Brainscape's Knowledge GenomeTM

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


See full index

Biology OCR A A level > Exchange Surfaces and Breathing > Flashcards

Exchange Surfaces and Breathing Flashcards

1
Q

What are the two main reasons as to why single celled organisms can rely on diffusion alone?

A

Metabolic demands are low

Surface area to volume ratio is high

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

What are the 4 key features of a good exchange surface?

A

Increased Surface Area
Thin Layers
Good Blood Supply
Ventilation to maintain diffusion gradient

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

What are the benefits of an increased surface area? Give examples of places with this.

A

Provides are for exchange and overcomes the limitations of SA:V ratio
Eg. Root Hair Cells and Villi

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

What are the benefits of thin layers? Give examples of places with this.

A

Distances substances have to diffuse is short, making process faster and more efficient
Eg. Alveoli and Villi

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

What are the benefits of a good blood supply ? Give examples of places with this.

A

Steeper the concentration gradient, faster diffusion takes place.
Eg. Alveoli, Gills and Villi

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

What are the benefits of good ventilation? Give examples of places with this.

A

For gases, helps maintain concentration gradients and make process more efficient
Eg. Alveoli and Gills

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

What has the Mammalian Gaseous Exchange system had to evolve to do?

A

Complex systems that allow for efficient gaseous exchange but minimise water loss

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

What are three key features of the nasal cavity and what do they do?

A

Large surface area with good blood supply- warms air to body temperature
Hairy lining- which secretes mucus to trap dust and bacteria protecting lungs from irritation
Moist surfaces- increase humidity preventing evaporation

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

What is the trachea?

A

Main airway carrying clean warm, moist air from the nose down the chest

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

What is the structure of the trachea?

A

Wide tube supported by incomplete rings of strong, flexible cartilage which stop the tube from collapsing

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

Why are tracheal rings incomplete?

A

To allow food to easily move down the oesophagus because that is behind the trachea

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

What is the trachea lined with?

A

Ciliated epithelium and goblet cells

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

What is the role of goblet cells?

A

To secrete mucus onto the lining of the trachea, to trap dust and microorganisms that have escaped the nose lining.

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

What prevents mucus entering the lungs? How?

A

Cilia beat mucus and microorganisms away from lungs, mostly into the throat where it is digested

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

What is the effect of cigarette smoke on the trachea?

A

Stops cilia beating

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

What are the bronchi?

A

Supporting rings of cartilage that are smaller than the trachea and branch into each lung

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

What is the structure of bronchioles?

A

No cartilage rings

Smooth muscle

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

How does smooth muscle link to role of bronchioles?

A

Smooth muscles contract- bronchioles constrict
Smooth muscle relaxes- bronchioles dilate
Affects how much oxygen reaches lungs

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

Can gaseous exchange occur in bronchioles?

A

Yes, as the are lined with a layer of flattened epithelium

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

What is the structure of alveoli?

A

Tiny air sacs made from thin, flattened epithelial cells

Contains some collagen and elastic fibres

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

What is elastic recoil?

A

Elastic tissues stretching to allow alveoli to draw in maximum amount of air, then returning to resting size to help squeeze air out.

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

How are alveoli adapted?

A

Large surface area
Thin layers- one epithelial cell thick cell walls
Good blood supply
Good ventilation - from breathing

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

What is the role of ‘lung surfactant’?

A

Allows alveoli to remain inflated

24
Q

What causes ventilation to occur?

A

Pressure changes in the thorax

25
Q

What is the pleural cavity filled with? Why?

A

Thin layer of lubricating fluid so the membranes slide easily over each other

26
Q

Explain what happens during inspiration

A

Diaphragm contracts- flattening and lowering
External intercostal muscles contract
Ribs move upwards and outwards
Volume of thorax increase= pressure in thorax decreases
Lower than atmospheric pressure so air drawn in

27
Q

Explain what happens during passive expiration

A

Diaphragm relaxes into resting dome shape
External intercostal muscles relax
Ribs move downwards and inwards
Alveoli elastic fibres return to normal length
Decreased volume of thorax
Pressure inside greater than outside, air forced out

28
Q

What happens during forced expiration?

