Branching pattern of airways and air spaces of a single human terminal bronchiole

Hansen, J. E.; Ampaya, E. P.; Bryant, Gillian; Navin, James J.

doi:10.1152/jappl.1975.38.6.983

Cited by 81 publications

(26 citation statements)

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“…Figure 1 shows how such polyhedra can be assembled into a space-filling acinar ductal tree. The structure of the tree is a 3D version of the schematic acinar model constructed by Fung [13], which bears resemblance with the description of Hansen et al [14]. The acinar branching tree ( fig.…”

Section: Space-filling Geometrymentioning

confidence: 89%

CFD investigation of respiratory flows in a space-filling pulmonary acinus model

Sznitman¹,

Schmuki²,

Sutter³

et al. 2007

Modelling in Medicine and Biology VII

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Due to the sub-millimetre dimensions and accessibility of the distal regions of the lung, respiratory flows in the pulmonary acinus are often difficult to assess. However, a realistic description of acinar flows is needed to understand aerosol transport and deposition for medical applications such as aerosol inhalation. In an effort to develop more realistic computational fluid dynamics (CFD) models of the pulmonary acinus, we have simulated convective flows under rhythmic breathing motion in a space-filling model of an acinar branching tree. Our model captures well the variety of 3D flow patterns present along the tree and confirms the existence of complex recirculating alveolar flows. Our results emphasize the role of the alveolar to ductal flow ratio in characterizing acinar flows. Lagrangian particle trajectories suggest that massless particles, not influenced by sedimentation or diffusion, stay principally confined within acinar ducts without entering into alveoli. The inherent modularity of the present model is well suited to create more complete geometries of acinar trees and investigate the influence of convective acinar flows on realistic sedimenting and/or diffusing particles.

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Section: Space-filling Geometrymentioning

confidence: 89%

CFD investigation of respiratory flows in a space-filling pulmonary acinus model

Sznitman¹,

Schmuki²,

Sutter³

et al. 2007

Modelling in Medicine and Biology VII

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“…Kitaoka et al [17] used a four-dimensional alveolar model, corresponding to elastin fibers at alveolar mouths and junctions of alveolar septa to simulate alveolar deformation. Hansen et al [18] studied different airway branching patterns and air spaces of a single human terminal bronchiole. Kumar et al [19] considered honeycomb shapes for acinar geometries to investigate particle transport in these regions.…”

Section: Geometrymentioning

confidence: 99%

Investigation of the Effects of Emphysema and Influenza on Alveolar Sacs Closure through CFD Simulation

Aghasafari¹,

Ibrahim²,

Pidaparti³

2016

JBiSE

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Emphysema and influenza directly affect alveolar sacs and cause problems in lung performance during the breathing cycle. In this study, the effects of Emphysema and Influenza on alveolar sac's air flow characteristics are investigated through Computational Fluid Dynamics (CFD) simulation. Both normal and Emphysemic alveolar sac models with varying collapsed volumes resulting from influenza virus replication were developed. Maximum, area average pressure, and wall shear stress (WSS) in collapsed and open alveolar sacs models were compared. It was found that a collapse at half of the volume at the bottom of the alveolar sacs' models would cause a decrease in average and maximum pressure values and yield higher WSS values for fluid flow during the breathing cycle. On the other hand, a quarter volume collapse at the bottom and side of the model resulted in higher values for average and maximum pressure and WSS. Additionally, results also showed that a combination of alveolar sacs closure and Emphysema would generally lead to an increase in fluid pressure and average WSS during breathing. Maximum WSS was observed during exhalation and maximum WSS decrease occurred during inhalation. Findings are in good agreement with previous studies and suggest that emphysema and influenza virus affect fluid flow and may contribute to alveolar sac closure. However, more realistic simulations should include the fluid-solid interaction studies.

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“…Fun-damental understanding of aerodynamic behavior of aerosolized particles suggests significant impact of alveolar geometries and airflow on particle deposition in this region. An earlier report (63) described the 3/4 spheroid as being the most common shape of an alveoli among a number of other proposed shapes. Furthermore, the 3D structure of acinar airways has been also modeled in different ways such as polyhedron models (149), full or partial annular rings representing alveoli surrounding cylindrical models (38,154), and more interesting honeycomb-like polygonal models (88).…”

Section: In Silico Lung Modelingmentioning

confidence: 99%

Computational and bioengineered lungs as alternatives to whole animal, isolated organ, and cell-based lung models

Patel

Gauvin

Absar

et al. 2012

American Journal of Physiology-Lung Cellular and Molecular Phys

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Development of lung models for testing a drug substance or delivery system has been an intensive area of research. However, a model that mimics physiological and anatomical features of human lungs is yet to be established. Although in vitro lung models, developed and fine-tuned over the past few decades, were instrumental for the development of many commercially available drugs, they are suboptimal in reproducing the physiological microenvironment and complex anatomy of human lungs. Similarly, intersubject variability and high costs have been major limitations of using animals in the development and discovery of drugs used in the treatment of respiratory disorders. To address the complexity and limitations associated with in vivo and in vitro models, attempts have been made to develop in silico and tissue-engineered lung models that allow incorporation of various mechanical and biological factors that are otherwise difficult to reproduce in conventional cell or organ-based systems. The in silico models utilize the information obtained from in vitro and in vivo models and apply computational algorithms to incorporate multiple physiological parameters that can affect drug deposition, distribution, and disposition upon administration via the lungs. Bioengineered lungs, on the other hand, exhibit significant promise due to recent advances in stem or progenitor cell technologies. However, bioengineered approaches have met with limited success in terms of development of various components of the human respiratory system. In this review, we summarize the approaches used and advancements made toward the development of in silico and tissue-engineered lung models and discuss potential challenges associated with the development and efficacy of these models. bioengineered lung; computational modeling; in silico; lung models; tissue engineering LUNG DISEASES ARE THE THIRD leading cause of deaths in the United States that translate into one in six deaths. More than 400,000 Americans die of lung disease every year and around 35 million are now living with chronic lung problems (1). Therefore, there is an important need to understand as to how a new drug entity or a novel formulation may influence the anatomy, physiology, and pathogenesis of lungs and vice versa.The human lung has an approximate volume of six liters, contains about 300 million alveoli, and provides a total surface area of 100 square meters as blood-air interface, which is packed into an elastic dynamic structure responsible for gas exchange (159). The human airway wall is a connective tissue that includes smooth muscle cells (SMC), mucus glands, blood vessels, and fibroblasts surrounded by a collagen-rich extracellular matrix (ECM). Epithelial cells, responsible for the efficient oxygen and carbon dioxide transfer, are at the interface between air and the connective tissue and are attached to an underlying basement membrane. The respiratory system is the site of a variety of pulmonary diseases such as asthma, bronchitis, pneumonia, cystic fibrosis, emphysema, a...

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Branching pattern of airways and air spaces of a single human terminal bronchiole

Cited by 81 publications

References 0 publications

CFD investigation of respiratory flows in a space-filling pulmonary acinus model

CFD investigation of respiratory flows in a space-filling pulmonary acinus model

Investigation of the Effects of Emphysema and Influenza on Alveolar Sacs Closure through CFD Simulation

Computational and bioengineered lungs as alternatives to whole animal, isolated organ, and cell-based lung models

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