Brainscape's Knowledge GenomeTM

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


See full index

AS OCR Biology > Unit 3.1- Exchange surfaces > Flashcards

Unit 3.1- Exchange surfaces Flashcards

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

How does the size of the organism relate to the SA/V ratio?

A

Larger organisms have a smaller SA/V ration than smaller organisms.

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

Why can’t we survive on diffusion alone?

A

Cells in the centre of organisms would not receive any materials

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

What type of metabolic rate do multicellular organisms have?

A

High. This is because lots of materials need to be exchanged fast.

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

What factors influence gas exchange systems in mammals?

A
  • Blood supply
  • SA
  • Ventilation
  • Thickness of layers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does blood supply relate to gas exchange surfaces in mammals?

A
  • Helps to keep a steep concentration gradient so gasses continue to diffuse
  • The blood transports the substances so the concentration is maintained
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does a large surface area relate to gas exchange surfaces in mammals?

A
  • Provides more space for molecules to pass through
  • The alveoli all together have a larger surface area than our skin
  • They are lined by a thin layer of moisture (surfactant) which evaporates as we breathe out. This reduces the cohesive forces between the water molecules as this can cause the alveoli to collapse.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does ventilation relate to gas exchange surfaces in mammals?

A
  • The movement of the lungs brings in oxygen and gets rid of carbon dioxide
  • The concentration of oxygen in the air of the alveoli remains higher than in the blood, which enables it to diffuse. The concentration of carbon dioxide is lower in the lungs.
  • Therefore the concentration gradient is maintained.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do thin layers relate to gas exchange surfaces in mammals?

A

These are adaptations to reduce the diffusion distance:

  • The alveolus wall is 1 cell thick
  • The capillary wall is 1 cell thick
  • Both walls consist of squamous cells (flattened or very thin)
  • The capillaries are in close contact with the alveolus walls
  • The capillaries are narrow so the RBC are squeezed against the walls
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does inspiration happen?

A
  • The diaphragm contracts to move down and become flatter
  • The external intercostal muscles contract to raise the ribs
  • The volume of the chest cavity is increased
  • The pressure in the chest cavity drops below atmospheric pressure, so air is moved into the lungs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does expiration happen?

A
  • The diaphragm relaxes and is moved up
  • The external intercostal muscles relax and the ribs fall
  • The internal intercoastal muscles can contract to push air out more forcefully (usually just in exercise or when coughing or sneezing)
  • The volume of the chest cavity is decresed
  • The pressure in the lungs increases above atmospheric pressure so air is forced out of the lungs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Cartilage definition:

A

A form of connective tissue

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

Ciliated epithelium definition:

A

A layer of cells that have many hair-like projections called cilia

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

Elastic fibres definition:

A

Protein fibres that can deform and then recoil to their original size

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

Goblet cells:

A

Cells that secrete mucus

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

Smooth muscle definition:

A

Involuntary muscle that contracts without the need for conscious thought

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

Why are the airways of the trachea and the bronchi supported by rings of cartilage?

A

It prevents collapse during inspiration

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

Why are the rings of cartilage in the trachea C shaped rather than a complete circle like in the bronchi?

A

It allows flexibility and space for food to pass down the oesophagus

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

What are the walls of bronchioles made of?

A
  • Larger ones may have some cartilage

- Smaller don’t have cartilage but the wall is made of smooth muscle and elastic fibres

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

Where are ciliated epithelium?

A

They line the airways of the trachea, bronchi and bronchioles

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

What does the glandular tissue in the loose tissue do?

A

Produces mucus

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

What do goblet cells and ciliated epithelium work together to do?

A
  • Goblet cells in the epithelium release mucus which traps pathogens
  • The cilia then move the mucus up to the top of the airway where it is swallowed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What can smooth muscle do?

A

Contract and restrict the airways. Makes the lumen smaller which restricts the flow of air to the alveoli.

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

Why does smooth muscle constrict the airways?

A

Can be important if there are harmful substances in the air. Not a voluntary response and may be due to an allergic reaction.

24
Q

How does smooth muscle return to its original shape?

A

It cannot do it by itself, but is elongated by elastic fibres.
When the smooth muscle contracts, it deforms the elastic fibres, but as the muscle relaxes, the elastic fibres recoil to their original shape and size, which causes the airway to dilate.

25
Q

Why do the alveolus walls contain elastic fibres?

