Pulmonary blood flow, gas exchange and transport 2+3

Question 1

How many millilitres of oxygen is dissolved in the plasma?

Answer 1

3ml

Question 2

What compound increases the oxygen content of the blood to 200ml/l?

Answer 2

Haemoglobin

Question 3

How is the bulk of CO2 transported in the plasma?

Answer 3

In solution

Question 4

What oxygen is the only part which makes up the partial pressure of oxygen?

Answer 4

The oxygen in solution (3ml)

Question 5

What 2 things is the partial pressure of oxygen determined by?

Answer 5

• Oxygen solubility which is fixed

- Partial pressure of oxygen in alveoli which is the gas driving oxygen into solution

Question 6

Why is the oxygen in alveoli and in the blood the same pressure?

Answer 6

The partial pressure of gas in solution is equal to the partial pressure in the gaseous phase driving the gas into solution

Question 7

What is oxygen tension?

Answer 7

PaO2=100mHg in alveoli

Question 8

Why do gases not travel in the blood?

Answer 8

Would lead to bubbles in the blood = fatal air embolism

Question 9

What percentage of arterial oxygen is extracted by peripheral tissues at rest?

Answer 9

25%

Question 10

What is the oxygen demand for resting tissues?

Answer 10

250ml/min

Question 11

Is the process by which haemoglobin binding oxygen knows as oxidation or oxygenation?

Answer 11

oxygenation

Question 12

For 1g of haemoglobin how many ml of oxygen is bound?

Answer 12

1.34ml

Question 13

How much of haemoglobin is HbA?

Answer 13

92%

Question 14

What is the other 8% of haemoglobin?

Answer 14

HbA2, HbF and glycosylated Hb

Question 15

Describe HbA2

Answer 15

delta replace beta

Question 16

Describe HbF

Answer 16

Gamma replace beta

Question 17

Name the 3 glycosylated haemoglobin

Answer 17

HbA1a, HbA1b and HbA1c

Question 18

What is the major determinant of the degree to which haemoglobin is saturated with oxygen?

Answer 18

Partial pressure of oxygen in arterial blood

Question 19

How long after contact is Hb saturated?

Answer 19

0. 25s

0. 75s total

Question 20

When alveolar P02 Is moderately reduced how much is the oxygen uptake by the blood affected?

Answer 20

Stays relatively normal

Question 21

What is the oxygen capacity of normal venous blood - Po2?

Answer 21

75%

Question 22

Why do fetal haemoglobin and myoglobin have a higher affinity for oxygen than Hba?

Answer 22

Extract oxygen from the maternal or arterial blood

Question 23

Anaemia

Answer 23

Any condition where the oxygen capacity of blood is compromised

Question 24

What are 3 examples of anaemia?

Answer 24

Iron deficiency, haemorrhage and vitamin B12 deficiency

Question 25

How is haemoglobin still fully saturated in anaemia?

Answer 25

P02 is normal as oxygen in solution is unaffected

Question 26

Name the 4 chemical factors which affect the affinity of Hb for O2

Answer 26

pH, PCO2, temperature and DPG

Question 27

Why does exercise shift the curve to the right?

Answer 27

Facilitates dissociation

Question 28

What does a rise in pH do for saturation of haemoglobin?

Answer 28

Increases affinity and makes unloading more difficult

Question 29

What does a rise in pH aid?

Answer 29

Collection of oxygen in the pulmonary circulation

Question 30

What synthesises 2,3-DPG?

Answer 30

Erythrocytes

Question 31

Does 2,3-DPG binding increase or decrease affinity of Hb and oxygen?

Answer 31

Decreases

Question 32

When does 2,3-DPG increase?

Answer 32

When there is inadequate oxygen eg heart and lung disease or at altitude

Question 33

What does 2,3-DPG help to maintain?

Answer 33

Oxygen release

Question 34

What do carbon monoxide and haemoglobin combine to form?

Answer 34

Carboxyhaemoglobin

Question 35

How much greater is CO affinity than O2?

Answer 35

250 times

Question 36

Why is Co binding a problem?

Answer 36

Binds readily and dissociates slowly

Question 37

What partial pressure of CO is enough for progressive carboxyhaemoglobin production?

Answer 37

0.4mmHg

Question 38

Symptoms of CO

Answer 38

Hypoxia, anaemia, cherry red skin and mucous membranes, nausea, vomiting and potential brain damage and death

Question 39

Is the respiration rate affected in CO? Why?

Answer 39

PaCO2 normal so unaffected rate

Question 40

Name the 5 types of hypoxia

Answer 40

``` Hypoxic Anaemic Ischaemic/stagnant Histotoxic Metabolic ```

Question 41

Hypoxic hypoxia

Answer 41

Most common and found at altitude where there is a reduced PO2 in the atmosphere leading to a reduction in oxygen diffusion at the lungs

Question 42

Anaemic hypoxia

Answer 42

Reduction in oxygen carting capacity due to anaemia - RBC loss and iron deficiency

Question 43

Ischaemic hypoxia

Answer 43

Heart disease leading to an inefficient pumping of blood

Question 44

Histotoxic hypoxia

Answer 44

Due to poisoning of CO or cyanide so cells cannot use oxygen

Question 45

Metabolic hypoxia

Answer 45

The oxygen is not meeting the metabolic demand of cells `

Question 46

How much CO2 is dissolved in plasma/RBC?

Answer 46

7%

Question 47

CO2 + deoxyhaemoglobin==>>?

Answer 47

Carbamino compounds

Question 48

How much of total CO2 and where are carbamino compounds formed?

Answer 48

23% | Erythrocytes

Question 49

How much carbon dioxide combines with water?

Answer 49

70%

Question 50

What does CO2 + H2O make?

Answer 50

Carbonic acid in RBC

Question 51

What does carbonic acid dissociate to give?

Answer 51

H+ and bicarbonate

Question 52

What does bicarbonate exchange with when moving into plasma?

Answer 52

Chloride ions ( chloride shift)

Question 53

What do H+ combine with?

Answer 53

deoxyhaemoglobin

Question 54

Respiratory acidosis occurs in hypo or hyperventilation?

Answer 54

Hypoventilation - retains CO2 so H+ increases

Question 55

Respiratory alkalosis occurs in hypo or hyperventilation?

Answer 55

Hyperventilation