L16: Carriage Of Oxygen

Question 1

What does diffusion depend on

Answer 1

Partial pressure gradient

Question 2

What are the 2 ways oxygen is carried

Answer 2

1) physically dissolved in plasma

2) chemically bound to haemoglobin in RBC

Question 3

What does the oxygen dissolved in plasma exert

Answer 3

Partial pressure

Question 4

What is the chemical combination of oxygen with haemoglobin determined by

Answer 4

Partial pressure hence the oxygen in the plasma

Question 5

What is Henry’s law about

Answer 5

How much gas is dissolved in the liquid (plasma)

Question 6

Why do we need the chemical combination of oxygen with haemoglobin if oxygen can be dissolved physically in plasma

Answer 6

The dissolved oxygen in plasma is not enough for the body

Question 7

Inside the haem group which iron allows oxygen to bind

Answer 7

Iron (Fe2+)

Question 8

What is co-operative binding

Answer 8

Binding of oxygen to iron in haemoglobin makes the binding and unwinding of other oxygen binding to other haem easier and

Question 9

What does oxygen content mean

Answer 9

The amount of oxygen in:

dissolved in plasma AND bound to haemoglobin

Question 10

What does oxygen capacity mean

Answer 10

The maximum amount of oxygen that combines with haemoglobin in blood

Question 11

Does the oxygen capacity involve the oxygen in dissolved plasma

Answer 11

No

Question 12

What is oxygen capacity only dependent on

Answer 12

Concentration of haemoglobin

Question 13

At what pao2 is the haemglobin 100% saturated

Answer 13

Normal pao2 of 13kpa

Question 14

What does a flat association curve indicate

Answer 14

Despite the change of Po2 from 8-13kpa most of oxygen is still bound to haem

Question 17

What is 2,3-DPG

Answer 17

Side reaction of glycolysis

Question 18

What does the flat association curve indicate

Answer 18

Despite the changes from 13 to 8kpa the haemoglobin is still 90% saturated (enough for a persons oxygen delivery)

Question 19

What does the steep dislocation curve indicate

Answer 19

Despite the changes from 8 to 3kpa the haemoglobin concentration is desaturated by 60%

Question 19

What does the steep dissociation curve ensure

Answer 19

Delivery of oxygen for tissue

Question 20

How can the oxygen binding affinity to haemoglobin be shifted to the right

Answer 20

Increase pco2 in arterial blood
Decrease ph
Increase temperature
Increase 2,3DPG concentration

Question 21

What are the factors that affect the haemoglobin concentration

Answer 21

Diet
Reduced RBC (anaemia)
Carbon monoxide poisoning

Question 21

What is the Bohr effect

Answer 21

Increasing pco2

Decreasing ph

Question 21

When do we get an increase in pco2, increase in H+ (decreasing ph) and increase in temperature

Answer 21

At a high metabolism

Question 21

What does a right shift in the hb dissociation allow

Answer 21

Allow a further amount of oxygen delivery to the tissue

Question 21

What is the auto regulated delivery in tissues

Answer 21

Amount of oxygen delivered is depends on how fat the curve is shifted to the right and how the metabolism has changed

Question 21

Does pao2 have any affect on the hb dissociation curve

Answer 21

No

Question 21

Is the ability to deliver oxygen in anaemia affected

Answer 21

No

Question 21

Where does carbon monoxide bind

Answer 21

Same site as oxygen in haemoglobin

Question 23

Why is carbon monoxide more fatal than anaemia

Answer 23

Oxygen is not released from the haemoglobin until tissue po2 is 1kpa And at 1kpa the tissues are dying

Question 25

What are the variants of haemoglobin in RBC

Answer 25

``` Adult haemoglobin Fetal haemoglobin Haemoglobin S Metheoglobineaemia Mygoblobin ```

Question 26

What is the affinity for oxygen for fetal haemoglobin compared to adult haemoglobin

Answer 26

Higher affinity

Question 27

Why does fetal haemoglobin have a higher affinity for oxygen

Answer 27

To pick up oxygen in maternal blood

Question 28

When do we get haemoglobin s

Answer 28

In sickle cell anaemia

Question 29

Which direction does sickle cell anaemia shift the hb dissociation curve

Answer 29

Right

Question 30

What is myoglobin

Answer 30

Oxygen store in muscle with one haem group

Question 32

What is hypoxia

Answer 32

Low oxygen in the blood for delivery or consumption for tissues to maintain normal function

Question 34

What are the types of hypoxia

Answer 34

Hypoxic hypoxia Anaemic hypoxia Stagnant hypoxia Histotoxic hypoxia

Question 35

Wha is hypoxic hypoxia

Answer 35

Low arterial oxygen and low saturation of oxygen

Question 36

What are the clinical conditions that cause hypoxic hypoxia

Answer 36

Hypoventialtion Diffusion limitation V/Q mismatch Shunt

Question 37

What is anaemic hypoxia

Answer 37

Normal pao2 and normal staturation of oxygen but low oxygen conten

Question 38

What are the clinical conditions of anaemic hypoxia

Answer 38

Blood loss | Carbon monoxide poisoning

Question 39

What is stagnant hypoxia

Answer 39

Low blood flow in a small tissue or large tissue

Question 40

What are the clinical conditions that give stagnant hypoxia

Answer 40

Cardiac failure

Question 41

What is histotoxic hypoxia

Answer 41

High venous oxygen and high saturation of venous oxygen due to inability to utilise oxygen

Question 42

What are the clinical conditions that result in histotoxic hypoxia

Answer 42

Cyanide poisoning