Respiratory tract 3-compartment model

Respiratory Tract Clearance. This portion of the model identifies the principal clearance pathways within the respiratory tract. The model was developed to predict the retention of various radioactive materials. Figure 3-4 presents the compartmental model and is linked to the deposition model (see Figure 3-2) and to reference values presented in Table 3-5. This table provides clearance rates, expressed as a fraction per day and also as half-time (Part A), and deposition fractions (Part B) for each compartment for insoluble... 

Respiratory Tract Compartments in Which Particles May be Deposited 3-6. Reaction of Gases or Vapors at Various Levels of the Gas-Blood Interface 3-7. Compartment Model to Represent Time-Dependent Particle Transport in the Respiratory Tract... 

Like the lEUBK and O Haherty models, Leggett considered the lung and the GI tract as the principal sites of Pb deposition for purposes of calculating intake. Dermal deposition and uptake were taken to be minor and not modeled. The respiratory tract is modeled as four compartments where Pb... 

Compartment Model to Represent Time-Dependent Particle Transport in the Respiratory Tract... 

Leggett (1992) also proposed a respiratory tract model. Deposition of americium particles, depending on their size, are assumed to deposit in three compartments representing extrathoracic, fast-clearing thoracic, and slow-clearing thoracic regions of the respiratory tract (Figure 3-8). 

Fig. 6.8. Compartment model representing time-dependent particle transport from each respiratory tract region in the new ICRP model. The rates are in units of reciprocal days.

Figure 3 Compartment model of the respiratory tract. (Reproduced from Witorsch P and Spagnolo S (eds.) (1994) Air Pollution and Lung Disease in Adults, 1st edn., p. 22. Boca Raton, FL CRC Press, with permission from CRC Press.)...

The tissue compartments included in the Shyr model are as follows respiratory tract liver gastrointestinal tract fat and a group of richly perfused tissues including kidney, bone marrow, and heart. Muscle and skin were separated into individual compartments to allow for the simulation of dermal exposure. The distribution of 2-butoxyethanol among compartments was assumed to be limited only by blood flow rate because the lipid solubility of 2-butoxyethanol allowed it to penetrate cell membranes rapidly. Liver was a major site of metabolism in the Shyr model with a minor amount of 2-butoxyethanol-glucuronide formed in the skin at the site of application for dermal exposure. 

Table 3-9. Reference Values of Parameters for the Compartment Model to Represent Time-dependent Particle Transport from the Human Respiratory Tract (continued)...

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