WEBVTT

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the primary function of the respiratory

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system is to obtain oxygen for use by

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the body cells and to eliminate the

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carbon dioxide that these cells produce

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dr green . Can you tell us how the

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respiratory system does this well ? Dr

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Reynolds the first step in

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understanding the respiratory system is

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to take a look at the various parts in

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general . This system includes airways

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that lead into and out of the lungs and

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of course the lungs themselves . The

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lungs allow oxygen to enter the body in

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exchange for its waste product carbon

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dioxide . As the oxygen passes through

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the nose and mouth , it's rapidly

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warmed and moistened to avoid injury to

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the delicate lining of the airways .

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The nose and airways trap large

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particles like dust , pollen , molds ,

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bacteria and chemicals which could

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cause serious harm to the lungs . The

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air is then transported through the

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trachea and bronchi to smaller airways

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called bronchial walls . These airways

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have branches like a tree , so that

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millions of small airways can carry

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oxygen to tiny air sacs called alveoli .

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The airways have a delicate cellular

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lining called mucosa , which is coated

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with a thin layer of mucus . Foreign

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particles are trapped by the sticky

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mucus and removed from the airways .

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Through a cleansing process . Tiny hair

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like structures called cilia move the

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mucus and trapped foreign particles up

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toward the mouth and nose , where they

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are coughed out , sneezed out or

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swallowed bundles of muscles surround

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the airways , and the contraction of

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these muscles directs the flow of air .

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The body needs a continuous supply of

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oxygen for cellular respiration , and

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at the same time it must get rid of

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excess carbon dioxide , which is the

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poisonous waste product created in the

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body cells . Gas exchange is the

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exchange of oxygen and carbon dioxide

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between the air and the blood in the

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lungs . Blood enters the lungs through

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the pulmonary arteries . It then moves

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through arterials and into the valvular

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capillaries . Oxygen and carbon dioxide

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are exchanged between blood and the air .

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The newly oxygenated blood then flows

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back to the heart through the pulmonary

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veins so the heart can distribute

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oxygen to the rest of the body . Mhm .