Lung compliance and airway resistance 1

This set of flashcards covers key vocabulary and concepts related to lung function, compliance, and related pathologies for exam preparation.

FEV1/FVC

A test that measures lung function, indicating the ratio of forced expiration volume in one second to forced vital capacity.

Normal FEV1/FVC ratio

Approximately 80% in a normal person.

Obstructive lung disease

A condition where both FEV1 and FVC decrease, resulting in a decreased FEV1/FVC ratio.

Restrictive lung disease

A condition where both FEV1 and FVC decrease, but the FEV1/FVC ratio remains the same.

Lung compliance

The volume change produced by a unit change in transmural pressure.

Resistance to airflow

The opposition to the flow of air in the lungs, affecting ventilation.

Surface tension in alveoli

The force that exists at the water-air interface, impacting lung expansion.

Pulmonary surfactant

A mixture of phospholipids and proteins that reduce surface tension in the alveoli.

DPPC

Dipalmitoylphosphatidylcholine, the main component of pulmonary surfactant.

Hysteresis

The difference in lung compliance during inflation and deflation due to surface tension.

Reynold's number

A dimensionless number used to predict flow patterns in different fluid flow situations.

Dynamic lung P-V curve

A graph that illustrates the relationship between lung pressure and volume during breathing.

Airway resistance

The resistance to airflow within the respiratory passages.

Turbulent flow

A flow regime characterized by chaotic changes in pressure and velocity, typically in larger airways.

Laminar flow

A smooth, orderly flow of air in small airways.

Chronic Bronchitis

A condition characterized by chronic inflammation and mucus production in the bronchi.

Asthma

A chronic disease causing inflammation and narrowing of the airways, leading to difficulty breathing.

Emphysema

A condition characterized by the destruction of alveolar walls, resulting in decreased elastic recoil and increased airway resistance.

Pulmonary Fibrosis

A lung disease that occurs when lung tissue becomes damaged and scarred, reducing compliance.

Respiratory Distress Syndrome (RDS)

A syndrome often seen in premature infants due to the lack of surfactant, leading to difficulty breathing.

Compliance decreases at larger lung volumes

As lung volume increases, lung compliance generally decreases.

Transpulmonary pressure

The pressure difference between the inside of the alveoli and the pleural space.

Laplace's law

A law describing the pressure inside a alveolus, P = 2T/r, balancing the surface tension and radius.

Recoil of lungs

The tendency of the lungs to return to their resting state after being inflated.

Surface tension's effect on lung function

Essentially reduces lung compliance by increasing the effort required to expand lung tissue.

Pulmonary surfactant's role in alveoli

It reduces surface tension, allowing smaller alveoli to remain stable and preventing collapse.

Factors affecting airway resistance

Includes smooth muscle contraction, thickened airway walls, mucus secretion, and lung tissue destruction.

Lung compliance summary

Determined by surface tension and stretchability of connective tissues.

Pulmonary edema

The accumulation of fluid in the alveoli, leading to decreased lung compliance.

Conductive zone

The part of the respiratory system that includes the trachea and branches, responsible for air passage.

Static lung compliance

Particular compliance measured at a fixed lung volume without airflow.

Dynamic lung compliance

Compliance assessed during changing lung volumes and airflow.

Intrinsic factors affecting lung compliance

Such as age, gender, and body composition.

Pulmonary diseases affecting compliance

Restrictive diseases lead to low compliance, while obstructive diseases cause high resistance.

Frictional resistance

The resistance encountered from air movement against the walls of the airway.

Lung volume and resistance correlation

Higher lung volume generally lowers airway resistance.

Mucosal edema

Swelling in the airway walls that increases resistance.

Compliance decreases with thicker lung tissues

Thickening of lung tissues leads to lower lung compliance.

Surfactant recruitment

The process of surfactant accumulating at the alveolar surface when the lung is inflated.

Influence of age on lung function

Lung mechanics parameters vary based on the individual's age.

Pulmonary function testing

Assessing lung function using metrics like FEV1, FVC, and compliance.

COPD

Chronic obstructive pulmonary disease, a combination of emphysema and chronic bronchitis.

Airway remodeling in asthma

Structural changes in the airways due to chronic inflammation.

Impact of lung compliance on ventilation

High compliance allows for easier breathing and lung expansion.

Mechanism of surface tension reduction

Surface active agents lower the surface tension, contributing to better lung function.

Transitional flow characteristics

Flow in airways that is a mixture of laminar and turbulent flow.

Lung volume control mechanisms

Controlled by the interplay of surfactant, airway resistance, and elastic recoil.

Cohesive forces in alveoli

Stronger forces among water molecules create surface tension that must be overcome for lung inflation.

Pulmonary surfactant composition

60% DPPC, 20% other phospholipids, and various proteins.

Importance of surfactant in newborns

Lack of surfactant leads to respiratory distress syndrome in premature infants.

Pulmonary testing parameters

Involves measuring lung volumes, capacities, and flow rates to assess function.