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A Level: Biology > Exchange Surfaces > Flashcards

Exchange Surfaces Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Define tissue

A

A collection of similar cells that are specialised to work together for a particular function

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2
Q

Why must large active organisms have a specialised has exchange surface

A 
Higher demand for oxygen 
Greater need to remove CO2
Smaller SA:Vol 
Diffusion distance too great to just use surface area as diffusion would take too long
=> need for specialised exchange surface
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3
Q

Explain why small inactive organisms do not need a specialised has exchange surface

A

Lower demand for O2 and CO2 to be removed
Have a large SA:Vol
Diffusion distance short enough to use only SA- diffusion happens quickly

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4
Q

Name 6 factor which affect the rate of diffusion

A 
Temperature 
Concentration gradient 
Stirring movement
Surface area
Diffusion distance
Size of molecule
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5
Q

What is the formula for rate of diffusion

A

Rate of diffusion= (area of diffusion surface x difference in concentration)/ thickness of membrane

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6
Q

Describe the structure of the alveoli and how it helps it to carry out its function

A
  • squamous epithelium- one cell thick- short diffusion distance for CO2 and O2
  • good blood supply as capillary runs close to alveoli- maintaining high concentration gradient
  • elastic fibres so can stretch and recoil, this helps prevent bursting
  • small size of alveoli: large SA:vol
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7
Q

Describe the movement of oxygen from trachea to the blood

A

1)Oxygen moves through the trachea> bronchi> bronchioles> alveoli
2) dissolves in thin liquid layer into solution
3)

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8
Q

What is the function of elastic fibres

A

Can stretch and recoil
This prevents bursting
Recoiling helps expel air and maintain a conc gradient

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9
Q

What type of specialised cell is the capillary made up of

A

Squamous endothelium

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10
Q

What is the function of c shaped cartilage in the trachea

A

Prevent the airway from closing

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11
Q

In the trachea there are elastic fibres and what other type of fibres

A

Smooth muscle fibres

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12
Q

What is the job of smooth muscle fibres

A

Contract to reduce diameter of trachea

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13
Q

Explain the job of goblet cells in the trachea

A

Goblet cells release mucus, this traps particles (pollen/bacteria), then the ciliates epithelium cells waft (using atp) the mucus to the top of the trachea

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14
Q

Describe the structure of ciliates epithelial tissue

A

Columnar cells, they have cilia which can beat rhythmically to prevent unwanted particles from entering lungs

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15
Q

What does the smooth muscles fibres in the bronchiole do

A

Contract to reduce diameter of bronchiole

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16
Q

Is there ciliates epithelial cells in the bronchiole

A

Yes and goblet cells

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17
Q

Explain what happens during an asthma attack

A

Mast cells in the lungs bind to pathogen
They then release histamines into the area
These histamines bind to receptors
Triggering the muscle to contract and capillary walls to be more leaky - more tissue fluid

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18
Q

What is the diaphragm

A

A broad, domed sheet of muscle which forms the floor of the thorax

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19
Q

What do the internal intercostal muscle do

A

When u exhale forcibly using energy they contract pulling the ribs down hard and fast

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20
Q

What is the job of the rib cage

A

Provides a semi-rigid case within which pressure can be lowered with respect to the air outside

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21
Q

What do the external intercostal muscle do

A

When they contract, it moves the rib cage up and out, when relax it moves rib cage down and in

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22
Q

Describe the process of inhalation

A 
External intercostal muscle contract
Rib cage moves up and out 
Diaphragm contracts and moves down
Thorax volume increased
Pressure in thorax decreases
Air moves in
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23
Q

What happens during exhalation

A 
External IC muscles relax
Rib cage moves down and in 
Diaphragm relaxes and moves up
Thorax volume decreases
Thorax pressure increases
Air moves out
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24
Q

What is surfactant

A

A lipoprotein that stabilises the alveoli preventing collapse

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25
Q

What is ventilation rate

A

The number of breaths per minute

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26
Q

What’s the formula for tidal volume

A

The volume of air inhaled or exhaled in one breath during steady regular breathing

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27
Q

Formula for pulmonary ventilation

A

Ventilation rate x tidal volume

28
Q

What is vital capacity

A

The maximum volume of air inhaled or exhaled in one breath

29
Q

What is a spirometer used to measure

A

Tidal volume

30
Q

How do u use a spirometer

A

A nose clip is fitted so that all air comes from the chamber
They breathe normally through mouth
The trace is measured for height and amplitude

