Please enable JavaScript.

Coggle requires JavaScript to display documents.

Respiratory (Factors that affect Pulmonary Ventilation; (Surface tension…

- - - - Inspiratory muscles relax (diaphragm moves up and becomes rounded again & external intercostals allow ribs and sternum to descend)
        
        Thoracic cavity volume decreases (because of relaxing muscles and stroma)
        
        Intrapulmonary volume decreases
        
        Intrapulmonary pressure increases (and is now higher than atmospheric)
        
        Anytime intrapulmonary pressure is higher than atmospheric pressure, air moves down its pressure gradient and out of the lungs (this continues until intrapulmonary & atmospheric pressure equalize)
  - - - Inspiratory muscles contract (diaphragm moves down, and flattens out & external intercostals lifts rib cage [out & up] and pulls sternum superiorly)
        
        Thoracic volume increases (intrapulmonary volume increases)
        
        Intrapulmonary pressure decreases
        
        Anytime intrapulmonary pressure is lower than atmospheric pressure, air moves down pressure gradient and into lungs. Inspiration continues until intrapulmonary & atmospheric pressure equalize
- - - - Type II alveolar cells- simple cuboidal epithelial cells that are spaced at irregualr intervales in the alveolar walls- each produce surfactant (reduces the surface tension of alveolar fluid to prevent collapse during expiration) that coats the alveolar surface
        
        also secrete antimicrobial agents that function in innate immunity
      - Alveolar macrophages- a population of fixed macrophages that continually move over the alveolar surface to remove cell debris and pathogens (create sterility in healthy people)
      - Typle I alveolar cells- make up the majority of the alveolar wall- special type of simple squamous epithelium
    - - Each contains 3 layers; type 1 cell of alveolar wall, endothelium of the pulmonary capillary, & the fused basement membranes of these two epithelia