Week 20: (A) Respiratory Physiology Flashcards
What branches are the conductive zone?
1-16
What branches are the respiratory zone (acinus)?
17-23
How do we measure how much of a gas is in a space?
partial pressure
What is partial pressure?
The notional pressure of a constituent of gas if it alone occupied the entire volume of the original mixture at the same temp.
What percent room air is oxygen?
0.21/ 21%
What is the pressure of air at room temp?
760mm Hg
Does concentration of oxygen change with what state the has is in?
YES, room air has a higher concentration that water and blood (both the same)
Why do we use partial pressure?
Partial pressure refers to a number of gasses in an area
Tells us the direction which has moves, Conc does not!
Is partial pressure and Concentration proportional?
YES
What is the partial pressure exchange when O2 enter the alveolus?
atmospheric pressure = 156mm Hg to alveolar 100 mmHg
Where does the O2 in the airways dissolve?
Airway surface liquid (ASL) lining the alveolus
What is the O2 solubility in the ASL?
0.003ml O2/100ml/1mmHg
What is PO2 at 100mmHg in the ASL?
- 003ml X 100
0. 3ml O2/100ml ASL
how much oxygen does blood contain?
contains 0.003ml O2/100ml/1mmHg Po2
PLUS
All the O2 bound to haemoglobin (1.39ml O2/g Hb x Hb conc x %Hb saturation/ 100)
What is the PO2 of mixed venous blood that arrives at the lungs?
40 mmHg
What is the O2 conc of mixed venous blood arriving at the lungs with PO2 40mmHg ?
(40 x 0.003) + (1.39 x 15 x 75/ 100) = 0.12 + 15.64
–> 15.8 ml O2/100ml blood
What has higher O2 concentration, venous or ASL?
venous
venous= 15.8 ml
ASL = 0.3 ml
What has higher partial pressure, ASL or venous?
ASL
ASL= 100 mmHg
Venous = 40 mmHg
What would happen if O2 moved according to Conc gradients?
move from bloods to ASL out of the body.
what is the pathway of O2 entering the body? from dry room air to Cytochrome C oxidase…
Dry room air- 159 Tracheal gas- 149 Alveolar gas- 100 Pulmonary venous blood-98 Systemic arterial blood-96 mixed venous- 40 mitochondria-2 Cytochrome C oxidase -~0
What drives the surface area of alveoli?
the number of alveoli
What percent of the lungs is the respiratory zone?
95%