Lab 6 - Lab 6 1. Draw a diagram of a spirogram indicating...

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Lab 6 1. Draw a diagram of a spirogram indicating the TV, IRV, ERV, RV, VC, & TLC. Define each of these lung volumes and capacities. Describe the mechanics of inspiration, expiration, forced inspiration and forced expiration (and relate these activities to the previously mentioned lung volumes). Explain why air enters the lungs during inspiration and exits the lungs during expiration. Tidal Volume (TV)– volume of one normal breath in and out Inspiratory Reserve Volume (IRV) – volume coming in from a forced inhalation Expiratory Reserve Volume (ERV) – volume coming out from a forced exhalation Residual Volume (RV) – volume left in lungs after forced exhalation; air that cannot come out Vital Capacity (VC) – IRV + ERV + TV Total Lung Capacity (TLC) – VC + RV Inspiration from contraction of inspiratory muscles (diaphragm and intercostals muscles) stimulated by the phrenic nerve. Contraction increases thoracic cavity and lung volume (visceral and parietal pleura are membranes pulled by the diaphragm), thereby decreasing pressure in lungs (-10mmg) lower than atmospheric pressure (0mmHg). Thus, air flows inward from 0 -10 (high to low) because of pressure gradient. Expiration from passive relaxation of above said muscles decreases the volume of the thoracic cavity and lungs (-10 -4), thereby increasing pressure and pushing air out across the pressure gradient. Inspiration and Expiration lead to breathing of Tidal Volume (TV). Forced inhalation caused by contraction of a more forceful contraction of inspiratory muscles as well as contraction of accessory inspiratory muscles = inhalation of IRV Forced exhalation caused by contraction of expiratory muscles of the abdominal wall = exhalation of ERV 2. Let’s say you sat at the bottom of a 10-foot deep swimming pool and attempted to breathe through an 11-foot snorkel. Will you be able to effectively ventilate? To answer this, you should define (a) alveolar ventilation, (b) pulmonary ventilation and (c) dead space. When examining ventilation efficiency, what parameter should be examined (a vs. b.)? Why? No, you will not be able to effectively ventilate. The pipe has too long of a dead space for the swimmer to get clean air each time. Also, the air in the pipe would not have enough atmospheric pressure to generate a gradient with the lungs. Pulmonary ventilation is the air moving in and out of the lungs and pulmonary system. However,
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This note was uploaded on 03/01/2010 for the course NPB101L 83009 taught by Professor Liets during the Spring '09 term at UC Davis.

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Lab 6 - Lab 6 1. Draw a diagram of a spirogram indicating...

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