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A Level Biology - OCR Biology A > 3.1.1 Exchange surfaces > Flashcards

3.1.1 Exchange surfaces Flashcards

1
Q

Name two substances that are absorbed across an exchange surface.

A

Oxygen and glucose

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2
Q

Do multicellular organisms have a large or small surface area to volume ratio?

A

Small

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3
Q

What are three adaptations of the alveoli for efficient gas exchange?

A
  • Walls are one cell thick, to create short diffusion distance
  • Good blood supply, which maintains a steep concentration gradient
  • Many alveoli which are very small, creating a large surface area
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4
Q

Name the process by which oxygen passes from the alveolus in the lungs and into the blood.

A

(Simple) diffusion

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5
Q

Name the flap under which you find the gills.

A

Operculum

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6
Q

What are three adaptations in the gills for efficient gas exchange?

A
  • Many folds called lamellae, creating a large surface area
  • Walls of gill filaments are one cell thick, creating a short diffusion distance
  • Counter-current flow between water and blood in capillaries creates a steep concentration gradient
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7
Q

What are four common features of an efficient exchange surface?

A

Large surface area
Short diffusion distance
Good blood supply
Ventilation mechanism

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8
Q

What is the purpose of cartilage in the trachea?

A

Keeps airways open

Prevents trachea from collapsing when you breathe in and pressure drops

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9
Q

In which tissues in the mammalian gas exchange system is the ciliated epithelium found?

A
  • Trachea
  • Bronchi
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10
Q

What is the purpose of mucus in the trachea and bronchi?

A

Traps pathogens

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11
Q

What is the purpose of cilia in the trachea and bronchi?

A

Wafts mucus up and out of the airway

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12
Q

In which tissues in the mammalian gas exchange system is smooth muscle found?

A
  • Bronchi
  • Bronchioles
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13
Q

In which tissues in the mammalian gas exchange system are elastic tissues found?

A

In ALL lung tissues

(Trachea, bronchi, bronchioles, alveoli)

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14
Q

What is the function of smooth muscle in the bronchi and bronchioles?

A

Dilates to increase air flow

Constricts to reduce air flow

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15
Q

What is the purpose of elastic fibres in the mammalian gas exchange system?

A

Fibres recoli to help push air out when exhaling

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16
Q

What shape are the rings of cartilage in the trachea?

A

C-shaped rings

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17
Q

What happens to the internal and external intercostal muscles during inspiration (inhalation)?

A
  • External intercostal muscles contract
  • Internal intercostal muscles relax
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18
Q

What happens to the internal and external intercostal muscles during expiration (exhalation)?

A
  • External intercostal muscles relax
  • Internal intercostal muscles relax during passive expiration (but contact during forced expiration)
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19
Q

Describe what happens inside the chest cavity during inspiration.
Talk about the changes in muscles, volume and pressure.

A

Diaphragm contracts and pulls
down
External intercostal muscles
contract
Ribcage moves upwards and
outwards
Volume inside chest cavity increases
Pressure inside chest cavity decreases
There is more pressure outside the lungs
Air particles are drawn in to balance the pressure difference

20
Q

Is inspiration an active or passive process?

A

Active (because it requires energy)

21
Q

Describe what happens inside the chest cavity during expiration.
Talk about the changes in muscles, volume and pressure.

A

Diaphragm relaxes
External intercostal muscles relax
Ribcage moves downwards and inwards
Volume in thorax (chest cavity) decreases
Pressure inside thorax increases
Air is forced out of the lungs

22
Q

What is the role of elastic fibres in expiration?

A

Elastic fibres are stretched during inspiration
During expiration, elastic fibres recoil
This helps to reduce the volume inside the thorax
Air is therefore expelled

23
Q

Is expiration an active or passive process?

A

Passive (does NOT require energy)

24
Q

When the rubber sheet of a bell jar is pulled down the balloons expand.
Explain why the balloons expand.

A

volume inside of jar increases

pressure inside jar / balloons decreases

to below pressure in atmosphere

(therefore) air moves / is pushed into / is forced into balloons / glass tube

25
Q

Name this piece of equipment.

A

Spirometer

26
Q

Name four readings that you can obtain using a spirometer.

A

Tidal volume
Vital capacity
Breathing rate
Oxygen uptake

27
Q

Describe how a ‘spirometer trace’ is formed.

A

Person breathes through tube connected to oxygen chamber

Lid of oxygen chamber moves up and down

Movements are recorded by the pen

28
Q

What is the purpose of soda lime in a spirometer?

A

It absorbs carbon dioxide from a person’s exhaled air

29
Q

Why does the volume of gas in the oxygen chamber decrease over time as a person uses a spirometer?

A

The air that is exhaled is a mixture of oxygen and carbon dioxide

Carbon dioxide is absorbed by the soda lime

There is only oxygen in the chamber which the patient inhales from

As oxygen is inhaled and used up in respiration, the total volume decreases

30
Q

What is ‘breathing rate’?

A

The number of breaths taken per minute

31
Q

What is ‘tidal volume’?

A

The volume of air that is breathed in or out during normal breathing (at rest).

32
Q

What is ‘vital capacity’?

A

The maximum volume of air that can be breathed in or out in one breath.

33
Q

What is ‘oxygen uptake’?

A

The volume of oxygen used up in a given time.

34
Q

Which letter shows the residual volume?

A

H

35
Q

What is ‘residual volume’?

A

The amount of air left in the lungs after fully exhaling.

36
Q

What is ‘total lung capacity’?

A

The maximum amount of air that the lungs can hold after taking the deepest breath possible.

37
Q

Which letter shows the total lung capacity?

A

D

38
Q

Which letter shows the tidal volume?

A

F

39
Q

Which letter shows the vital capacity?

A

C

40
Q

Describe what happens during inspiration in bony fish.
Include information about changes in pressure and volume.

A

Fish opens mouth
Lower the floor of the buccal cavity
Increased volume inside buccal cavity
Decreased pressure inside buccal cavity
Pressure is higher outside the mouth
Water flows into buccal cavity

41
Q

Describe what happens during expiration in bony fish.
Include information about changes in pressure and volume.

A

Fish closes mouth
Raises the floor of the buccal cavity
Decreased volume inside buccal cavity
Increased pressure inside buccal cavity
Pressure is higher inside the mouth
Operculum is forced to open
Water exits through the operculum

42
Q

Name the structure that increases the surface area in fish gills.

A

Lamellae

43
Q

Name the pore found in the exoskeleton of an insect.

A

Spiracle

44
Q

What are three adaptations of the tracheal system in insects?

A

Tracheoles have thin walls
(up to one cell thick)
Creates a short diffusion distance

Tracheoles contain fluid
Allows oxygen to dissolve for faster diffusion

Trachea are supported by circles of chitin
Prevents trachea from collapsing

45
Q

What is the purpose of valves in the insects’ trachea?

A

Prevents water loss

A Level Biology - OCR Biology A (13 decks)

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