Lecture 3- Gas transport Flashcards
less than …% of the oxygen in the blood is dissolved and this amount represents what is available to diffuse
2%
98% of O2 in the blood is …
bound to hgb
hgb is a … pigment found in …. erythrocytes
respiratory
mammalian
hgb is the predominant protein i nerythrocytes, estimates of …. million hb molecules per cell
250-280 million
hgb is a …. molecule meaning it has … protein subunits, each has a …. group that includes 1 iron atom that can …. bind O2
tetrameric
4
heme
reversibly
O2 carrying capacity of hgb
0-4
the plateau region of the o2-hgb dissociation curve is the …. phase
loading
the steep region of the o2-hgb dissociation curve is the … phase
unloading
as PO2 decreases in the blood, hgb’s affinity for O2 rapidly …
decreases
P50 is the PO2 at which half of the hgb is …
saturated
PO2 is a measure of …. O2 and ONLY … O2 can diffuse into tissues
dissolved
it is critical to maintain a pool of dissolved O2 to supply….
mitochondrial demand
there will be an increase in hgb’s affinity for oxygen if there is a shift of the curve to the …. and hgb is saturated at a lower PO2
left
There will be a decrease in hgb’s affinity for oxygen if there is a shift of the curve to the …. and hgb is less saturated for a given PO2
right
what shifts the curve to the right
increased temp
increased acidity
added DPG
what shifts the curve to the left
decreased temo
decreased acidity
no DPG
is arterial PO2 cahnged in anemia or CO poisoning?
no, but total O2 content is reduced
hgb affinity for CO is …. than for O2
200 fold greater
CO2 is transported in 3 forms
dissolved (7%)
bound to hgb (23%)
as HCO3 (70%)
CO2 binds to globin portion of hgb to form ….
carbaminohemoglobin
CO replaces O2 on hgb competing for binding sites on hgb and forms …
carboxyhemoglobin
if PCO2 is increased, then hgb’s affinity for CO2…
increases
if PO2 decreases, hgb’s affinity for CO2…
increases
the CA reaction … plasma
acidifies
… is the enzyme that catalyzes the formation of carbonic acid
carbonic anhydrase
Carbonic anhydrase is found in … not ….
erythrocytes
plasma
erythrocytes have a … transporter that moves… into the plasma
HCO3/Cl
HCO3
H+ binds to …. residues on hgb and hgb buffers most of the H+ produced by CA
histidine
oxyhgb affinity for H+ is …
low
deoxyhgb affinity for H+ is …
high
in the tissues, hgb picks up … and minimizes effect of … on pH
H+
HCO3
hypoventilation leads to
respiratory acidosis
hyperventilation leads to
respiratory alkalosis
hypoventilation, respiratory acidosis is when theres a …. in PCO2 and H+
increase
hyperventilation, respiratory alkalosis is when theres a … in PCO2 and H+
decrease
the oxy-hgb curve describes the effect of … on hgb saturation
PO2
P50 is the PO2 at which …. of hgb is saturated
1/2
2,3 DPG is a product of … in erythrocytes that enhances offloading/dissociation of O2 by allosteric modulation
glycolysis
breath holding is extreme
hypoventilation
