Vascular
Biology,
Structure
and
Function
33
0.8
0.7
B
'I2
0.6
3
.-
0
0.5
5
0.4
n
2
0.3
u)
.-
u
0"
0.2
0.1
0
lsobestic point
-
Hb
Spectra
-
Absolute
I
I
I
700
800
900
nm
?
cytochrome c oxidase peak region
Fig.
2.3.2:
Optical absorptions of hemoglobin and oxy-hemoglobin. The isobestic point
is
at
805
nm. Cytochrome c oxidase absorption region is also indicated.
2.3.3
Red Blood Cells, Hematocrit and Blood Volume
The principal formed elements are erythrocytes or red blood cells (RBC
or rbc), leukocytes or white blood cells and thrombocytes.
The principal function of the red blood cell is in the transport of
oxygen
(02)
and carbon dioxide
(C02).
The concentration of hydrogen
ion (pH) determines the acidity/alkalinity. These three quantities (p02,
pC02 and pH) are the principal components involved in the blood gas
analysis. Some
of
the definitions from blood sample analysis are shown
below:
(2.3.6)
Re
dBloodCells
oo
Hematocrit, orHct(%)
=
(2.3.7)
Blood
Hct(tota1body)
Hct(venous)
Fcr
=
(2.3.8)
Mean corpuscular volume is defined as
