Lec 27 Flashcards
at equilibrium, partial pressure above and in solution are
equal
at equilibrium, concentration above and in solution are
not equal
CO2 is – more soluble than O2
20x
capacity of plasma for CO2 is
very low
total O2 in blood
dissolved in plasma + bound to hemoglobin
Hb bound to O2 is
Oxyhemoglobin
plasma carry – ml O2/L blood
3 ml
Hb carry – ml O2/L blood
197 ml
98% of total maximum load of oxygen
why O2-Hb dissociation curve is sigmoidal
cooperation
binding of the oxygen, increases binding affinity of the remaining sites
P o2 in tissues
0-40 mmHg
P O2 in alungs
60-100 mmHg
When P O2 is high, Hb is
saturated
highest saturation Hb is in
alveoli
why if Hb wasn’t wrking cooperatively
in tissues we should have gone to very small concentrations of O2 to be able to drop off oxygen
higher P50 of Hb saturation means
1-higher conc. of O2 required
2-affinity of O2 decreased
effect of pH on oxygen binding to Hb
lower pH
-reduce carrying capacity Hb
–more O2 dissociate as tissues need more
—p50 increases
—-when skeletal muscle activity is high happenes
effect of P CO2 on oxygen binding to Hb
higher P CO2
-body need more O2
–drop off O2 increase
—Hb affinity for O2 decrease
—-P50 increase
O2 transport in blood (lung)
O2 diffuse to plasma
due to high P O2 in plasma drives O2 binding to Hb
O2 transportt in blood (tissue)
O2 diffuse out to tissue
due to low p O2 in plasma derive O2 dissociation from Hb
CO2 transport in blood
1-7% dissolved in plasma
2-23% transport as HbCO2
3-70% transport as bicarbonate
CO2 binding to Hb
CO2 can bind to any group on Hb
bicarbonate formula and enzyme
CO2 + H2O –> H2CO3 –> H+ + HCO3-
enzyme: carbonic anhydrase
bicarbonate is an important —- in the body
buffer
CO2 binded Hb name
carbaminohemoglobin
CO2 transport near tissue
CO2 diffuse to plasma
major CO2 conc. will diffuse to blood
-23% bind with Hb
–70% react with water produce bicarbonate and H+
—bicarbonate will exchange with Cl- to enter plasma
—-H+ will buffered by Hb
CO2 transport near lung
CO2 diffuse to alveoli
-dure to low plasma CO2, CO2 will disociate first from Hb then from bicarbonate
sensory receptors convert chemical signal to
action potential
central chemoreceptors are located in
medulla
Chemoreceptors increase activity in response to
increased PCO2
central Chemoreceptors result after detecting high PCO2
increase rate and depth of respiration
peripheral chemoreceptors are located in
aortic arch and carotid sinuses
peripheral chemoreceptors increase activity in response to
high PCO2
low pH
low PO2
periphery Chemoreceptors result after detecting high PCO2
affrent signal to medulla
increase rate and depth of respiration
