This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: pressure- intrapulmonary (intra-alveolar) pressure (P alv ) : pressure within alveoli of lungs o rises & falls with breathing, but always equalizes with P atm- intrapleural pressure (P ip ) : pressure within pleural cavity o also varies with breathing, but is always about 4 mm Hg less than P alv (negative with respect to both intrapulmonary & atmospheric pressures) o 2 forces lead to lung collapse: natural tendency of lungs to recoil surface tension of alveolar fluid (draws alveoli to smallest dimension) o these forces are opposed by the elasticity of chest wall (so thoracic cavity expands, preventing lung collapse) Kevin Kelleher, MTC Biology 211 Study Notes Exam 2 17 o any condition that equalizes intrapleural pressure with intrapulmonary or atmospheric pressure can cause immediate lung collapse o transpulmonary (transpulmonic) pressure : P alv - P ip keeps lungs from collapsing PAGE5...
View Full Document
- Fall '10