Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > Exchange Surfaces and Breathing > Flashcards

Exchange Surfaces and Breathing Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are the main factors that warrant whether an organism needs a specialised exchange system?

A

Size

Surface area to volume ratio

Level of activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does the ‘size’ of an organism affect the need for an exchange system?

A

cytoplasm in small organisms is close to the environment so diffusion will supply enough oxygen and nutrients to keep the cells alive and active

Multicellular organisms may have several layers of cells and so anything diffusing in from the outside has a longer diffusion pathway meaning diffusion will be slow and won’t enable sufficient supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does ‘surface area to volume ratio’ affect an organism’s need for an exchange surface?

A

Some larger animals have small surface area to volume ratios which means it’s difficult to exchange enough substances to supply a large volume of animal with oxygen and nutrients through a small outer surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does an organism’s ‘level of activity’ affect its need for an exchange system?

A

Metabolic activity uses energy from food and requires oxygen to release the energy in aerobic respiration

If an organism is more active, its cells will need good supplies of nutrients and oxygen to supply the energy required for movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What features do all good exchange features have in common?

A

A large surface area to provide more space for molecules to pass through

A thin barrier to reduce the diffusion distance and that is permeable to the substances being exchanged

A good blood supply which can bring fresh supplies of molecules, to keep the concentration high or that can remove molecules to keep the concentration low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is a large surface area often achieved?

A

By folding the walls and membranes involved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why is a good blood supply important in a good exchange surface?

A

It maintains a steep concentration gradient so that fast diffusion can occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the gaseous exchange system in mammals consist of?

A

The lungs - 2 inflatable sacs lying in the chest cavity - and the associated airways that carry air into and out of them

Lungs are protected by the ribcage and the ribs are held together by the intercostal muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does air get from the environment into the body?

A

Air passes through the nose, along the trachea, from the back of the mouth to the lungs, down the bronchi and bronchioles, smaller airways leading into the lungs, it then reaches alveoli, folds of the lung epithelium, which is where gas exchange takes place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens during inspiration?

A

Diaphragm contracts and flattens, displacing the digestive organs

External intercostal muscles contract

Rib cage moves upwards and outwards

As volume of thorax increases, the lung pressure drops below atmospheric pressure and air is moved into the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens during expiration?

A

Diaphragm relaxes and is pushed up by displaced organs becoming curved

External intercostal muscles relax

Rib cage moves downwards and inwards

As volume of thorax decreases, the lung pressure rises above the atmospheric pressure and air is moved out of the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why must the lungs maintain a steep concentration gradient in each direction?

A

To ensure that diffusion can continue

The blood system transports CO2 from the tissues to the lungs ensuring the concentration in the blood is higher than that in the air of the alveoli - CO2 diffuses into alveoli

The blood transports O2 away from the lungs ensuring the concentration of O2 in the blood is kept lower than that in the alveoli - O2 diffuses into the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How are alveoli adapted for gaseous exchange?

A

Individually are very small but are numerous so have a large surface area to volume ratio

Lined by a thin layer of moisture which evaporates as we breathe out

Internally coated with a surfactant produced by the lungs to reduce the cohesive forces between water molecules preventing collapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the barrier to exchange comprised of?

A

The wall of the alveolus and the wall of the blood capillary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How are the lungs adapted to reduce the diffusion distance of gases?

A

Alveolus is one cell thick

Capillary wall is one cell thick

Both walls consist of squamous (flattened) cells

Capillaries are in close contact with alveolus walls

Capillaries are narrow so that red blood cells are squeezed against the capillary wall, making them closer to the air in alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does ventilation ensure?

A

The concentration of oxygen in the air of the alveolus remains higher than that in the blood

The concentration of carbon dioxide in the alveoli remains lower than that in the blood

The concentration gradient necessary for diffusion is maintained

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do the elastic fibres in the alveoli walls do?

A

They stretch during inspiration but recoil during expiration to help push air out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What requirements must the trachea, bronchi and bronchioles meet to be effective?

A

Be large enough to allow sufficient air to flow without obstruction

Be supported to prevent collapse when the air pressure inside is low during inspiration

Be flexible in order to allow movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What structure lines the airways?

A

Ciliated epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the function of ciliated epithelium?

A

It contributes to keeping the lungs healthy

Contains goblet cells which release mucus which traps pathogens

The cilia move the mucus to top of the airway where it’s swallowed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which is narrower, trachea or bronchi?

A

Bronchi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What prevents collapse of the airways during inspiration?

A

Rings of cartilage

C-shaped in the trachea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why is cartilage C-shaped in the trachea rather than a complete ring?

A

To allow flexibility and space for food to pass down the oesophagus

24
Q

What are the walls of the bronchioles comprised of?

A

Smooth muscle and elastic fibres

25
Q

What is the function of smooth muscle?

A

It can contract and so can constrict the airway making the lumen narrower

26
Q

When might controlling the flow of air to the alveoli be important?

A

If there are harmful substances in the air

When an allergic reaction is occurring

27
Q

What is the function of elastic fibres in the trachea?

A

To elongate the smooth muscle once it has contracted as it cannot reverse this effect on its alone

28
Q

Why must the smooth muscles relax before the elastic fibres can elongate them?

A

When the muscle is contracted the elastic fibres are deformed and cannot dilate the airways

29
Q

How do the elastic fibres dilate the airways after the contraction of smooth muscle?