A

Requires energy
Internal intercostal muscles contract
Ribs pulled down hard and fast
Abdominal muscles contract forcing diaphragm up to increase pressure rapidly

29
Q

What does a peak flow meter measure?

A

The rate at which air can be expelled from the lungs

30
Q

What does a vitalograph measure?

A

Amount of air breathed out and how quickly (the forced expiratory volume in 1 second)

31
Q

What does a spirometer measure?

A

Different aspects of long volume or breathing patterns

32
Q

Define ‘tidal volume’

A

The volume of air that moves into and out of the lungs with each resting breath

33
Q

Define ‘vital capacity’

A

Volume of air that can be exhaled when the deepest possible intake of breath is followed by the longest possible exhalation

34
Q

Define ‘inspiratory reserve volume’

A

The maximum volume of air you can breath in over a normal exhalation

35
Q

Define ‘expiratory reserve volume’

A

The maximum volume of air you can force out of your lungs above your tidal volume of air you breathe out

36
Q

Define ‘residual volume’

A

The volume of air that is left in your lungs when you have exhaled as hard as possible

37
Q

Define ‘total lung capacity’

A

The sum of the vital capacity and residual volume

38
Q

What is the breathing rate?

A

The number of breaths taken per minute

39
Q

What is the ventilation rate?

A

The total volume of air inhaled in one minute

40
Q

Give the equation for ventilation rate

A

Ventilation Rate= breathing rate x tidal volume

41
Q

Explain how a spirometer works

A

Nose clip
Subject breaths in and out until oxygen is used up
Trace drawn on revolving drum
Cannister of soda lime removes carbon dioxide

42
Q

What are spiracles?

A

Small openings in the thorax of an insects body that allows for the movement in and out of oxygen and carbon dioxide

43
Q

How do insects minimise water loss during gaseous exchange?

A

Spiracle sphincters remain shut as much as possible

44
Q

What is the structure of trachea in an insect?

A

Tubes lined with chitin which keep them open if bent or pressed

45
Q

Can gaseous exchange occur in the trachea of an insect?

A

Very little because chitin is impermeable

46
Q

What is the structure of tracheoles?

A

Single, elongated cells which have no chitin lining which pass throughout the tissues of an insect

47
Q

How does oxygen move through an insect normally?

A

Through the trachea into the tracheoles where oxygen dissolves into the moisture on the cell walls and then diffuses into cells

48
Q

How is tracheal fluid adapted to help the insect?

A

Tracheal fluid normally limits the penetration of air
Lactic acid builds up when oxygen demands are high
This lowers water potential of tracheal fluid so water moves out via osmosis.
Exposes more surface area for gaseous exchange

49
Q

What are two alternative methods that insects have to gain more oxygen?

A

Mechanical ventilation of the tracheal system

Collapsible enlarged tracheae or air sacs

50
Q

What adaptations to gill lamellae have? What occurs there?

A

Main site of gaseous exchange in a fish

Rich blood supply and large surface area= efficient exchange

51
Q

What is the structure of gill filaments and how does this help gaseous exchange occur?

A

Large stacks of gill filaments-gill plates

Flow of water keeps them apart showing large surface area for gaseous exchange

52
Q

What is the role of a gill arch?

A

Supports structure of gills

53
Q

What is the operculum?

A

The flap that covers gills

54
Q

What is ram ventilation?

A

Relying on continual movement to ventilate the gills

55
Q

Explain process of ventilation in a bony fish

A 
Floor of buccal cavity drops
Volume increases
Pressure decreases
Water enters
Mouth closes
Operculum squeezes inwards
Buccal cavity floor moves upwards
Volume decreases
Pressure increases
Water forced out over gills
56
Q

What are the 3 major adaptations for successful gaseous exchange in bony fish?

A

Large Surface Area
Adjacent gill filaments overlap increasing resistance so more time for exchange to occur
Counter current blood flow system-allows steep concentration gradient to be maintained

57
Q

Compare blood flow systems in cartilaginous and bony fish

A

Cartilaginous- parallel system, 50% oxygen extracted

Bony- counter current, 80% oxygen extracted

Biology OCR A A level (17 decks)

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