Lesson 1: Gas Exchange Flashcards

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1
Q

Why do larger multi-cellular organisms need exchange systems?

A
  • small surface area to volume ratio
  • cells in the centre of the organisms would not receive anything using only diffusion.
  • higher metabolic rate
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2
Q

what are five characteristics of specialised exchange surfaces in animals?

A
  • concentration gradient
  • Large Surface Area
  • Thin layers
  • Moist surface
  • Permeability
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3
Q

How is having a large surface area an adaptation for efficient gas exchange?

A

a large area that gas exchange can occur over.

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4
Q

How is having thin layers an adaptation for efficient gas exchange?

A

short diffusion path

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5
Q

How is having a good blood supply an adaptation for efficient gas exchange?

A

maintain a large diffusion gradient, constant diffusion

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6
Q

How is having a moist surface an adaptation for efficient gas exchange?

A

dissolves gas

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6
Q

How is ventilation an adaptation for efficient gas exchange?

A

maintains diffusion gradient

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7
Q

How is permeability an adaptation for efficient gas exchange?

A

pores and openings

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8
Q

What adaptations do animals have to maintain a steep concentration gradient at exchange surfaces?

A
  • A dense network of blood vessels
  • Continuous blood flow
  • Ventilation
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9
Q

describe the nasal cavity

A
  • large SA & good blood supply = warms air to body temperature
  • hairy lining = traps bacteria and dust
  • moist = increases humidity and reduces evaporation
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10
Q
A
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11
Q

describe the trachea

A
  • c shape cartilage rings = prevents collapse and allows food down oesophagus
  • mucus membrane lining produces mucus to trap dust and bacteria
  • smooth muscle to regulate air flow
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12
Q

describe the bronchioles

A
  • small diameter slows air flow = more time for gas exchange in the alveoli.
  • high degree of branching also ensures that air is distributed throughout the lungs.
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13
Q

describe alveoli

A
  • made up of collagen, elastic fibres and flattened epithelial cells.
  • elastic fibers recoil removing air from alveoli
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14
Q

describe surfactant

A
  • dissolves gasses
  • reduces surface tension, preventing collapse
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15
Q

What are the adaptations of alveolis for efficient gas exchange?

A
  • Large surface area: numerous + folded
  • Short diffusion distance: one cell thin
  • Large concentration gradient: surround by an extensive network of capillaries and regular ventilation
16
Q

What is the difference between type 1 and 2 pneumocytes in structure and coverage %?

A

type 1:
* covers 95% of alveoli SA
* thin + flat cells
type 2:
- cuboidal cells
- 5%

17
Q

What is the difference between type 1 and 2 pneumocytes in function?

A

type 1: gas exchange
type 2: produces surfactant + differentiate into type 1 (when damaged).

18
Q

summarise ‘inspiration’

A
  • Diaphragm contract – Moves Down
  • External Intercostal Muscles contract – move up and out
  • Thoracic Volume – Increases
  • Thoracic Pressure – Decreases
  • Air Flow – In to lungs (to equalise the pressure difference)
19
Q

```

summarise ‘expiration’

A
  • Diaphragm – Moves up
  • External Intercostal Muscles – move down and in
  • Thoracic Volume – decreases
  • Thoracic Pressure – increases
  • Air Flow – out the lungs (to equalise the pressure difference)
20
Q

what are external intercostal muscles used for?

A

forced expiration

21
Q

what does tidal volume mean?

A

the volume of air in each breath

22
Q

what does vital capacity mean?

A

The maximum volume of air that can be breathed in and out

23
Q

what does breathing rate mean?

A

The number of breaths per minute

24
Q

what does oxygen uptake mean?

A

The rate at which a person uses up oxygen (dm3 min-1)

25
Q

What device is used to measure lung volume?

A

spirometer

26
Q

What happens to lung volume after exercise?

A

tidal volume and **rate of breathing **increases due to taking in more oxygen and removing more carbon dioxide.

27
Q

What factors can affect your lung capacity?

A
  • age
  • body composition
  • biological sex
  • respiratory disease
  • level of physical activity
28
Q

what is haemoglobin?

A

protein molecule found within red blood cells

29
Q

what is the function of haemoglobin?

A

carries oxygen

30
Q

what can haemoglobin bind to?

A

oxygen and carbon dioxide

31
Q

what is the structure of haemoglobin?

A
  • quaternary structure
  • 4 polypeptides
  • each polypeptide has a haem group
  • each haem group has an iron molecule
32
Q

what is saturated haemoglobin?

A

haemoglobin bounded to oxygen molecule(s)

33
Q

What is cooperative binding of oxygen to haemoglobin?

A

as oxygen binds to haemoglobin, the affinity for oxygen increases due to shape change making it easier for other oxygen molecules to bind

34
Q

how many oxygens can a haemoglobin bind to?

A

8

35
Q

what does affinity mean?

A

attraction (for)

36
Q

How does foetal haemoglobin differ from adult?

A

higher affinity for oxygen

37
Q

what happens when a carbon dioxide attaches to a haemoglobin?

A

oxygen is released and affinity decreases