Respiratory 6 & 7

Question 1

What quantity of oxygen is able to dissolve per litre of plasma?

Answer 1

3ml of oxygen

Question 2

What is the oxygen capacity per litre when utilising haemoglobin?

Answer 2

200ml/L

Question 3

Where is the bulk of carbon dioxide transported?

Answer 3

In the plasma

Question 4

True or false:

The arterial partial pressure of oxygen is the same as arterial oxygen content.

Answer 4

False.
Arterial partial pressure of oxygen refers only to the oxygen in solution, without taking into account the oxygen bound to haemolgobin.

Question 5

Which two factors determine the arterial partial pressure of oxygen?

Answer 5

• oxygen solubility

- the alveolar partial pressure of oxygen driving the oxygen into solution

Question 6

What is the usual arterial partial pressure of oxygen?

Answer 6

100mmHg

Question 7

What is the usual alveolar partial pressure of oxygen?

Answer 7

100mmHg

Question 8

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

Answer 8

25%

Question 9

Describe the binding relationship of oxygen and haemoglobin.

Answer 9

• co-operative
  As one oxygen molecule binds, the conformational change leads to an increased affinity for oxygen.
  The converse is also true.

Question 10

What is the term for the process of adding oxygen to haemoglobin?

Answer 10

Oxygenation

Question 11

Give a difference between oxygenation and oxidation.

Answer 11

Oxygenation is not as long lasting or chemically changing as oxidation.

Question 12

Which form of haemoglobin is most abundant?

Answer 12

HbA

Question 13

Which three forms of haemoglobin contribute to 8% of the bodies haemoglobin content?

Answer 13

• HbA2
• Foetal haemoglobin (HbF)
• Glycosylated haemoglobin (HbA (1a,1b and 1c) )

Question 14

What two types of chains does HbA contain?

Answer 14

• alpha

- beta

Question 15

What two types of chains does HbA2 contain?

Answer 15

• alpha

- delta

Question 16

What two types of chains does HbF contain?

Answer 16

• alpha

- gamma

Question 17

Why is glycosylated haemoglobin useful in diabetic patient reviews?

Answer 17

It can indicate the exposure of red blood cells to glucose over the lifespan of the haemoglobin (three months).

Question 18

What is the major determinant of haemoglobin saturation?

Answer 18

Partial pressure of oxygen in arterial blood.

As partial pressure increases, haemoglobin saturation increases.

Question 19

What is the total contact time between the alveoli and the haemoglobin?

Answer 19

Approximately 0.75s

Question 20

What is the steep slope of the oxygen-haemoglobin dissociation curve contributed to?

Answer 20

The co-operativity of oxygen.

Question 21

Does adult or foetal haemoglobin have the greatest affinity for oxygen? Explain your answer.

Answer 21

Foetal haemoglobin

This allows oxygen for the foetus to be extracted from maternal blood.

Question 22

Which region of partial pressure of oxygen is termed the ‘death zone’?

Answer 22

0 - 28mmHg

Question 23

Briefly define anaemia.

Answer 23

Any condition where the oxygen carrying capacity of the blood is compromised

Question 24

Is it possible to have a normal arterial partial pressure of oxygen and have a low total blood oxygen content?

Answer 24

Yes.

It is not possible however to have a low arterial partial pressure of oxygen and a normal total blood oxygen content.

Question 25

What are the four main chemical factors that alter haemoglobin affinity for oxygen?

Answer 25

- pH - temperature - partial pressure of carbon dioxide - diphosphoglycerate concentration

Question 26

What would a decrease in pH mean for haemoglobin affinity?

Answer 26

It would decrease.

Question 27

What would an increase in temperature mean for haemoglobin affinity?

Answer 27

It would decrease.

Question 28

What would a decrease in partial pressure of carbon dioxide mean for haemoglobin affinity?

Answer 28

It would increase.

Question 29

What would a decrease in DPG concentration mean for haemoglobin affinity?

Answer 29

It would increase.

Question 30

What is the Bohr effect?

Answer 30

Any shift to the right of the oxygen-haemoglobin dissociation curve.

Question 31

How many times greater is the affinity of haemolgobin for carbon monoxide compared to that of oxygen?

Answer 31

250 times greater!

Question 32

List the symptoms of CO poisoning.

Answer 32

- hypoxia - anaemia - nausea - headaches - cherry red skin and mucous membranes - brain damage - death

Question 33

Briefly define hypoxia.

Answer 33

Inadequate supply of oxygen to the tissues.

Question 34

List the five main cause of hypoxia.

Answer 34

- hypoxic hypoxia - anaemic hypoxia - ischaemic (stagnant) hypoxia - histotoxic hypoxia - metabolic hypoxia

Question 35

What cause of hypoxia would be characterised by a reduction in oxygen diffusion at the lungs either due to decreased atmospheric partial pressure of oxygen or tissue pathology?

Answer 35

Hypoxic hypoxia This is the most common cause of hypoxia.

Question 36

Describe the causes of anaemic hypoxia.

Answer 36

- reduction in oxygen carrying capacity of blood due to anaemia

Question 37

What cause of hypoxia is characterised by heart disease resulting in inefficient pumping of blood to the lungs and around the body?

Answer 37

Ischaemic (stagnant) hypoxia

Question 38

Describe the causes of histotoxic anaemia.

Answer 38

- poisoning prevents cells utilising oxygen delivered to them

Question 39

Describe the causes of metabolic anaemia.

Answer 39

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

Question 40

Why is the pH of the body normal stable?

Answer 40

All the carbon dioxide produced is eliminated in expired air.

Question 41

What affect would hypoventilation have upon pH levels?

Answer 41

- there would be carbon dioxide retention - leading to increased number of hydrogen ions - causing respiratory acidosis

Question 42

What affect would hyperventilaton have upon pH levels?

Answer 42

- there would be a 'blowing off' of carbon dioxide - leading to a decrease in the number of hydrogen ions - causing respiratory alkalosis