KNES 260 Study Guide - Midterm Guide: Vasodilation, Vasoconstriction, Central Chemoreceptors

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Document Summary

Type i alveolar cell: make up alveolar wall. Type ii alveolar cell: secretes surfactant to decrease surface tension. Air flows from a region of high pressure to low pressure (atmospheric air flows into alveoli: gas exchange occurs. Expiration: the external intercostal muscles and diaphragm relax (to decrease the thoracic volume) Causes the lungs to compress and decreases volume within them: the decrease in volume raises the pressure of air within the lungs. Air flows from a region of high pressure to low pressure (lung air flows into atmosphere) Pressure gradient: the difference in air pressure between the atmosphere and alveoli. Resistance: the radius of the bronchioles is the biggest determinant in air flow. Important for compliance (to expand the lungs when being stretched) Important for recoil (the lungs rebound after being stretched) Surfactant: decreases the surface tension of alveolar fluid, discourages alveolar collapse. Tidal volume: the volume of air entering or exiting the lungs during a single breath, avg.