Topic 8 - Exchange And Transport In Animals Flashcards

1
Q

How are gases exchanged into the lungs?

A

Diffusion.

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2
Q

What and how is the rate of diffusion affected by?

A

DISTANCE - substances diffuse more quickly when they haven’t got as far to move.
CONCENTRATION GRADIENT - Substances diffuse faster if there’s a big difference in concentration between the area they are diffusing from and the area they are diffusing to. If there are lots more particles on one side, there are more there to move across.
SURFACE AREA - The more surface are there is available for molecules t move across, the faster they can get from one side to the other.

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3
Q

What is the job of the lungs?

A

To transfer oxygen to the blood and to remove waste carbon dioxide from it.

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4
Q

What are alveoli?

A

Little air sacs where gas exchange takes place.

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5
Q

When blood arrives at the alveoli, why is concentration gradient maximised for both gases?

A

It’s just returned from the rest of the body so it contains lots of C02 and not much oxygen. This maximises concentration gradient for diffusion for both gases.

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6
Q

How is gas exchange taken place in the alveoli?

A

Oxygen diffuses out of the air in the alveoli (where oxygen concentration is high) and into the blood (where oxygen concentration is low). CO2 diffuses in opposite direction to be breathed out.

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7
Q

How are alveoli specialised to maximise the diffusion rate?

A
  • They have a moist lining for dissolving gases
  • They have a good blood supply to maintain the concentration gradients of O2 and CO2.
  • They have very thin walls to minimise the distance the gases have to move
  • They have a huge surface area (about 75m² in humans).
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8
Q

What is the rate of diffusion proportional to?

A
      Thickness of membrane
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9
Q

What is the job of red blood cells?

A

To carry oxygen from the lungs to all cells in the body.

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10
Q

How are blood cells specialised for carrying oxygen?

A
  • They have a biconcave disc shape to give a large surface area for absorbing oxygen.
  • They don’t have a nucleus - this allows more room to carry oxygen
  • They contain a red pigment called haemoglobin which contains iron.
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11
Q

What does haemoglobin do?

A

In the lungs, haemoglobin binds to oxygen to become oxyhemoglobin. In body tissues, the reverse happens - oxyhemoglobin splits up into haemoglobin and oxygen to release oxygen to the cells.

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12
Q

What are phagocytes and lymphocytes examples of?

A

White blood cells.

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13
Q

What do phagocytes do?

A

They are white blood cells that can change shape to engulf unwelcome microorganisms - this is called phagocytosis.

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14
Q

What do lymphocytes do?

A

They’re white blood cells that produce antibodies again microorganisms. Some also reduce antitoxins which neutralise any toxins produced by the microorganisms.

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15
Q

How can a blood test show if you have an infection?

A

When you have an infection, your white blood cells multiply to fight it off - therefore a blood test will show a high white blood cell count.

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16
Q

What are platelets and what do they do?

A

These are small fragments of cells that help the blood to clot at a wound - stop blood pouring out and microorganisms getting in.

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17
Q

What does plasma carry?

A
Red and white blood cells and platelets
Nutrients like glucose and amino acids
Carbon dioxide
Urea
Hormones
Proteins
Antibodies and Antitoxins
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18
Q

What are the three type of blood vessel and their functions?

A

ARTERIES - these carry blood away from the heart.
CAPILLARIES - these are involved in the exchange of materials at the tissues
VEINS - these carry blood to the heart.

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19
Q

How are arteries adapted to carrying blood out at high pressures?

A
  • Artery walls are strong and elastic
  • The walls are thick compared to the size of the lumen (hole down middle of artery)
  • They contain thick layers of muscle to make them strong and elastic fibres to allow them to spring back.
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20
Q

What do arteries branch into?

A

Capillaries.

21
Q

Why is it good that capillaries are narrow?

A

So they can squeeze in gaps between cells. This means they can carry blood really close to every cell in the body to exchange substances with them.

