Biomedical Engineering Reference
In-Depth Information
(b) What basic parameters are determined in this model and do they have any
physical meaning?
(c) What limitations are there in this model?
(d) What can you say about the effects of the volume of inhalation volumetric
flow rate and blood volumetric flow rate on the model?
Inhaled Air
Exhaled Air
Alveolus
Lungs
Blood vessel
10.18 A radioactive tracer experiment is performed in order to measure the flow
rate of blood in a blood vessel (stream 3). The concentration of the tracer in
the inlet and outlet blood streams is determined via autoradiography. A com-
partmental schematic of the experiment is shown in the table. Four different
experiments were performed. For this set of experiments, determine the aver-
age blood flow rate, in mL/min, with 95% confidence limits for blood out.
Tracer in
Tracer
Concentration
(ppm)
Blood In,
Tracer
Concentration
(ppm)
Blood Out,
Tracer
Concentration
(ppm)
Tracer in
Flow Rate
(mL/min)
Experiment
1
1.73
4,007
345
732
2
1.67
3,999
472
847
3
1.69
4,013
507
875
4
1.60
4,002
523
900
Tracer in
Blood
in
Blood
out
are time
−1
and length.
10.20 For an infinitely long cylindrical element, show that
10.19 Show that the units of
τ
m
and
λ
x
−
at
ΔΦ = ΔΦ
e
λ
0
steady-state.
10.21 The membrane resistance of a long cylindrical cell (diameter 80
μ
m) is 120
Ω
cm
2
. The resistance of the cell axoplasm is 1
Ω
cm and the extracellular resis-
/cm. The time constant of the cell axoplasm is 1 ms. What is the
characteristic length of the cell and what is the capacitance of the cell mem-
brane per unit area?
10.22 The key to improving the clinical outcomes of gene therapy is optimizing
the parameters involved in gene delivery, intracellular degradation and ex-
pression. For this purpose, Banks at al. [4] utilized a multiple compartmental
model (one for the cytoplasm, one for the nucleus, and one for the extracel-
lular volume) to understand the degradation kinetics and distribution of the
tance is 3
Ω