A

As the muscles relax, the elastic fibres can recoil to their original size and shape thus dilating the air way

30
Q

What is a spirometer?

A

A device that measures the movement of air into and out of the lungs as a person breathes

31
Q

How do spirometers measure the movement of air in and out of the lungs?

A

A chamber of medical-grade oxygen with a lid floats on a tank of water

During inspiration, air is drawn from the chamber so that the lid moves down

During expiration, the air returns to the chamber and the lid is raised

Movements are recorded on a datalogger that is attached to the chamber lid to produce a trace

32
Q

How does a spirometer measure oxygen consumption?

A

The air exhaled is passed through a chamber of soda lime, which absorbs the carbon dioxide so that the volume of air in the chamber decreases

This decrease can be observed and measured on the spirometer trace and so measuring the gradient of the decrease in volume enables us to calculate the rate of oxygen uptake

33
Q

What precautions must be taken when using a spirometer?

A

The subject should be healthy and free from asthma

The soda lime should be fresh and functioning

There should be no air leaks in the apparatus as this would give inaccurate results

The mouthpiece should be sterilised

The water chamber must not be overfilled or water may enter the air tubes

34
Q

What is one advantage and one disadvantage of modern spirometers?

A

Advantage -
May be small and simple hand-held devices

Disadvantage -
Many cannot measure the rate of oxygen consumption

35
Q

What does the total lung volume consist of?

A

The vital capacity and the residual volume

36
Q

What is the vital capacity and how can it be measured?

A

It is the maximum volume of air that can be moved by the lungs in one breath

It is measured by taking a deep breath and expiring all the air possible from the lungs

37
Q

What factors does vital capacity depend upon?

A

The size of a person

The age and gender

Their level of regular exercise

38
Q

What region is vital capacity usually in?

A

2.5-5.0 dm3

39
Q

What is the residual volume?

A

The volume of air that remains in the lungs even after forced expiration - usually in the airways and alveoli

40
Q

What is the approximate measurement of residual volume?

A

1.5 dm3

41
Q

What is the tidal volume and when is it usually measured?

A

The volume of air moved in and out with each breath which is sufficient to supply all required oxygen

usually measured at rest

42
Q

What might a typical tidal volume be at rest?

A

0.5 dm3

43
Q

How can you calculate oxygen uptake from a spirometer trace?

A

One trace, draw a line from point A down to the horizontal axis and another line from point B to the horizontal axis

Measure the length of time between these points

Measure the different in volume between points A and B

Divide by the time taken for this decrease

The unit will be dm3 s-1

44
Q

How can you measure the breathing rate from a spirometer trace?

A

Count the number of peaks in each minute

45
Q

What will increase oxygen uptake result from?

A

Increased breathing rate

Deeper breaths

46
Q

What do bony fish use their gills for?

A

In order to absorb oxygen dissolved in the water and release carbon dioxide into the water

47
Q

What are a bony fish’s gills usually like?

A

Most have five pairs covered by the operculum

Each gill consists of two rows of primary lamellae attached to a bony arch

These lamellae are very thin and their surface is folded into many secondary lamellae providing a large surface area for where exchange takes place

48
Q

What arrangement in bony fish creates a countercurrent flow and what is its purpose?

A

Blood flows along the gill arch and along the lamellae to the operculum

Blood then flows through capillaries in the opposite direction to the flow of water over the lamellae creating a countercurrent flow

This arrangement absorbs the maximum amount of oxygen from the water

49
Q

How does ventilation work in bony fish?

A

Buccal-opercular pump keeps water flowing over the gills

The floor of the mouth moves downwards, drawing water into the buccal cavity

The mouth closes and the floor is raised again, pushing water through the gills

50
Q

How are the movements of the buccal cavity coordinated with movements of the operculum?

A

As water is pushed from the buccal cavity to the gills, the operculum moves outwards

This movement reduces the pressure in the opercular cavity, helping water to flow through the gills

51
Q

What kind of circulatory system do insects have?

A

A slow and open circulatory system in which the body fluid acts as both blood and tissue fluid

52
Q

What mechanism do insects possess that supplies air directly to all respiring tissues?

A

An air-filled tracheal system

53
Q

Describe an insects tracheal system and how gaseous exchange occurs

A

Air enters the system via a spiracle in each body segment

The air is transported into the body through a series of tubes called tracheae

These divide into smaller and smaller tubes called tracheoles which have open ends and the end are filled with tracheal fluid

Gaseous exchange occurs between the air in the tracheole and the tracheal fluid

54
Q

How can more oxygen be absorbed when the insect is active?

A

The tracheal fluid can be withdrawn into the body fluid in order the increase the surface area of the tracheole wall exposed to air

55
Q

How can larger insects ventilate their tracheal system?

A

By the movements of their body

56
Q

Describe 2 ways insects can ventilate using body movements

A

Sections of the tracheal system are expanded and have flexible walls, these act as air sacs which can be repetitively expanded and contracted to ventilate the tracheal system

Movements of the wings alter the volume of the thorax and as the volume decreases, air in the tracheal system is put under pressure and is pushed out of the tracheal system. When the thorax volume increases, pressure inside drops and air is pushed in from the outside

57
Q

How can locusts alter the volume of their abdomens by specialised breathing movements?

A

Their breathing movements are coordinated with opening and closing valves in the spiracles

As the abdomen expands, spiracles at the front end of the body open and air enters the tracheal system

As the abdomen reduces in volume, the spiracles at the rear end of the body open and air leaves the tracheal system

Biology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions