respiratory 2

Question 1

oxygen cycle in lungs

Answer 1

1. ) oxygen uptake in the lungs
2. ) carrying capacity in the blood
3. ) global delivery from lungs to the tissue
4. ) regional distribution of oxygen delivery
5. ) diffusion of the capillary to the cell
6. ) cellular use of oxygen
7. ) carbon dioxide expired

Question 2

Oxygen transport We breath in air that

contains oxygen

Answer 2

1.) We breath in air that 
contains oxygen (approx.  21% at sea level)
2.) The oxygen diffuses across 
the alveolar membrane to 
the pulmonary capillaries 
until the pressure is equal
3.) About 3mL (1.5%) of this 
oxygen is dissolved in each 
litre of blood (PaO2). The 
rest attaches to the 
haemoglobin (98.5%) (Low 
concentration of oxygen in 
the blood is called 
HYPOXAEMIA) 
4.) The cardiac system pushes 
the blood around the body 
to supply the oxygen to all 
the body organs and cells. 
5.)Oxygen moves from the 
plasma (blood) to the 
organs/tissues where it is 
needed/used (Cellular 
respiration). Oxygen that is 
attached to haemoglobin 
can then move from the 
haemoglobin into the 
plasm

Question 3

DaO2 equation

Answer 3

= CaO2 x CO

Question 4

Hypoxia occurs when

Answer 4

1. Arterial blood O2 content is decreased (HYPOXAEMIA)

2. Cardiac output or perfusion is decreased

Question 5

Transport of Carbon dioxide

Answer 5

Transported by the blood back to the lungs where it is expired

Question 6

As blood gives up oxygen to respiring tissues/cells (becomes deoxygenated)

Answer 6

it
is able to take up more carbon dioxide (CO2) than what the tissues are
producing.

Question 7

• Conversely, oxygenation of haemoglobin in the lungs assists

Answer 7

the unloading of

CO2 from the blood so that it can be expired

Question 8

The gas in the alveoli is in equilibrium

Answer 8

with arterial blood (PACO2 and PaCO2)

Question 9

Doubling the alveolar ventilation halves alveolar and arterial PCO2

Answer 9

and halving

the alveolar ventilation doubles PACO2 and PaCO2