22
Q

Apart from being narrow, how else are capillaries specialised?

A

-They have permeable walls so substances can diffuse in and out
-They supply food and oxygen and take away waste like CO2
Their walls are usually one cells thick which increases the rate of diffusion by decreasing distance over which it occurs.

23
Q

How are veins formed?

A

By capillaries joining up to form veins.

24
Q

Why don’t the vein walls need to be as thick as the artery walls?

A

The blood is at lower pressure.

25
Q

How else are veins specialised?

A
  • They have a bigger lumen to help blood flow

- They have valves to help keep the blood flowing in the right direction.

26
Q

Whats a brief overview of the two circuits that the heart pumps the blood around the body in?

A

In the first circuit, the heart pumps deoxygenated blood to the lungs to take in oxygen. Oxygenated blood returns to the heart. In the second circuit, the heart pumps oxygenated blood around all the other organs of the body to deliver oxygen to the body cells. Deoxygenated blood then returns to the heart.

27
Q

How many chambers and blood vessels does the mammalian heart have?

A

Four chamber and four major blood vessels.

28
Q

What is the first stage of blood being pumped in the heart?

A

The right atrium of the heart receives deoxygenated blood from the body (through the vena cava)

29
Q

What is the second stage of blood being pumped in the heart?

A

The deoxygenated blood moves through the right ventricle, which pumps it to the lungs (via the pulmonary artery)

30
Q

What is the third stage of blood being pumped in the heart?

A

The left atrium receives oxygenated blood from the lungs (through the pulmonary vein)

31
Q

What is the fourth stage of blood being pumped in the heart?

A

The oxygenated blood then moves through to the left ventricle, which pumps it out round the whole body (via the aorta).

32
Q

Why is the left ventricle thicker then the right ventricle?

A

The left ventricle needs more muscle because it has to pump blood at higher pressures since it’s pumping blood around the whole body, whereas the right ventricle is only pumping blood to the lungs.

33
Q

What do valves do?

A

Prevent the back flow of the blood in the heart.

34
Q

How can you calculate how much blood is pumped every minute (cardiac output)?

A

Heart rate X Stroke volume.

35
Q

What is respiration?

A

It’s the process of transferring (releasing) energy from the breakdown of organic compounds (usually glucose).

36
Q

What is the energy released from the breakdown of organic compounds then used for?

A
Metabolic processes (such as making larger molecule from smaller ones)
Contracting muscles
Maintaining a steady body temperature.
37
Q

What are two types of respiration?

A

Aerobic and anaerobic.

38
Q

When does aerobic respiration happen?

A

When there’s plenty of oxygen available.

39
Q

What does aerobic mean?

A

With oxygen.

40
Q

What type of reaction is respiration?

A

Exothermic because energy is transferred to the environment.

41
Q

What is the word equation for aerobic respiration?

A

Glucose + Oxygen → Carbon Dioxide + Water

42
Q

What is the symbol equation for aerobic respiration?

A

C6H12O6 + 6O2 → 6CO2 + 6H2O

43
Q

When does anaerobic respiration happen?

A

When you do really vigorous exercise and our body can’t supply enough oxygen to your muscles for aerobic respiration - even though your heart rater and breathing rate increase as much as they can. Your muscles have to start anaerobically exercising as well.

44
Q

What does anaerobic mean?

A

Without oxygen.

45
Q

What disadvantage is there to anaerobic respiration?

A

The glucose is only partially broken down and lactic acid is also produced. The lactic acid builds up in muscles - it gets painful and leads to cramp.

46
Q

What is the word equation for anaerobic respiration in animals?

A

Glucose → Lactic Acid.

47
Q

How is plant anaerobic respiration different to animal respiration?

A

They produce ethanol and CO2 instead of lactic acid.

48
Q

What is the work equation for anaerobic respiration in plants?

A

Glucose → Ethanol + Carbon Dioxide.