volume is measured in dm³ so convert cm³ to dm³

3,000cm³ = 3dm³

The y axis in the first graph says “change in lung volume/dm³” - the spikes in the graph you should have realized are inhalation.

Counting the squares makes you realize the peak in the first graph is at 0.48dm³, showing that the ‘change in lung volume’ was an addition of 0.48dm³ when the person inhaled.

We are told that the volume of lungs when the person inhaled is 3dm³, and we now realize that it was a change in lung volume from an increase of 0.48dm³, meaning the original value was 2.52dm³.

When you exhale, alveolar pressure increases and lung volume decreases. It gets to its lowest, at 0.00, meaning that the volume of air in the lungs when the person exhaled is 2.52dm³.

Question 84

Explain how muscles create the change of pressure in the alveoli over the period of 0 to 0.5s.

Use the graph to help you:

https://media.discordapp.net/attachments/352951793187029005/811696839463534632/unknown.png

Answer 84

The diaphragm contracts, causing it to flatten. This allows the thoracic cavity to increase in volume, increasing the lung volume which makes the air pressure decrease to atmospheric pressure.

As well as this, the intercoastal external muscles contract, causing the ribcage to move up and out, consequently decreasing atmospheric pressure in the alveoli as lung volume increases even more.

Question 85

What instrument must be used to measure tidal volume and ventilation rate?

Answer 85

Spirometer

Question 86

Calculate the total amount of air breathed in and out per minute when the cyclist is at 20km/h:

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Answer 86

Breathing rate = 20/min
Tidal volume = 2.75dm³

2.75 x 20 = 55dm³/min

Question 87

What is Fibrosis?

Include:

How it’s caused
Symptoms

Answer 87

Fibrosis is the formation of scar tissue in the lungs. This can be the result of an infection or exposure to substances like asbestos or dust.

Scar tissue is thicker and less elastic than normal lung tissue, which means that the lungs are less able to expand and so can’t hold as much air as normal - tidal volume is reduced, and so is FVC (a smaller volume of air can be forcefully breathed out).

Symptoms of fibrosis include shortness of breath, a dry cough, chest pain, fatigue and weakness.

Question 88

What is Asthma?

Include:

How it’s caused
Symptoms

Answer 88

Asthma is a respiratory condition where the airways become inflamed and irritiated, as a result of an allergic reaction.

During an asthma attack, the smooth muscle lining the bronchioles contracts and large amount of mucus is produced.

This causes constriction of the airways, making it difficult for the sufferer to breathe properly. Air flow in and out of the lungs is severely reduced, so less oxygen enters the alveoli and moves into the blood, reduced air flow means the forced expiratory volume is severely reduced (less air can be breathed out in 1 second).

Symptoms include wheezing, a tight chest and softness of breath. This can be relieved by drugs (often in inhalers).

Question 89

What is Emphysema?

Include:

How it’s caused
Symptoms

Answer 89

Emphysema is a lung disease caused by smoking or long-term exposure to air pollution - foreign particles in the smoke (or air) become trapped in alveoli.

This causes inflammation, which attracts phagocytes to the area, and the breakdown of elastin (a protein found in the walls of the alveoli).

Elastin is elastic - it helps the alveoli to return to their normal shape after inhaling and exhaling air.

Loss of elastic means that the alveoli can’t recoil or expel the air as well, means some air is trapped in the alveoli.

It leads to the destruction of the alveoli walls, which reduces the surface area of the alveoli, so the rate of gaseous exchange decreases.

Symptoms of emphysema include shortness of breath and wheezing. People with emphysema have an increased ventilation rate as they try to increase the amount of air containing oxygen reaching the lungs.