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Structure of the Respiratory System. Alveoli and Lung Volume. Alveoli. Tiny air sacs in the lungs Where gas is exchanged Bunches at the end of bronchioles Maximize surface area for gas exchange. How do Alveoli Work?. Capillaries cover surface of alveoli Oxygen from lungs to blood
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Structure of the Respiratory System Alveoli and Lung Volume
Alveoli • Tiny air sacs in the lungs • Where gas is exchanged • Bunches at the end of bronchioles • Maximize surface area for gas exchange
How do Alveoli Work? • Capillaries cover surface of alveoli • Oxygen from lungs to blood • Carbon dioxide from blood to lungs
Surfactant • Lines inside of alveoli • Reduces surface tension of water (like soap) • Allows easier gas exchange • Keeps lungs from collapsing
Lung Capacity • Compliance – ability of a lung to expand • Low compliance makes breathing difficult • Ex: emphysema
Lung Capacity • Tidal volume – actual amount of air moved into or out of the lungs in one cycle • One cycle = inhalation and exhalation • Vital capacity – maximum amount of air that could be moved during one cycle • Residual volume – air remaining in lungs after exhalation
Lung Capacity • Inflation reflex – prevents lungs from overexpansion • Only occurs during forced breathing • Deflation reflex – prevents lungs from collapsing during exhalation