Transport of Gases Flashcards
Total O2 Carrying capacity of blood:
O2 has a solubility in blood of what numerical value?
0.003
Calculating the amount of dissolved O2 in blood:
what are the units used when calculating?
mL O2/100mLs blood
Calculating the amount of dissolved O2 in blood:
what is the equation to calculate?
- 003 x PO2
* *PO2 is PaO2**
Calculating the amount of dissolved O2 in blood:
how much O2 is dissolved in arterial blood if PaO2 is 90mmHg
0.003 x 90 = 0.27 mL O2/ 100ml blood
Calculating the amount of dissolved O2 in blood:
Calculate the increase in dissolved O2 in the arterial blood if PaO2 increases from 50mmHg to 300mmHg
- 003 x 50 = 0.15 mLO2/100ml blood
- 003 x 300 = 0.90 mLO2 / 100mL blood
- 90 - 0.15 = 0.75 mLO2/100mL blood increase in dissolved O2
Calculating the amount of dissolved O2 in blood:
Who’s law permits the amount of O2 dissolved on O2 tom be calculated?
Henry’s Law
Calculating the amount of dissolved O2 in blood:
what are 2 things you need to know in order to do the calculation
Partial pressure
Solubility
Carriage of O2 by the blood Summary:
O2 is carried by the blood in 2 forms…what are they?
Hgb bound (chemical form) Dissolved (physical form)
Carriage of O2 by the blood Summary:
in a young healthy iundividual normal arterial blood (PaO2=100 mmHg) has _____ mLO2/100mL blood dissolved, and ___ mL O2/ 100mL blood bound to Hgb.
- 3 mLO2/100mL blood
19. 8 mlO2/100mL blood
Carriage of O2 by the blood Summary:
the maximum O2 carrying capacity of arterial blood of a healthy person breathing room air is what?
20.4 mL O2/ 100mL blood
Carriage of O2 by the blood Summary:
the maximum O2 carrying capacity of arterial blood of a healthy person breathing room air is 20.4 mL O2/100 mL blood, ____ mL of O2 is carried by Hb and ____ mL is dissolved
- 1 Hb
0. 3 dissolved
Carriage of O2 by the blood Summary:
the ODC is S shaped, the steep portion of the curve occurs when PO2 is less than 60 mmHg. clinical application: Hypoxia is defined as a PaO2
Carriage of O2 by the blood Summary:
As blood passes through the capillaries of metabolizing tissues, the ODC automatically shifts to the ____ b/c temperature and PCO2 are increased and the pH is decreased, this assist with the unloading of O2
right shift
Carriage of O2 by the blood Summary:
Blood passing through the Pulmonary capillaries gives up CO2 and pH Increases. The ODC shift to the ____. this facilitates the loading of O2 into Hgb
Left shift
Carriage of O2 by the blood Summary:
the ___ effect refers to the shift in the position of the ODC in response to changes in PCO2. according the this effect there will always be a rightward shift in the curve in response to an increase in PCO2 and a leftward shift in response to a decrease in PCO2
Bohr
Carriage of O2 by the blood Summary:
if fetal Hgb (HgF) is present the ODC shifts where?
left
Carriage of O2 by the blood Summary:
maternal Hgb exhibits a ____ shift
right
Carriage of O2 by the blood Summary:
if carboxyhemoglobin or methemoglobin is present there is a ___ shift
left
Carriage of O2 by the blood Summary:
most of the O2 carried in the blood is boud to ___, and only a very small fraction is dissolved
Hgb
Calculating the amount of O2 bound to Hgb:
what is “normal” Hgb concentration for equations
15 g hb/100 mL blood
Calculating the amount of O2 bound to Hgb:
to calculate you need to know what 3 things?
