9.19 If you model the breathing airway as a series of sequential passages,the na
ID: 3166316 • Letter: 9
Question
9.19 If you model the breathing airway as a series of sequential passages,the nasal or mouth passage, the pharynx, larynx, and then trachea, each with a resistance to air flow, what is the total resistance to air flow in terms of these individual resistances?
Heres some info. But I need to know in terms of INDIVIDUAL RESISTANCES. So please answer it interms of that.
Let us say that the inflow of air per breath is Vin. Then the average flow rate is Qav-Vin/ Thalf period. For Vin = 0.5 L, this is 0.25L/s. If the flow rate is proportional to the pressure drop, Q and ?? have the same dependence on time and so Qmax-(n/2)Qav , which is (n/2)0.25L/s = 0.4 L/s, and Q(t) = Qmax sin(2nft) Qmax sin(nt/Thalf period). Moreover, Q-AP/Rflow , where Rflow is the total resistance to flow in the nasal passages, trachea, and so on. The resistance to flow is Rflow-AP/Q, and so using average values we see that Rflow = 0.7 mmHg/(0.25 L/s) = 3.7 x 105 Pa-s/m3Explanation / Answer
Resistances of the nasal and pharyngeal segments in Pa/cm3 per second averaged 0.139 (SD +/- 0.044) and 0.081 (SD +/- 0.051), respectively. There is no other evidences for the resistance that is in agreement with the airflow pressures. In terms of laryngeal segment, it shows reciprocal of compliance, expiratory resistances exceeded those of inspiration, averaging 0.125 (SD +/- 0.037) and 0.035 (SD +/- 0.013), respectively. On the other hand the Tracheobronchial resistances at the time of spontaneous resting breathing were too small to record reliably. So, Laryngeal expiratory resistance calculated about one fifth of the sum total of respiratory airflow resistances (including the pulmonary airways).
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