3.1.1 exchange surfaces Flashcards

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1
Q

Do prokaryotes need specialised exchange surfaces?

A

No, they are small enough to get the resources they need via osmosis and diffusion etc.

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2
Q

Why do larger, eukaryotic organisms need specialised exchange surfaces?

A

Because they have greater metabolisms so they need more resources. They have lower SA:Volume ratios so cannot get all of their resources via simple diffusion, osmosis etc as the substances need to travel further to the internal cells.

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2
Q

How does having a large surface area aid exchange surfaces?

A

This allows more substances to travel across at a time which increases the exchange rate.

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3
Q

Why do mammals need excellent exchange surfaces?

A

Because they have large metabolisms.

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4
Q

Why does the trachea have c-shaped rings of cartilage?

A

To prevent it from collapsing due to the pressure changes in the lungs.

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5
Q

What two types of cells is the trachea lined by?

A

Goblet cells and Ciliated Epithelial cells.

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6
Q

What is the purpose of the Ciliated Epithelial cells in the trachea?

A

These cells sweep mucus, dust and bacteria away from the lungs and into the throat.

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7
Q

What is the purpose of the Goblet cells in the trachea?

A

They secrete mucus which traps dust and microbes which prevents them from reaching the lungs. The mucus is swept along by the cillia of the ciliated epitelial cells upwards and is swallowed.

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8
Q

Which cells line the alveoli?

A

Squamous epithelial cells (Very thin and permable so allow the diffusion of gases)

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9
Q

Where is smooth muscle found in the human exchange system?

A

In the bronchi and bronchiole walls.

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10
Q

What is the purpose of the smooth muscle walls of the bronchi and bronchioles?

A

This helps to regulate the flow of air into the lungs by dialating when more air is needed and constricting when less air is needed.

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11
Q

Which tissues in the lung are elastic fibres present in?

A

All lung tissues.

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12
Q

What are the purpose of elastic fibres in the tissues of the lungs?

A

Elastic fibres enable the lung to stretch and recoil which makes expiration a passive process.

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13
Q

What is the difference between the cartilage in the trachea and the cartilage in the bronchi?

A

The trachea has C-shaped cartilage rings whereas the bronchi has full rings of cartilage.

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14
Q

What is the trachea?

A

The airway that leads from the mouth and nose to the bronchi.

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15
Q

What do the bronchioles do?

A

These are narrow tubes that carry air from the bronchi to the alveoli.

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16
Q

What is the purpose of the alveoli.

A

These tiny sacs are the main site of gas exchange in the lungs.

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17
Q

Describe the process of inhilation in mammals.

A
  1. External intercostal muscles contract 2. Ribcage moves up and out
  2. Diaphragm contracts and flattens
  3. Thorax volume increases
  4. Thorax pressure decreases relatie to atmospheric pressure
  5. Air is drawn in down a PRESSURE gradient from a high to a low concentration.
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18
Q

Is inhilation an active or passive process?

A

Inhilation is an active process which requires ATP.

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19
Q

Why does breathing out technically occur?

A

Due to the recoil of the lungs as they have been stretched.

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20
Q

Explain the process of exhilation in mammals.

A
  1. External intercostal muscles relax. 2. Ribs move down and in 3. Diaphragm relaxes and curves upwards (dome shape) 4. Thorax volume decreases 5. Thorax pressure increases relative to atmospheric pressure 6. Air moves out down a PRESSURE gradient from a high to low pressure.
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21
Q

What is the function of the rib cage?

A

To protect the lungs.

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22
Q

What is the function of the diaphragm?

A

Contracts and relaxes to facilitate ventilation.

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23
Q

What is the function of the pleural fluid?

A

This reduces friction between the ribcage and lungs during inflation and deflation.

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24
Q

Why are the cartilage rings not complete in the trachea?

A

To allow the passage of food down the oesophagus behind the trachea.

25
Q

Do all bronchioles contain cartilage?

A

No, only the larger ones.

26
Q

What is ventilation?

A

The flow of air in and out of the alveoli.

27
Q

What are the two stages of ventilation?

A

Inspiration and expiration

28
Q

What is a spirometer used to measure?

A

A persons lung volume.

29
Q

Define tidal volume.

A

The volume of air that is normally breathed in OR out at rest.

30
Q

Define vital capacity.

A

The maximum volume of air that can be breathed in OR out in a single breath.

31
Q

Define residual volume.

