Respiratory Flashcards
Normal partial pressures of oxygen in atmospheric air are?
PiO2 = 21.2 kPa (159.2 mmHg)
Normal partial pressures of oxygen in Alveolar gas is?
PAO2 = 14 kPa (105 mmHg)
Normal partial pressures of oxygen in arterial blood is?
PaO2 = 13.3 kPa (100 mmHg)
Normal partial pressures of oxygen in mixed venous blood is?
PvO2 = 5.3 kPa (40 mmHg)
What are the Conducting zone and what are they volume and functions?
- No alveoli
- Includes generations 1 – 16, trachea to terminal bronchioles
- Volume 150 ml
- Function
1. Bulkflow during inspiration and expiration
2. Warming and humidification of inspired air
What is the respiratory zone and what are they volume and function?
- Has alveoli
- Includes generations 17 to 23, respiratory bronchioles to alveolar sacs
- Volume 3000 ml
- No bulk flow, gases move by diffusion down concentration gradient
Function
Gas exchange
What are the characteristics of the ideal alveoli?
Perfused normally
Ventilated normally
What is the function of alveolar ventilation?
Delivers O2 to the alveolus
Removes CO2 from the alveolus
What are the factors that affect gas exchange?
- Dead space
- Diffusing capacity
- Shunt
What is dead space?
The proportion of tidal volume not involved in gas exchange.
What is diffusion capacity?
The volume of a gas that can be transferred across a membrane per unit time.
What is shunt?
The proportion of the blood entering the left side of the heart that has bypassed the oxygenation process of the lungs.
What dose the anatomical dead space consist of?
- Upper airway – nose and pharynx
- Conducting zone
What is the equation of the minute ventilation?
AMV = (TV - DSV) x RR
AMV = Alveolar minute ventilation
TV = Tidal volume
DSV = Dead space volume
RR = Respiratory rate
What is the alveolar dead space?
Alveolar dead space consists of the proportion of AMV that does not take part in gas exchange due to entering either unperfused alveoli, where no gas exchange occurs, or underperfused alveoli, where gas exchange is incomplete.
