LING 2P90 Lecture Notes - Lecture 6: Mechanoreceptor, Pleural Effusion, External Intercostal Muscles
15 Jan 2016
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Document Summary
Passive forces, active forces, movements of rib cage, diaphgram, abdomen wall. Intra-pleural pressure: between visceral and thoracic (costal) pleurae. Transdiaphragmatic: pressure difference across the diaphragm| pdi= pab - ppl. Circumference of rib cage wall increases on inhalation. Circumference of rib cage wall decreases on exhalation. *-possible because of 2 joints: costosternal joints; costovertebral joints (costo- central + costo-transverse) Relative movements: palv (alveolar pressure) influenced by percentage contact rib cage & abdomen have with lungs. Each time we inhale (airway is open), we get an increase in lung volume. Can be partitioned into: lung volume + lung capacities. Can measure lung volume with: wet spirometer, dry spirometer, computerized spirometer, pneumotachograph. Resting expiratory level (rel): tendency of lungs to collapse vs. tendency of thorax to expand. Tidal volume (tv) -volume of air inhaled and exhaled during a breath cycle. Inspiratory reserve volume (irv) maximum volume of air that can be inhaled beyond peak of tidal inhalation.
