6. Head airway (HA) Air and aerosol enter from HA Use to remove dust and other particles from entering the respiratory Humidify the air before entering the lung Separate out food to digestive system Tracheaobronchial (TB) Trachea direct air into the lung Bronchial tree is the first part of the lung. This part directs air in the lung Each branch in the tree split into 2 part Lung Regions Mouth Pharynx Larynx Nose Bronchial Tree Trachea Parent Branch Major daughter Minor daughter Bifurcation
7. Alveolar or Pulmonary (AV) Alveoli are located at the end of the bronchial tree Gas exchange occur at the Alveoli If particle deposit in this region it can directly enter the blood stream alveoli Alveolar duct Alveolar entrance rings 100µm Alveoli
10. Diffusion Cause by Brownian motion Diffusion is the deposition mechanism for small particles. Diffusion depends increases with decreasing particle size and flow rate. More deposition occurs in the alveoli region because longer residence time and smaller airway.
11.
12. Impaction Particle cannot follow the trajectory due to its inertia and hit the wall called impaction. Impaction increases with particle size and flow rate. This type of deposition occur through out the lung. This is important, especially in the head airway where most of the large particles are screened out Impaction occurs mostly in the upper generation airways due to high velocity
13.
14.
15.
16.
17.
18. Raabe Lung Model Made in 1976 by the Lovelace foundation The lung’s airways are asymmetric making the model more realistic but difficult to model Lung is divided into 5 area: Right Upper Right Middle Right Lower Left Upper Left Lower Structure of the lung was taken from replica of human lung casts.
23. Human Experiment (contd.) Deposition Fraction Dosage Rate A – Activity V min – 1 Minute Ventilation C – Concentration This experimental method is very common in pulmonary drug studies To see how much drug would be deposit when administrated. Unless the aerosol particle emits radiation, this method does not give any information about where particles are deposited. The radioactive aerosol can be scanned for regional deposition location using PET* scan Ultrafine Particle Deposition in Subjects with Asthma
27. Inhalation Fraction Original aerosol Aerosol inhale Inhaling Inhalation fraction is the ratio on aerosol inhaled to the total aerosol in the airflow. This is affected by the entry point, the orientation of the flow to the entry point, the flow rate and particle size. IF is usually presented as orientation average IF =
33. Air flow governing equations: Continuity equation Momentum equation Turbulence kinetic energy equation CFPD Pseudo-vorticity equation Particle transport equations: Slip collection factor Reynolds number Particle trajectory equation
34. CFPD The equations are solved using commercially available program CFX4.4 is used by Zhang et. al Need to set up algorithm and other parameters before the program can be run Outputs: Time, position, velocity of each particles at the end of each iteration Run simulation Time it take to run will depend on processing power and the simulation parameter Air Flow Equations Particle Equations Lung Model
39. Inspiratory spatial deposition patterns of 1 nm particles, representing unattached radon progeny in a symmetric idealized bronchial airway bifurcation (generations 3-4) for 10 3 randomly selected particle trajectories. The inspiratory flow rate of 4 L/min corresponds to a respiratory minute volume of 30 L/min.
40. Bronchial deposition fraction under resting breathing conditions (V T = 1000 mL, t = 4s) as a function of particle diameter using different scaling procedures
41. Deposition patterns of 10 nm particles under sedentary breathing conditions (V T = 500 mL, t = 4s) for five sets of diffusion deposition equations. Deposition is normalized to the number of particles entering the trachea.
42.
43.
44.
Editor's Notes
Pharynx is the tube leading air and food down from the mouth/nose to the throat. Pharynx also separate food into the digestive system. Larynx is the voice box and also help to prevent food from entering the lung.
The flow in the alveolar is much lower than in bronchial so there will be more residence time
Most flow in lung are turbulence due to the larynx and bifurcation TV – amount of air breath in and out FVC – amount of air that can be force out of the lung after maximum inspiration, this is depended on speed TLC – amount of air in the lung after maximum inspiration RV – amount of air in the lung after maximum exhalation FRC - amount of air in the lung after exhaling TV
Type - healthy, smoker, cancer Species – rat, pig, humman
AMD activity median diameter
DF total is not the same as the sum of all DF, but the result is close to it except in the submicron region
Various Zhang paper on oral airway deposition
I, j = 1 2 3 u = velocity vector X = coordinate V kinematic viscosity Tau = stress tensor K = turbulence kinetic en W = discipation per unit of k Vorticity is the measure of rotatation in fluid flow
CFX4.4 is a computer software for particle simulation. Other software also exist such as fluent.
![Contents ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)