| Range |
during rest ~0.7: when cardiac output is maximal 0.3: in newborn infants 0.2 sec
|
| Organism |
Human Homo sapiens |
| Reference |
Brahm J, Wimberley PD. Chloride and bicarbonate transport in fetal red cells. J Physiol. 1989 Dec419: 141-56. p.142 top paragraphPubMed ID2621626
|
| Primary Source |
[1] Wagner, P. D. (1977). Diffusion and chemical reaction in pulmonary gas exchange. Physiological Reviews 57, 257-312. p.282 bottom paragraph [2] Hill, E., Power, G. G. & Longo, L. D. (1977). Kinetics of 02 and CO2 exchange. In Lung Biology and Health Series. Bioengineering Aspects of the Lung, vol. 3, ed. West, J. B., pp. 459-514. New York: Marcel Dekker.PubMed ID15292
|
| Comments |
"The
anion
exchange
system
of
red
cells
plays
a
central
role
in
the
transport
of
carbon
dioxide
from
the
tissues
to
the
lungs
by
the
blood.
The
presence
of
a
transport
system
that
mediates
the
obligatory
exchange
of
bicarbonate
for
chloride,
the
so-called
Hamburger
shift,
makes
it
possible
to
utilize
the
capacity
of
the
blood
to
transport
CO2
as
bicarbonate.
Considerations
based
upon
studies
of
chloride
and bicarbonate
exchange
at
body
temperature
(Wieth
&
Brahm,
1980
Wieth,
Andersen,
Brahm,
Bjerrum
&
Borders,
1982)
suggest
that
in
red
cells
from
adults
90
%
equilibration
occurs
within
about
0.4
s.
Hence,
approximately
99
%
equilibration
is
attained
within
the
transit
time
of
the
blood
in
the
capillary
(close
to
0.7
s
during
rest).
However,
the
CO2
transporting
capacity
of
blood
is
not
exploited
when
the
cardiac
output
is
maximal
under
which
conditions
the
transit
time
in
the
lung
capillary
may
be
reduced
to
as
little
as
0.3
s
(primary source [1]). In newborn infants, however, the transit time for a red cell in the lung capillary
may be even shorter, 0.2s, due to the incomplete development of the lungs of
newborn infants (primary source [2])." |
| Entered by |
Uri M |
| ID |
110883 |