Breathe!

A overview of the anatomy of the human respiratory system, along with an explanation of lung ventilation. Lyrics: Welcome to system we call respiratory How we get O2 in and CO2 out is our story Because every organism, familiar or strange Has to carry out gas exchange In all larger species there’s a respiratory surface Like a gill or a lung that evolved for the purpose Of providing enough surface area for gas diffusion In four limbed species lungs are the solution CHORUS Breathe, inhale, pull the diaphragm down Let the air rush in take in oxygen Exhale, relax, let the air rush out, Feel the vocal cords vibrate when you talk or shout. Feel the air in your nose, then the the pharynx, then the glottis, then the larynx, then the trachea, then left or right bronchus To the smallest bronchioles to the alveoli Now, let the air out, breathe a happy sigh! CHORUS An oxygen molecule outside your nose Into the nasal cavity it flows Passing hairs and cells secreting mucus with each inhalation Ciliated cells that line this pathway help out with filtration Then to the back of the mouth the O2 passes, (You know the mouth’s the other pathway for inhaling gases) That’s why drinking and laughing can (as everybody knows) Send the liquid that you drank right out your nose Next the O2 starts its passage down the windpipe through the glottis Protected by a flap that’s called the epiglottis Which covers the windpipe when we swallow Makes the esophagus the only path that food can follow CHORUS So after the back of the mouth, which is also called the pharynx, Comes the top of the windpipe, the voicebox or the larynx, The trachea’s next, its many cartilage rings, Always keep it open, for the air it brings The trachea ends when it branches into two Large bronchi, also known as bronchial tubes, A branching tree forms as the tubes subdivide, Until they end in hollow sacs called alveoli Each alveolus has capillaries outside it Through which red blood cells file right by it O2 diffuses into each red blood cell Which becomes oxygenated makes it feel so swell CO2 oozes in the opposite direction Moving to the alveolus, diffusing with perfection CO2’s out; O2’s in Fill your lungs with oxygen so CHORUS Now let’s look at lung ventilation The way we power inhalation and exhalation The thoracic (chest) cavity's a sealed closed chamber That's why a chest wound carries so much danger So just below the rib cage in a woman or man Is a sheet of tissue called the diaphragm Muscles below the diaphragm can pull it down This powers ventilation let me show you how Inhalation pulls the diaphragm down which increases Chest cavity volume so the pressure decreases; The higher pressure air outside the lungs flows in The lungs inflate that's inhalation To exhale you relax, diaphragm arches up Sends chest cavity pressure up So as chest cavity volume's decreased The gases in your lungs have to be released so CHORUS