A

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

26
Q

Breathing rate definition:

A

Number of breaths per minute

27
Q

Oxygen uptake definition:

A

The volume of oxygen absorbed by the lungs in one minute

28
Q

Tidal volume definition:

A

The volume of air inhaled or exhaled in one breath, usually measured at rest

29
Q

Vital capacity definition:

A

The greatest volume of air that can be expelled from the lungs after taking the deepest breath possible

30
Q

How does a spirometer work?

A
  • During inspiration, the lid moves down and during expiration the lid moves up. These movements are recorded on a data logger
  • The air that is exhaled will contain carbon dioxide. This passes through a chamber of soda lime, which absorbs the carbon dioxide.
31
Q

Why is a chamber of soda lime essential in a spirometer?

A

It absorbs the carbon dioxide breathed out. This mean that oxygen consumption can be measured

32
Q

Buccal cavity definition:

A

The mouth (of a fish)

33
Q

Counter current flow definition:

A

Where two fluids flow in opposite directions

34
Q

Filaments definition:

A

Slender branches of tissue that make up the gill. Often called primary lamellae

35
Q

Lamellae definition:

A

Sometimes called secondary lamellae or gill plates. Folds of the filament to increase surface area

36
Q

Operculum definition:

A

Bony flap that covers and protects the gills

37
Q

Spiracle definition:

A

An external opening or pore that allows air in or out of the trachae

38
Q

Tracheal fluid definition:

A

A fluid found at the ends of the tracheoles in the tracheal system

39
Q

Tracheal system definition:

A

A system of air filled tubes in insects

40
Q

How many pairs of gills do most bony fish have?

A

5

41
Q

What are the gills in bony fish covered by?

A

A bony plate called the operculum. This protects the gills

42
Q

What does each gill consist of?

A

Two rows of gill filaments (primary lamellae) attached to a bony arch

43
Q

How is there a large surface area at the gills?

A

The gill filaments that make up the gill are very thin and their surface is folded into secondary lamellae (gill plates)

44
Q

Where does gas exchange happen in fish?

A

Close to the surface of the secondary lamellae. Blood capillaries carry deoxygenated blood here

45
Q

Where does blood flow in bony fish?

A
  • Along the gill arch and out along the filaments to the secondary lamellae
  • Then through the capillaries in the opposite direction to the water flowing over the lamellae
  • This creates a counter current flow that absorbs the maximum amount of water from the oxygen
46
Q

How can bony fish keep water flowing over the gills?

A

By using the buccal-opercular pump

47
Q

How does the bucal-opercular pump work?

A
  • The buccal cavity can change volume
  • The floor of the mouth moves down, drawing water into the buccal cavity
  • The mouth closes which raises the floor and pushes water through the gills
  • Movements of the operculum are coordinated with movements of the buccal cavity
  • As water is pushed from the buccal cavity, the operculum moves outwards
48
Q

Why does the operculum move outwards when water is pushed from the buccal cavity?

A

It reduces the pressure in the opercular cavity (space under the operculum) which helps water to move through the gills

49
Q

What kind of circulatory system do insects have?

A

Open circulatory system which acts as both blood and tissue fluid. Air is supplied directly to all respiring tissues. Circulation is slow and can be affected by body movements

50
Q

How does an insects open circulatory system work?

A
  • Air enters the system via a spiracle (pore) in each segment
  • Air is transported into the body through a series of tracheae which divide into smaller and smaller tubes called tracheoles
  • The ends of tracheoles are open and filled with tracheal fluid
51
Q

Where does gas exchange happen in insects?

A

Between the air in the tracheole and in the tracheal fluid. Some gas exchange can also occur across thin walls of tracheoles.

52
Q

What happens when tissues in an insect are active?

A

The tracheal fluid can be withdrawn into the body fluid. This increases the surface area of the tracheole wall exposed to air, so more oxygen can be absorbed when the insect is active

53
Q

How does some insects having sections of the tracheal system expanded and having flexible walls increase ventilation?

A

These sections act as air sacs which can be squeezed by flight muscles. Repetitive expansion and contraction of these air sacs can ventilate the tracheal system

54
Q

How does movement of the wings altering the volume of the thorax in some insects increase ventilation?

A
  • As the thorax volume decreases, air in the tracheal system is put under pressure and forced out
  • When the thorax volume increases, pressure drops and air is forced in
55
Q

How have locusts developed ventilation?

A
  • They can alter the volume of their abdomen through specialised breathing movements which are coordinated with opening and closing valves in the spiracles
  • As the abdomen expands, spiracles at the front of the body open and let air in
  • As the abdomen reduces in volume, the spiracles at the rear end of the body open and air can leave the body

AS OCR Biology (12 decks)

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