PHSI 208 Lecture Notes - Lecture 3: Infant Respiratory Distress Syndrome, Alveolar Cells, Pulmonary Compliance
Document Summary
Inspiration (steps: diaphragm and inspiratory intercostals contract, thorax expands, pip becomes more subatmospheric, lungs expand, palv becomes subatmospheric, air flows into alveoli. Expiration (steps: diaphragm and inspiratory intercostals stop contracting, chest wall recoils inward, pip moves back toward preinspiration value, lungs recoil toward preinspiration size, air in alveoli becomes compressed, palv becomes greater than patm, air flows out of lungs. Lung compliance: the degree of lung expansion at any time is proportional to the change in pressure. The amount of any given change in p expands the lungs depends on the stretchability or compliance of the lungs. The reciprocal of compliance, lung elastance or elastic recoil is the ability to resist being deformed. Pulmonary fibrosis is the formation or development of excess fibrous connective tissue in the lungs. Emphysema is when proteolytic enzymes secreted by leukocytes (neutrophils) attack alveolar tissue.
