PHGY 210 Lecture Notes - Lecture 9: Myoglobin, Carbonic Anhydrase, Haldane Effect
Jan 23, 2017
-watch out for the dots (hard to type so check her slides)
H. Measuring Pulmonary Blood Flow (Q-dot) Using Fick's principle
-O2 consumption per minute (VO2) is equal to O2 taken up by blood in lungs in one minute
-[O2] in blood entering lungs is CVO2 and that leaving is CaO2
-it then follows that:
or
-where:
-VO2: measured by comparing [O2] in expired gas collected in large spirometer
and [O2] in inspired gas
-CaO2: measured from artery
-CVO2: measured via catheter from pulmonary artery
find more resources at oneclass.com
find more resources at oneclass.com
V Transport of O2 and CO2
A.O2 Physically Dissolved in Plasma
-amount of dissolved gas carried by blood is directly proportional to partial pressure of gas
-Henry’s Law
-b/c O2 is relatively insoluble in H2O, amount of O2 dissolved in blood is very small and linearly
proportional to PO2
-ex: in 100 ml of plasma, there is 0.3 ml of O2 at PO2 of 100 mm Hg
-O2 consumption (VO2) by body cells is about 300 ml O2/min
-therefore, if O2 were only found in plasma, tissue demand for O2 would never be met
find more resources at oneclass.com
find more resources at oneclass.com
B. O2 Bound to Hemoglobin
-hemoglobin (Hb) is found in red blood cells
-permits whole blood to take up to 65 times as much O2 as plasma, at PO2 of 100 mm Hg
-each molecule of Hb consists of 4 subunits bound together
-each subunit is made up of heme joined to globin
-heme contains Fe++ ion that can bind to 1 molecule of O2
-Hb is essential for transport of O2 by blood b/c it combines rapidly and reversibly w/ O2
-at PO2 of 100 mm Hg, total amount of O2 dissolved in blood is 0.3 vol. % and total amount of
O2 bound to Hb is 19.5 vol. %
-this means that total amount of O2 in arterial blood is about 20 vol. %
-O2 bound to Hb does not contribute to PO2 of blood
-only molecules dissolved in blood plasma are responsible for PO2
-h/e, PO2 of plasma does determine amount of O2 that combines w/ Hb
C. O2 dissociation curve
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Watch out for the dots (hard to type so check her slides: measuring pulmonary blood flow (q-dot) using fick"s principle. O2 consumption per minute (vo2) is equal to o2 taken up by blood in lungs in one minute. [o2] in blood entering lungs is cvo2 and that leaving is cao2. Vo2: measured by comparing [o2] in expired gas collected in large spirometer and [o2] in inspired gas. Amount of dissolved gas carried by blood is directly proportional to partial pressure of gas. B/c o2 is relatively insoluble in h2o, amount of o2 dissolved in blood is very small and linearly proportional to po2. Ex: in 100 ml of plasma, there is 0. 3 ml of o2 at po2 of 100 mm hg. O2 consumption (vo2) by body cells is about 300 ml o2/min. Therefore, if o2 were only found in plasma, tissue demand for o2 would never be met: o2 bound to hemoglobin. Hemoglobin (hb) is found in red blood cells.
