Lecture 18 Flashcards
What is dead space
Some of the inhaled air never gets to the alveoli so cannot gas exchange
Where does inhaled oxygen need to be transported to?
The capillaries
Where does carbon dioxide need to be transported to?
The alveoli so it can be exhaled
How do gases move across the membranes between the alveoli and the capillaries
Diffusion
What determines the rate of diffusion?
Surface area and the thickness of the membranes.
What is the equation for Fick’s Law of Diffusion
F = A/T x D (P1-P2)
What does the bulbous structure of the alveoli create?
Lots of surface area for gas exchange
What does the high density of capillaries create?
Lots of surface area for gas exchange
What is Emphysema?
A disease characterized by dilation of the alveolar spaces and destruction of the alveolar walls.
What does reduction in the surface area mean?
Less contact between the air and capillaries so oxygen exchange is greatly reduced
What is the Blood Air Barrier comprised of?
The alveolar and capillary walls
Pulmonary fibrosis
Thickening and scarring of the alveolar membranes. Can arise from chronic inflammation to industrial chemicals
What does PaO2 depend on? (Alveolar partial pressure of O2)
- Partial pressure of oxygen in inspired air
- Alveolar ventilation
- Oxygen consumption - Blood oxygen
Low activity of exercise
Reduced oxygen consumption and higher levels of O2 in the venous blood
The alveolar partial pressure of CO2(PaCO2)
- Partial pressure of CO2 in inspired air
- Alveolar ventilation
- Carbon dioxide production
