Physiology lecture 3 Flashcards
does diffusion of gases across respiratory membrane require energy consumption?
no its passive
diffusion of gases determined by what two laws
Fick’s and Henry’s
what are the factors of Fick’s law
thickness of respiratory membrane
surface area
diffusion coefficient
partial pressure difference
thickness of respiratory membrane relationship to rate of diffusion and what is smth that decreases it
inverse proportional
pulmonary edema and fibrosis
surface area relationship to rate of diffusion and what is smth that decreases it
directly proportional
lobectomy and emphysema
diffusion coefficient relationship to rate of diffusion
directly proportional
what does diffusion coeff depend on
solubility coef and molecular weight of gas
diffusion coef relationship to molecular weight and solubility coeff
molecular weight inverse
solubility coef direct
is the diffusion coef high or low for gases with low molecular weight
high and high rate of diffusion
arrange gases which diffuses faster to slowest
CO2 then O2 then N2
Partial pressure difference relationship to rate of diffusion
directly proportional
as partial pressure of gas increase the rate of diffusion ……
increase
partial pressure of oxygen in alveoli and in pulmonary capillary and what is the pressure gradient
alveoli 100
capillary 40
pressure gradient 60
partial pressure of carbon dioxide in alveoli and in pulmonary capillary and what is the pressure gradient
alveoli 40
capillary 45
pressure gradient 5
what is henrys law
amount of gas dissolved is proportional to its partial pressure
solubility of gas relationship to rate of diffusion
directly proportional
what affects solubility of gas
temperature
solubility coeff
pressure gradient
the pressure gradient for O2 is 10 -12 times higher than co2 but why is the diffusion rate for CO2 higher
CO2 has higher solubility coeff and higher diffusion coeff
what is external respiration
movement of gas between alveoli and pulmonary capillary
blood in arteriorlar end of pulmonary circulation , which gas is higher and which is lower in comparison to alveolar air
lower oxygen and higher co2
blood in venular end of pulmonary circulation , which gas is higher and which is lower in comparison to alveolar air
same oxygen and carbon dioxide conc as alevolar air
what are the factors driving the movement of gas
partial pressure gradient and solubility of gas
the concentration of oxygen in alveoli is determined by
rate of oxygen absorption from alveoli to blood
rate of entry of new oxygenated air from atmosphere
during exercise what parameters increase
pulmonary ventilation
pulmonary blood flow
pulmonary surface area
what are the abnormalities affecting external respiration
hypoxia and anoxia
what is hypoxia
low oxygen in tissues limiting metabolic activity
what is anoxia
no oxygen supply to tissues leading to heart attack or CVA
What are the factors that cause low arterial partial pressure of oxygen
not enough ventilation
problem in gas exchange between alveoli and capillary
not enough oxygen is transported in blood (carbon monoxide poisoning)
what happens to oxygen of blood in pulmonary vein when it mixes from capillaries around it during internal respiration
slightly decrease
what gas levels affect bronchiole diameter and how
carbon dioxide
when PCO2 in expired air increases the bronchiole diameter increase
what gas level affect arteriole diameter and how
alveolar gas level
high co2 and low o2 causes pulmonary arteriole constriction
low co2 and high o2 causes pulmonary arteriole dilation
what are the ways co2 is transported in blood and percentages
70% as bicarbonate
23% bound to hb ( carbaminohb)
7% dissolved in plasma
the carbon dioxide bound to hb binds to what part and reversible or not
bind to amino group and reversibly
what is the total percentage of co2 that diffuses into RBCs
93%
each 100 ml of blood carries how many ml of CO2 and O2
Co2 ; 4ml
O2;20 ml
how does bicarbonate leave RBC
by chloride shift (exchanged with extracellular chloride)
what % of oxygen is transported in blood and what % in plasma
blood 98%
plasma 1.5%
carbon monoxide affinity is greater or lower to hb in comparison to oxygen
200 times more
what does the oxygen hb saturation curve represent
percentage of heme units that are bound to oxygen
what does the curve reflect
increased affinity for oxygen (sigmoid)
hb is more than 90 % saturated when PO2 is
more than 60 mmhg
hb entering systemic circulation how much is it saturated
100%
hb leaving body tissues how much is it saturated
75%
is substantial o2 reserve present in venous blood
yes
hb in blood in active muscles by how much is it saturated and what is the po2 there
20%
po2 = 15-20 mmhg
at high po2 the saturation is high
true
what are the factors that shift the curve to right
2,3 BPG
low PH (high H+)
high temp
high pco2
when curves shift to right , at the same partial pressure, the hb saturation will be less
true
higher BPG means more oxygen will be released by hb
true
if BPG drops very low hb will not release oxygen
true
what limits the storage of blood
BPG
What factors increase BPG
thyroxine
NE
EN
Growth hormone
