Fick's Law Flashcards
Give Fick’s law
rate of diffusion: P x SA x conc1 - conc2/thickness of diffusion surface
What is P in Fick’s law?
Permeability constant
What units must all the measurements of Fick’s law be in?
Micrometres
When does rate of diffusion double?
- If surface area/conc difference doubles
- If diffusion thickness halves
What 3 factors affect rate of diffusion?
- Concentration gradient
- Diffusion distance
- Surface area
What is the relationship between concentration gradient and rate of diffusion?
The steeper the concentration gradient the faster the rate of diffusion
How is a steep concentration gradient maintained in the alveoli?
- Good blood supply from capillaries
- Take away CO2 and bring more O2
How is a steep concentration gradient maintained in ventilation?
Ventillation replaces air with a low O2 concentration with air with a high O2 concentration
What is the relationship between diffusion distance and rate of diffusion?
The shorter the diffusion distance the faster the rate of diffusion
How is a short diffusion distance maintained in the body?
The alveolar epithelium and capillary endothelium are 1 cell thick
What is the relationship between surface area and diffusion distance?
The higher the surface area, the faster the rate of diffusion
How is a high surface area maintained in the alveoli?
- Many alveoli
- They are folded
Other than the alveoli, give 2 examples of diffusion surfaces
- Cristae
- Thylakoids
What is the pathway of oxygen transported into the blood?
Oxygen to alveoli across alveolar epithelium across capillary endothelium to blood