31
Q

In a spirometer what removed CO2

A

Soda lime / sodium hydroxide

32
Q

Name the system insects use to exchange gas

A

The tracheal system

33
Q

Where are spiracles found

A

Along the thorax and abdomen

34
Q

How does air enter and leave the system

A

Via spiracles

35
Q

What opens and closes these spiracles

A

Sphincters

36
Q

What do tracheae do

A

Carry air into the insect body

37
Q

How are tracheae kept open

A

By circular bands of chitin which is impermeable to gases

38
Q

What to tracheae go into

A

Tracheoles (these are so small that they run between individual cells)

39
Q

There are vast numbers of tracheoles, what does this mean

A

A very large surface area for exchanging gases

40
Q

How does oxygen diffuse into cells of insects

A

It dissolved into the moisture on the walls of tracheoles and into surrounding cells

41
Q

What is there towards the end of the tracheoles

A

Tracheal fluid

42
Q

What does tracheal fluid do

A

Limit the penetration of air for diffusion

43
Q

What happens when oxygen builds up when flying for example

A

Lactic acidosis builds up in the tissue
Water then moves by osmosis from tracheoles into tissues
Exposing more surface for gaseous exchange

44
Q

How is the tracheal system ventilated

A

Mechanically, aid is actively pumped into the system by muscular pumping movements of the thorax/ abdomen this changes the volume and pressure in the tracheae and tracheoles

Air is drawn in and forced out when pressure changes

45
Q

What is the purpose of collapsible enlarged tracheae (air sacs)

A

They act as reservoirs to increase the amount of air that is moved through the system

Can inflate and deflate

46
Q

What are the three states of a discontinuous gaseous exchange cycle

A

Spiracles are:
Open
Closed
Fluttering

47
Q

Explain what happens when spiracles in DCG are:
Closed
Fluttering
Open

A

Closed- no gas moves in or out, oxygen diffuses into cells, CO2 is held in body fluids
Fluttering- spiracles open and close rapidly, moving fresh air into traceable, minimises water lost
Open- CO2 builds up in body fluids

48
Q

Describe the SA:Vol in fish

A

Small sa:volume

49
Q

Name three features of gills that make them good at their job

A

Very thin= short diffusion distance
Large SA= increase rate of diffusion
Good blood supply= maintain steep conc gradient

50
Q

Describe the movement of water through the mouth

A

Enters the mouth (buccal cavity)
Passes over gills
Leaves via opercular opening

51
Q

What covers the gills

A

Operculum

52
Q

How does the fish ventilate the gills

A

By alternatively opening and closing buccal cavity

53
Q

Explain what happens when the mouth is open in a fish

A

-mouth opened/ floor of buccal cavity drops decreasing pressure
Volume of buccal cavity increases
-water moves in (opercular valve is shut)
-opercular cavity (where gills is) expands which lowers pressure
-floor of buccal cavity rises, increasing pressure
-water moves from buccal cavity over the gills due to pressure difference

54
Q

What happens when mouth is closed in a fish

A
  • Mouth closed and operculum opens
  • sides of opercular cavity move inwards
  • increase of pressure in opercular cavity forces water over the gills and out the operculum
  • floor of buccal cavity moves up maintaining the flow of water over gills
55
Q

Describe the structure of gills

A

Each Gill is made of four bony gill arches
These are lined with hundreds of gill filaments that are very thin and flat
The gill filaments occur in large stacks called gill plates

56
Q

What is a gill plate

A

A large stack of gill filaments

57
Q

How many bony gill arches in a gill

A

Four

58
Q

What are lamellae

A

These are on the filament and increase SA more

59
Q

The bony gill arch contains two vessels

Describe

A

Efferent vessel/ takes blood out of the system

Afferent vessel/ brings blood into the system

60
Q

The gill filaments overlap with the neighbouring gill arch filaments providing resistance to water, why is this important

A

passage of water slows

Means there is more time for gaseous exchange

61
Q

What occurs in a counter current system

A

Water moves over the gills and blood in the gill filament flows in the opposite direction

62
Q

What are the advantages of a counter current system

A

Constant diffusion of O2 as it does not reach a dynamic equilibrium as there is a constant concentration gradient

63
Q

What is a concurrent system

What is a disadvantage of this

A

Where the blood and water moving over gills flows in the same direction

Equilibrium is quickly reached and there is no further diffusion

64
Q

What type of system does a bony fish have

A

Counter current

65
Q

What type of system does a cartilage fish have

A

Concurrent/ parallel system

A Level: Biology (18 decks)

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