Oxygen Transport in the Blood

Question 1

What happens to the partial pressure oxygen throughout the system?

Answer 1

Gradually decreases from the air to the tissues

Question 2

What is the PO2 of oxygen in the air in kPa?

Answer 2

13.3

Question 3

What is the PO2 of oxygen in the tissues in kPa?

Answer 3

5.3 kPa

Question 4

What is Henry’s Law?

Answer 4

The amount of gas dissolved in a given volume & type of liquid is proportional to the partial pressure of the gas in equilibrium with the liquid at a constant temperature

Therefore the O2 amount dissolved in blood is proportional to partial pressure

Question 5

Why is the majority of oxygen not transported in dissolved form?

Answer 5

Because the amount of dissolved oxygen isn’t enough to maintain the cells’ viability

Question 6

How is most oxygen transported in the blood?

Answer 6

Bound to haemoglobin in Red blood Cells

Question 7

What does a molecules of haemoglobin consist of?

Answer 7

Hamm groups, alpa and beta chain with flat surfaces to contain oxygen + iron

Question 8

What is the function of haemoglobin?

Answer 8

To reversibly bind to oxygen

Question 9

How many oxygen molecules can each haem group reversibly bind?

Answer 9

One

Question 10

What is the primary factor in determination of % saturation of haemoglobin with oxygen?

Answer 10

Partial pressure of oxygen

Question 11

Dissolved O2 _______ with PO2 but not significantly

Answer 11

increases

Question 12

What does the oxygen concentration needed for haemoglobin saturation depend on?

Answer 12

Available haemoglobin

Question 13

What will occur in regards of haemoglobin if PO2 is normal?

Answer 13

It will become fully saturated

Question 14

What is the oxygen delivery index?

Answer 14

Function of oxygen content of arterial blood and cardiac index

Question 15

What is the cardiac index?

Answer 15

Relates the cardiac output to body surface area

Question 16

What is the normal range for the cardiac index?

Answer 16

2.4 - 4.2

Question 17

What is CaO2?

Answer 17

The oxygen content of arterial blood in ml/L

Question 18

What determines CaO2?

Answer 18

The haemoglobin concentration and the saturation of Hb with O2

Question 19

How many millilitres of oxygen does one haemoglobin molecule carry?

Answer 19

1.34 ml

Question 20

How can CaO2 be calculated?

Answer 20

1.34 x [Hb] x SaO2

Question 21

What is SaO2?

Answer 21

%Hb saturated with oxygen

Question 22

What can impair oxygen delivery to the tissues?

Answer 22

Decreased partial pressure of oxygen

Question 23

What can cause a decreased partial pressure of oxygen?

Answer 23

Respiratory disease
Anaemia
Heart failure

Question 24

How can respiratory disease decrease PO2?

Answer 24

Causes decreased arterial PO2 and therefore lower saturation of Hb as well as decreased blood oxygen content

Question 25

How can anaemia decrease PO2?

Answer 25

Decreases Hb concentration and therefore O2 content in the blood

Question 26

How can heart failure decrease PO2?

Answer 26

Decreases cardiac output

Question 27

What determines the partial pressure of oxygen in inspired air?

Answer 27

Atmospheric/Total pressure + proportion of oxygen in a gas mixture

Question 28

What is the proportion of oxygen in the atmosphere?

Answer 28

21%

Question 29

The air in the respiratory tract is saturated with water; how much does water vapour pressure contribute to total pressure?

Answer 29

Approx. 47 mmHg

Question 30

What is the standard PAO2 level?

Answer 30

100 mmHg at sea level

Question 31

What is meant by co-operative binding?

Answer 31

That when oxygen binds to Hb, Hb's affinity for oxygen increases

Question 32

What does the sigmoid shape of the oxygen-haemoglobin dissociation curve indicate?

Answer 32

That a moderate fall in PO2 will not affect oxygen loading much in distal tissues And that peripheral tissues get a lot more oxygen for a small drop in PO2

Question 33

What is the Bohr Effect?

Answer 33

That haemoglobin's oxygen binding affinity is inversely related to acidity and carbon dioxide concentration

Question 34

What does an increased PCO2 / [H+] / Temperature / 2,3-biphosphoglycerate show on the oxygen-haemoglobin dissociation curve according to the Bohr effect?

Answer 34

A shift to the right

Question 35

How does foetal haemoglobin differ in its structure from adult haemoglobin?

Answer 35

Hbf contains 2 alpha and 2 gamma subunits so it interacts less with 2,3-biphosphogylcerate in red blood cells

Question 36

HbF has a _____ affinity for O2 than HbA

Answer 36

higher

Question 37

Where is myoglobin present?

Answer 37

Skeletal and cardiac muscle

Question 38

How many haem groups does myoglobin contain?

Answer 38

1

Question 39

Myoglobin provides _______ O2 storage in ______ conditions

Answer 39

short-term | anaerobic

Question 40

What does the presence of myoglobin in the blood indicate?

Answer 40

Muscle damage