Specialised Exchange Surfaces Flashcards

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1
Q

What are the characteristics of a specialised exchange surface?

A
  • Large surface area
  • Thin layers
  • Good blood supply
  • Ventilation
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2
Q

Why is ventilation important?

A

1) Maintains a concentration gradient

2) More efficient process

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3
Q

Why is a good blood supply important?

A

Ensures substances are constantly being removed and delivered to the exchange surface which maintains a steep concentration gradient for diffusion.

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4
Q

What are the features of the nasal cavity?

A
  • Large SA
  • Good blood supply
  • Moist surfaces
  • Hairy lining
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5
Q

Why does the nasal cavity need a good blood supply?

A

Warms the air to body temperature

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6
Q

Why does the nasal cavity need moist surfaces?

A

Increase humidity of the incoming air, reducing evaporation from exchange surfaces.

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7
Q

Why does the nasal cavity need a hairy lining?

A

Secretes mucus to trap dust and bacteria, protecting the lug tissue from infection.

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8
Q

What is the pathway of air into the body?

A

Nasal cavity, trachea, bronchus, bronchioles, alveoli

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9
Q

What is the structure of the trachea?

A

Wide tube supported by incomplete rings of strong, flexible cartilage, which stops it from collapsing.

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10
Q

Why are the rings in the trachea incomplete?

A

So food can move easily down the oesophagus behind the trachea.

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11
Q

What lines the trachea?

A

Ciliated epithelium with goblet cells between and below epithelia cells.

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12
Q

What is the purpose of goblet cells in the trachea?

A

Secrete mucus to trap dust and microorganisms.

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13
Q

How does the structure of the bronchus differ to that of the trachea?

A

It is smaller but still has the rings of cartilage.

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14
Q

What is the structure of bronchioles?

A

No cartilage.
Walls contain smooth muscle, so can control the amount of air reaching the lungs.
Lined with a thin layer of flattened epithelium.

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15
Q

What tissue allows the alveoli to stretch and recoil?

A

Elastic

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16
Q

What is it called when alveoli return to their resting size to squeeze air out?

A

Elastin recoil

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17
Q

What are the adaptations of the alveoli?

A
  • Large SA
  • Thin layers
  • Good blood supply
  • Good ventilation
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18
Q

What is the inner surface of the alveoli covered in?

A

A thin layer of a solution, water, salts and lung surfactant.

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19
Q

What is the role of the lung surfactant in the alveoli?

A

Makes it possible for alveoli to remain inflated.

20
Q

What is ventilation?

A

The movement of air in and out of the lungs as a result of pressure changes in the thorax.

21
Q

Inspiration

A

1) External intercostal muscles contract. Internal intercostal muscles relax.
2) This forces the ribcage up and out.
3) The diaphragm contracts.
4) Forcing it to flatten.
5) These two movements cause the volume of the thorax to increase.
6) So the pressure decreases.
7) Pressure is now lower than atmospheric pressure, so air is drawn in.

22
Q

Expiration

A

1) Internal intercostal muscles contract. External intercostal muscles relax.
2) This forces the ribcage down and in.
3) The diaphragm relaxes.
4) Forcing it to bulge upwards.
5) These two movements cause the volume of the thorax to decrease.
6) So the pressure increases.
7) Pressure is now higher than atmospheric pressure, so air is forced out.

23
Q

What do people with asthma have?

A

Airways that are sensitive to everyday triggers such as pollen, stress and house dust mites.

24
Q

What are the two main ways of treating asthma?

A

Relievers

Preventers

25
Q

What are relievers?

A

Give immediate relief from symptoms. Attach to active sites on the surface membranes of smooth muscle in the bronchioles, making them relax.

26
Q

What are preventers?

A

Steroids which are taken daily to reduce the sensitivity of the lining of the airways.

27
Q

How can you measure the volume of air drawn in and out of the lungs?

A

Peak flow meter.

Spirometer.

28
Q

What is a peak flow meter?

A

Measures rate at which air can be expelled from the lungs.

29
Q

What is a spirometer?

A

Investigates breathing patterns.

30
Q

Tidal Volume

A

Volume of air that moves into and out of the lungs with each resting breath.

31
Q

Vital Capacity

A

Volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible intake of breath.

32
Q

Expiratory Reserve Volume

A

Extra amount of air that can be forced out of your lungs over and above the normal tidal volume of air you breathe out.

33
Q

Inspiratory Reserve Volume

A

The maximum volume of air you can breath in over and above a normal inhalation.

34
Q

Residual Volume

A

Volume of air that is left in your lungs when you have exhaled as hard as possible.

35
Q

What cannot be measured directly?

A

Residual volume

36
Q

Total Lung Capacity

A

The sum of the Vital Capacity and the residual volume

37
Q

What is the breathing rate?

A

Number of breaths taken per minute.

38
Q

How do you calculate Ventilation Rate?

A

Tidal volume X Breathing rate

39
Q

What are the adaptations of gills to ensure effective gaseous exchange?

A
  • Rich blood supply
  • Thin layers
  • Tips of gill filaments overlap
  • Water moving over the gills and the blood in the gill filaments flow in different directions.
40
Q

How does overlap tips of gill filaments give effective exchange?

A

Increases resistance to flow of water and slows down the movement of the water. So more time for gaseous exchange to take place.

41
Q

How does the water and blood flowing in different directions allow for gaseous exchange?

A

Sets up a countercurrent exchange system.

A concentration gradient is sent up all along the gill.

42
Q

How do fish keep a current of water flowing over their gills?

A

Open their mouth and operculum.

43
Q

What do primitive cartilaginous fish rely on?

A

Continual movement to ventilate the gills.

44
Q

What is it called when fish rely on continual movement?

A

Ram ventilation

45
Q

What is the system of bony fish for the ventilation of the gills?

A

1) Mouth opens and floor of buccal cavity is lowered.
2) This increases volume of the buccal cavity.
3) Pressure in the cavity drops and water moves into the buccal cavity.
4) At the same time, the opercular valve is shut and the opercular cavity containing the gills expands.
5) This lowers the pressure in the opercular cavity containing the gills.
6) The floor of the buccal cavity starts to move up, increasing the pressure so water moves from the buccal cavity over the gills.

46
Q

What are the differences of water to air?

A

Water is denser, more viscous and has a much lower oxygen content.

47
Q

In bony fish, what are gills contained within?

A

A gill cavity covered by a protective operculum.