1) the amount of O2 carried by each gram of fully saturated Hb. (1.34 mL O2 per g Hb)
2) the normal concentration of Hb (15 g per 100 mL blood)
3) the % saturation (90% = 90/100 = 0.9)
Calculating the amount of O2 bound to Hgb:
what is the equation
O2 Hb = (1.34) x (15) x (0.9)
or O2 Hb = 1.34 x (hb) x % saturated
Calculating the amount of O2 bound to Hgb:
calculate the amount of O2 carried by Hb when it’s 90% saturated. (assume normal Hb concentration)
1.34 x 15 x 0.9 = 18.1 mL O2/ 100mL blood
Calculating the Total amount of O2 carried by the Blood:
what is simple equation
O2 bound to Hb + O2 dissolved in blood
Calculating the Total amount of O2 carried by the Blood:
Calculate the total amount of O2 carried by the blood when it is 90% saturated (assume normal Hb)
1.34 x 15 x 0.9 = 18.1 mL O2/ 100 mL blood
use ODC to find PaO2 90% = 60 mmHg
0.003 x 60 = 0.18 mL O2/ 100 mL/blood
18.1 + 0.18 = 18.28 mL O2 / 100mL blood
If SvO2 is 70% how much O2 is dissolved is venous blood
SvO2 70% = PvO2 40 mmHg
0.003 x 40 = 0.12 mL O2 / 100ml blood
what is another way of writing 100mL blood
dL blood
Normal values for Venous vs Arterial
Arterial O2 90% = ____ PaO2
Venous O2 70% = ___ PvO2
Arterial 60
venous 40
CO2 blood dissociation curve:
the ___ effect describes how changes in Partial pressure of O2 (PO2) in the blood influences the blood dissociation curve.
haldane effect
CO2 blood dissociation curve:
when PO2 in the blood increases, the blood CO2 dissociation curve shifts how?
down and to the right
CO2 blood dissociation curve:
when the PO2 in the blood decreases, the blood CO2 dissociation curve shifts how
up and to the left
CO2 blood dissociation curve:
what effect does Opioids have on the blood CO2 dissociation curve? why?
shifts it up and to the left b/c opioids decrease PO2 secondary to respiratory deprssion
CO2 blood dissociation curve:
Approximately 90% of the CO2 in transported by the blood is in the form of what?
HCO3-
Conversion of CO2 to Bicarbonate in RBC’s:
What is the balancing formula that this uses
CO2 + H2O H2CO3 HCO3- + H+
( = carbonic anhydrase)
(H2CO3 = carbonic acid)
Conversion of CO2 to Bicarbonate in RBC’s:
what principle is used for the to occur
LaChantelier’s principle
Conversion of CO2 to Bicarbonate in RBC’s:
so explain in basic terms how this occurs
- CO2 leaves cell into the plasma
- then diffuses into RBC
- Once in RBC CO2 uses colonic anhydrase to combine with H2O and form carbonic acid (CO2 + H2O = H2CO3)
- then carbonic anhydrase breaks down carbonic acid into bicarb and hydrogen (H2CO3 = HCO3- + H+)
- Hb (-) charged and are buffers for H+
- HCO3- then leaves the RBC freely and another (-) needs to enter so Cl- enters
CO2 is carried in the blood in 3 ways what are they?
1) in dissolved form
2) as Bicarbonate
3) chemically bonded to proteins (plasma proteins and HB)
Chloride Shift in NON-Pulmonary Capillaries:
explain it
- CO2 leaves cell into the plasma
- then diffuses into RBC
- Once in RBC CO2 uses colonic anhydrase to combine with H2O and form carbonic acid (CO2 + H2O = H2CO3)
- then carbonic anhydrase breaks down carbonic acid into bicarb and hydrogen (H2CO3 = HCO3- + H+)
- Hb (-) charged and are buffers for H+
- HCO3- then leaves the RBC freely and another (-) needs to enter so Cl- enters thus maintaining electroneutrality
- the exchange of Cl- for HCO3- is the chloride shift
Chloride Shift in NON-Pulmonary Capillaries:
the chloride shift is also called what
Hamburger shift
How do you calculate the amount of CO2 in dissolved blood?
PCO2 x 0.067
result in mL CO2 in 100mL blood
who’s law allows you to calculate the amount of CO2 dissolved in blood?
henry’s law
