Gas exchange Flashcards
what is pressure?
force exerted per unit area. Gas exerts uniform pressure on all surfaces
how do gases exert pressure
- ) number of molecules that impact container
2. ) strength of impacts (Kinetic energy from temperature)
Ideal gas law
PV=nRT partial pressure (volume)= (amount of gas)(gas constant 0.082) (temp in kelvin)
boyles law
P1V1=P2V2 P∝1/V
at constant temp. pressure of gas is inversely proportional to the volume of gas
charles law
V1/T1=V2/T2 V∝T
at constant pressure volume of gas is proportional to temp. of gas
Gay boy lussacs law
P1/T1=P2/T2 P∝T
partial pressures of gas
N=79% O=21% CO2=.04% (.0004) (to find partial pressures just multiply by atmospheric pressure, but when air is humidified you must subtract partial pressure of h20 first )
henry’s law
[gas]=(PPgas)(solubility coefficient)
solubility coefficient is how easy it is for gas to dissolve in solution.
actual/ relative solubility of O2
.024/1
actual/ relative solubility of CO2
.57/24
actual/ relative solubility of N
.01/.5
actual/ relative solubility of He
.008/.33
diffusabilty
diffusion∝ ((delta P)(Area)(solubility))/((distance)(sqrt molecular weight))
surface area and distance constant for all gases. assuming the same pressure for all gases formula turns into :diffusion∝(solubility)/(sqrt (molecular weight))
movement of gas proportional
delta P, surface area, gas solubility,
movement of gas inversely proportional
distance, gas molecular weight
saturation
percentage of heme molecules bound with O2
oxyhemoglobin vs. deoxyhemoglobin
affinity
how easy it is for heme molecules to bind or release O2
high affinity: easy to bind hard to release
low affinity: hard to bind, easy to release
bohr effect
changes in [CO2] affects affinity for O2. increased CO2 decreases O2 affinity
haldane effect
changes in [O2] affects affinity for CO2. increases O2 decreases CO2 affinity
limiting factor of O2 utilization at tissue level
ADP
CO2 content dissolved in plasma
7%
total CO2 content bound to hemoglobin
23%
total CO2 content chemically modified to HCO3-
70%
Respiration
Transport of oxygen and CO2 in opposite direction
4 functions of respiration
Pulmonary ventilation (moving air between atmos. and alveoli)
Diffusion of O2 and CO2 between alveoli and blood
Transport of O2 and CO2 in blood and body fluids to and from tissue cells
Regulation of ventilation
Solubility coefficient
How easy it is for gas to dissolve in solution
Co2 is … Times more soluble than n2
57
Co2 is … Times more soluble than helium
71
Co2 is … Times more soluble than O2
24
Co2 is times more diff usable from O2
20.3
Define diffusability
Ability of gas to move through tissue and fluid
Oxygen gradient from alveoli to blood
64-65
Factors affecting O2/co2
Alveolar epithelial membrane lining,interstitial fluid, capillary membrane,plasma,red cell wall, red cell interior,chemical reaction
- ) main player with O2 is alveolar wall
- ) main player with co2 is chemical reac. From hco3-
Pressure gradient of co2 from blood to alveoli
5
Why does co2 not need the same pressure gradient as O2 to ensure adequate transfer at tissues?
Co2 is a lot more diffusable
O2 bound to hemoglobin vs dissolved
97/3
Non lethal range O2
10-1000 mmHG
Non lethal range co2
5-80 mmHG
Non lethal range sodium
115-175 mmol/L
Non lethal range potassium
1.5-9 mmol/L
Non lethal range calcium
.5-2 mol/L
Non lethal range pH
6.9-8 pH
Arterial /venous pressure of O2
95 mmHG vs 40mmHg
Arterial venous co2 pressure
40/ 45
Interstial po2 and Pco2
40/45
RBC po2 and co2 pressure
23/46
