Related Experiment Video
Updated: May 31, 2026
11:10
Micro-Mechanical Characterization of Lung Tissue Using Atomic Force Microscopy
Published on: August 28, 2011
Hypo-elastic model for lung parenchyma
Alan D Freed1, Daniel R Einstein
1Department of Mechanical Engineering, Saginaw Valley State University, 202 Pioneer Hall, 7400 Bay Road, University Center, MI 48710, USA. adfreed@svsu.edu
Biomechanics and Modeling in Mechanobiology
|July 12, 2011
Summary
This study presents a simple, isotropic, elastic model for lung spongy tissue, demonstrating that observed pressure-dependent behavior is due to non-linearity, not anisotropy. Model predictions align with experimental data for dog lungs.
Area of Science:
- Biomechanics
- Materials Science
- Pulmonary Physiology
Background:
- Lung spongy tissue exhibits complex mechanical behavior.
- Previous interpretations suggested extensional anisotropy in lung tissue.
- Hypo-elasticity offers a framework for modeling non-linear elastic materials.
Purpose of the Study:
- To formulate a simple, isotropic, elastic constitutive model for lung spongy tissue using hypo-elasticity.
- To investigate the origin of pressure-dependent behavior in lung tissue.
- To compare model predictions with experimental data for validation.
Main Methods:
- Formulation of an isotropic, elastic constitutive model based on hypo-elasticity theory.
- Analytical determination of model response for various boundary value problems.
- Comparison of model predictions with published experimental data for dog lung.
Main Results:
- The isotropic hypo-elastic model naturally exhibits pressure-dependent behavior.
- This behavior is attributed to material non-linearity, not inherent anisotropy.
- Model predictions show good agreement with experimental data for dog lung.
Conclusions:
- The proposed isotropic hypo-elastic model accurately captures lung spongy tissue mechanics.
- Pressure-dependent behavior in lung tissue is a consequence of non-linearity.
- The model provides insights into material behavior and parameter bounds.
Related Concept Videos
01:24Pressure Relationships in Thoracic Cavity
Breathing, otherwise known as pulmonary ventilation, is the process of air movement into and out of the lungs. The main mechanisms propelling pulmonary ventilation are atmospheric pressure (Patm), intra-pulmonary (Ppul ) or intra-alveolar pressure (Palv) within the alveoli, and intrapleural pressure (Pip) within the pleural cavity.
Breathing Mechanisms
Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs during...
Breathing Mechanisms
Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs during...
01:23Chronic Obstructive Pulmonary Disease II: Emphysema
Emphysema, a major phenotype of chronic obstructive pulmonary disease (COPD), is characterized by irreversible destruction of alveolar walls and permanent enlargement of distal airspaces. Unlike chronic bronchitis, which primarily affects the airways, emphysema predominantly involves the lung parenchyma, where structural damage leads to airflow limitation.PathophysiologyIt most commonly results from prolonged exposure to cigarette smoke and other toxic gases, particularly cigarette smoke.
01:19Factors Affecting Pulmonary Ventilation
Besides the pressure difference between the external environment and the lungs, the airflow rate and ease of pulmonary ventilation are also influenced by three other factors: surface tension of the fluid in the alveoli, compliance of the lungs, and airway resistance.
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
01:12Elastin is Responsible for Tissue Elasticity
Elastic fiber contains the protein elastin along with lesser amounts of other proteins and glycoproteins. The main property of elastin is that it will return to its original shape after being stretched or compressed. Elastic fibers are prominent in elastic tissues found in skin and the elastic ligaments of the vertebral column.
Ligaments and tendons are made of dense regular connective tissue, but in ligaments not all fibers are parallel. Dense regular elastic tissue contains elastin fibers and...
Ligaments and tendons are made of dense regular connective tissue, but in ligaments not all fibers are parallel. Dense regular elastic tissue contains elastin fibers and...
01:12Elasticity
Elasticity is the ability of an object to withstand the effects of distortion and to return to its original size and shape once the forces causing deformation are removed. When an elastic material deforms under the action of an external force, it experiences internal resistance to the deformation. However, if no external force is applied, it returns to its original state.
The elasticity of an object can be described by a stress-strain curve, which represents the relationship between stress...
The elasticity of an object can be described by a stress-strain curve, which represents the relationship between stress...
01:17Pulmonary Cycle: Exhalation
In terms of human respiration, the act of expelling air, known as exhalation (or expiration), operates on the principle of pressure gradients. During expiration, the pressure within the lungs exceeds that of the surrounding atmosphere. Under normal conditions, quiet breathing involves passive exhalation and is free of muscular contractions. This is because the exhalation process is driven by the natural elastic recoil of the lungs and chest wall, both of which have an inherent tendency to...