Gas transport in the blood Flashcards

1
Q

Where does blood transport oxygen to and from?

A

From the lungs to the tissues

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2
Q

Where does the blood transport CO2 to and from?

A

From tissues to lungs for removal

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3
Q

Name the two forms in which oxygen travels in the blood.

A

In solution in plasma
Bound to haemoglobin protein in RBC’s

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4
Q

How much oxygen travels in the plasma?

A

Very little- 3ml O2 /litre of plasma

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5
Q

How much O2 is there/litre of whole blood?

A

200ml

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6
Q

How much of the 200ml is bound to haemoglobin?

A

197ml

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7
Q

What is the bulk of CO2 transported in?

A

In plasma (77%)

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8
Q

How is the other 23% of CO2 transported?

A

Haemoglobin

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9
Q

What is the partial pressure of oxygen in the alveoli the same as?

A

The partial pressure of the plasma, at the point where equilibrium has been met.

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10
Q

Which is more soluble in water; oxygen or CO2?

A

CO2

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11
Q

How many haem groups does a molecule of haemoglobin have?

A

4

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12
Q

What does each haem group have?

A

One Fe2+ which binds to an oxygen molecule

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13
Q

How many molecules of oxygen does one haemoglobin molecule bind to?

A

Four

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14
Q

What is the major determinant of the degree in which haemoglobin binds/is saturated with oxygen?

A

Partial pressure of oxygen in the blood.

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15
Q

What is the partial pressure of oxygen is systemic arterial blood?

A

100ml mercury

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16
Q

What is the amount of oxygen carried by haemoglobin determined by?

A

The amount of oxygen in the plasma (partial pressure of O2 in the plasma).

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17
Q

What is the amount of oxygen in the solution of plasma is determined by?

A

Partial pressure of O2 in the alveoli.

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18
Q

What is the partial pressure of oxygen in the alveoli determined by?

A

Alveolar ventilation

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19
Q

How much oxygen can we deliver to our tissues every minute?

How much of this oxygen is used?

A

1000ml

250ml

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20
Q

Define anaemia xoxox

A

YAY
any condition where the oxygen carrying capacity of the blood is compromised.

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21
Q

Name three ways an individual may get anaemia xoxo

A

Iron deficiency
Haemorrhage
B12 defiviency

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22
Q

List the four factors which may alter the affinity of haemoglobin for oxygen.

A

pH
Temperature
PCO2 (partial pressure)
DPG

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23
Q

If the body needs more oxygen, what will happen to pH, temperature and PCO2 in order for the body to get access to the 75% of oxygen it does not usually have access to?

A

Lower pH
Increase temperature
Increase PCO2.

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24
Q

What happens if we increase pH and decrease temp and PCO2?

A

Haemoglobin’s affinity for oxygen increases and hangs onto it more tightly and will not give any to the peripheral tissues.

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25
Q

What is DPG a by product of?

A

The metabolism of red blood cells

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26
Q

Does DPG increase or decrease haemoglobin’s affinity for oxygen?

A

Reduces affinity

27
Q

Give examples of situations in which DPG production is increased.

A

Lung disease
Heart Disease
Individuals who live at high altitudes.

28
Q

STOP

Revision task coming up for everything learned so far :)

A

Look at Lecture 4.2-45 mins. Copy this out but add more detail to make sure you remember all important bits :)

29
Q

When does carbon monoxide form?

A

When there is incomplete combustion of carbon fuel (car exhaust fumes, lawnmower, faulty heating appliances etc.)

30
Q

What do you get when carbon monoxide joins w haemoglobin?

A

Carboxyhaemoglobin

31
Q

Why is carbon monoxide toxic?

A

Has very high affinity for haemoglobin so if there if there is any CO, it will bind tightly to haemoglobin and dissociate very slowly.

32
Q

Name some of the symptoms of someone who has CO in their body.

A

Hypoxia, anaemia, nausea, headache, cherry red skin and mucous membranes.
Respiration rate unaffected due to normal arterial PCO2. Potential brain damage and death.

33
Q

What is the treatment of CO?

A

100% oxygen to increase PO2.

34
Q

How is CO2 produced?

A

By product from cellular respiration

35
Q

How much carbon dioxide stays in the plasma after diffusing across the membrane?

A

7%

36
Q

What percentage of CO2 goes into red blood cells?

A

93%

37
Q

Carbon dioxide joins with deoxyhaemoglobin to form what?

A

Carbamino compounds

38
Q

What is produced if carbon dioxide reacts with enzyme carbonic anhydrase?

A

Carbonic acid is formed

39
Q

What happens in the chloride shift?

A

Exchange bicarbonate ions for chloride ions.

40
Q

What does carbonic acid split to give us?

A

Bicarbonate and hydrogen ions.

41
Q

What does the arterial partial pressure of oxygen solely refer to?

A

Oxygen in solution in plasma

42
Q

What is the arterial partial pressure of oxygen determined by?

A

Oxygen solubility

43
Q

What is the partial pressure of oxygen?

A

O2 in the gaseous phase that is driving O2 into solution

44
Q

What phases do gases not travel in the plasma and why?

A

Do not travel in the gaseous phase as would cause bubbles in the blood and a fatal air embolism!

45
Q

Name the process by which haemoglobin cooperatively binds four molecules of oxygen.

A

Oxygenation

46
Q

What is the most abundant form of haemoglobin in RBC’s?

A

Adult haemoglobin

47
Q

What % of haemoglobin in RBC does HbA make up?

A

92%

48
Q

What is the other 8% of haemoglobin composed of?

A

HbA2, HbF, glycosylated Hb

49
Q

Describe HbA2

A

Delta chains replace beta chains.

50
Q

Describe HbF

A

Foetal haemoglobin- gamma chains replace beta chains

51
Q

Which types of chain are in adult haemoglobin?

A

Alpha and Beta chains

52
Q

Why is glycosylated Hb important clinically?

A

Can be used in monitoring of diabetes and blood glucose control in diabetes.

53
Q

What is myoglobin?

A

Oxygen carrier molecule found only in cardiac and skeletal muscle.

54
Q

When might you see myoglobin in the blood?

A

If someone has extensive muscle damage

55
Q

Do myoglobin and foetal haemoglobin have a higher or lower affinity for oxygen compared to adult haemoglobin?

A

Higher affinity

56
Q

Why is foetal haemoglobin important?

A

Allows the foetus to access oxygen in maternal blood

57
Q

What is hypoxia?

A

Inadequate oxygen to tissues

58
Q

Name the five types of hypoxia.

A
  1. Hypoxaemic Hypoxia
  2. Anaemic Hypoxia
  3. Stagnant Hypoxia
  4. Histotoxic Hypoxia
  5. Metabolic Hypoxia
59
Q

Describe hypoxaemic hypoxia.

A

Reduction in O2 diffusion at lungs either due to decreased PO2atmos or tissue pathology.

60
Q

Describe anaemic hypoxia

A

Reduction in O2 carrying capacity of blood due to anaemia (red blood cell loss/iron deficiency).

61
Q

Describe stagnant hypoxia

A

Heart disease results in inefficient pumping of blood to lungs/around the body

62
Q

Describe histotoxic hypoxia.

A

Poisoning prevents cells utilising oxygen delivered to them e.g. carbon monoxide/cyanide

63
Q

Describe metabolic hypoxia

A

Oxygen delivery to the tissues does not meet increased oxygen demand by cells.

64
Q

What is the most common type of hypoxia?

A

Hypoxaemic hypoxia