A

The small volume of air which is always retained in the lungs and cannot be measured on a spirometer.

32
Q

Define breathing rate.

A

The number of breaths per minute.

33
Q

Define oxygen uptake.

A

The amount of oxygen consumed by the subject.

34
Q

Define total lung capacity.

A

The maximum volume of air in the lungs. Vital capacity + residual volume.

35
Q

How does a spirometer work?

A

It is a lid bobbing on a tank of water. A person breathes in and out through the mouthpiece (whilst wearing a nose clip) attached to a tube which leads into the water. Their breathing causes the lid to bob up and down, and it is attached to a pen which creates a trace on a revolving drum of paper

36
Q

How does the spirometer reduce carbon dioxide re-uptake?

A

Carbon dioxide is absorbed from the exhaled air by the sode lime in order to stop the concentration of carbon dioxide in the re-breathed air from getting too high.

37
Q

Why does a person using a spriometer wear a nose clip?

A

To ensure that the flow of air occurs only through their mouth which allows for accurate readings.

38
Q

Why does the spirometer have a canister of soda lime?

A

To filter the CO2 from the users limited air supply so they do not experience CO2 poisioning.

39
Q

Why do fish gills have a vivid red colour?

A

They contain many capillaries.

40
Q

How does an insects body allow air to enter the insect?

A

Insects have spiracles which are openings in the exoskeleton.

41
Q

Why do spiracles open and close?

A

To avoid excessive water loss.

42
Q

Explain the tracheal system of an insect.

A

-Air enters the insect through spiracles
-spiracles lead into trachea which are tubes that lead to the tracheoles.
-the tracheoles run in between individual cells which provides oxygen via diffusion.

43
Q

What is the function of the fluid at the end of the tracheoles?

A

This allows gases to dissolve and then diffuse into the cells.

44
Q

Why is there a size limit for how large an insect can be?

A

More cells would mean a higher demand for oxygen and the tracheal system could not meet this.

45
Q

Why do fish need a specialised exchange surface?

A

They have an impermable membrane so gases cannot diffuse through their skin.

46
Q

How many pairs of gils do bony fish have?

A

Four, each supported by a gill arch.

47
Q

What are found along the gill arches?

A

Projections called gil filaments with lamellae on them.

48
Q

What is the name of the gas exchange system in fish?

A

A counter-current system.

49
Q

Explain the counter-current system in fish.

A

Blood flows through the gil plates in one direction and water flows in the oppposite direction. This maintains a large concentration gradient between the water and the blood and makes sure that the water and blood concentration never reach equilibrium. The concentration of oxygen in the water is always higher than in the blood so the maximum amount of oxygen can diffuse into the blood from the water.

50
Q

Explain inspiration in bony fish.

A
  1. The fish’s mouth opens 2. The floor of the buccal cavity is lowered. 3. The buccal caivity volume decreases relative to the pressure outside. 4. Water moves into the buccal cavity and down a pressure gradient.
51
Q

Explain expiration in bony fish.

A
  1. The fish’s mouth closes 2. The buccal cavity volume decreases. 3. The buccal cavity pressure increases relative to gill cavity pressure. 4. Water moves into the gill cavity down a pressure gradient 5. This increases the pressure of the gill cavity relative to the pressure outside. 6. This increase in pressure opens the opperculum and water is pushed out of the gill cavity and over the gils.
52
Q

Explain some limitations of the fish dissection.

A
  1. It can be hard to see some of the finer, smaller structures within organs such as the lamellae. 2. The specamins do not reflect how the tissue would look in a living organism.
53
Q

As organisms increase in size, what happens to the surface area to volume ratio?

A

It decreases.

54
Q

What is an organisms basal metabolic rate?

A

The metabolic rate of an organism at rest.

55
Q

Where does the exchange of carbon dioxide and oxygen occur in the lungs?

A

Between the alveoli and the capilaries.

56
Q

Which process do oxygen and carbon dioxide undergo when they are exchanged between the alveoli and the capilaries?

A

Simple diffusion (passive movement from a high to low concentration).

57
Q

How does having one cell thick walls benefit the alveoli?

A

This means that gases have a very short diffusion distance so gas exchange is quick and efficient.

58
Q

How do humans benefit from having large numbers of alveoli?

A

This increases the surface area avaliable for oxygen and carbon dioxide to diffuse across.

59
Q

Name the fluid found in the tubes responsible for gas exchange in insects.

A

Tracheal fluid.