Biomedical Engineering Reference
In-Depth Information
200
100
(i)
0
−100
200
100
(ii)
0
−100
200
100
(iii)
0
−100
200
100
(iv)
0
−100
200
100
(v)
0
−100
0
1
2
3
4
5
6
7
8
Time (s)
Fig. 10 Intraluminal pressure traces approximated using Lamé's theory of stresses within thick-
walled cylinders. Each subplot illustrates the pressures calculated at the gauss point locations
marked in Fig.
7
a)
The modeling framework proposed in this chapter consists of three main parts:
(i) geometric model; (ii) electrical model; and (iii) electromechanical model. Many
simplifications were made in order to create a computationally feasible model. For
example, a simplification applied to the model geometry is the two-layered wall
structure representing the circular and longitudinal muscle layers. This idealized
geometry ignores the effects of other anatomical layers in the small intestine.
While the missing layers do not generate active tension, they contain structural
features, such as collagen fibers, which contribute to the passive mechanical
properties of the intestinal wall. Additionally for simplicity, we assumed equal
thickness of the longitudinal and circular muscle layers, although morphometric
studies have shown that the circular muscle layer of the rat small intestine is
approximately 1.2 times thicker than the longitudinal layer [
19
]. Assuming muscle
fiber density is consistent in each layer, this unequal thickness ratio may affect the
active tension generated.
Search WWH ::
Custom Search