Week 4: Gas Exchange & Transport Flashcards
respiration =
ventilation + gas exchange (diffusion)
What is diffusion
when molecules travel from a higher concentration to a lower concentration
total ventilation =
tidal volume - dead space * breathing frequency
total ventilation * no of breaths =
alveolar ventilation
what gases are involved in gas exchange and the diffusion process?
Nitrogen, oxygen, CO2, Argon
what is pressure measured in units?
mm Hg
air has to be humidified during inspiration: why?
as every expiration would remove water from the body
the partial pressure of oxygen in the conducting airways is?
lower
At the level of the alveoli what happens to the partial pressure of oxygen
the partial pressure of oxygen remains the same
the blood that comes into alveoli has very low
partial pressure of oxygen, as it has been used in the body
carbon dioxide diffuses?
diffuses into the alveoli
oxygen diffuses?
from the alveoli and into the red blood cells
oxygenated blood
has a higher partial pressure as it has taken things
What is the partial pressure of O2 and CO2 in the alveoli
PAO2 = 100 mm Hg
PACO2 = 40 mm Hg
What is the partial pressure of O2 and CO2 in the alveolar capillaries
PaO2 = 40 mm Hg
PaCO2 = 45 mm Hg
what are the components of the blood air barrier?
- alveolar type 1 epithelial cell
-basement membrane/interstitial space
-endothelial cell
-plasma
-erythrocyte membrane
what is the inner wall of the alveolus made up of?
alveolar type 1 epithelial cell
endothelial cell makes up a capillary: t or F
T
one of the limiting factors of diffusion is
thickness, hence the thicker the basement membrane the worse diffusion is, therefore the basement membrane is very thin to enable diffusion
cystic fibrosis
increases the distance and walls hence reduces diffusion
What is Ficks Law
the higher the concentration difference and the shorter the distance the better
higher concentration =
better diffusion
the bigger the surface area=
more diffusing
higher pressure difference =
more Volume of gas
