My letter to the Skeptics and the Snot-Nosed, Abhorrent Humans of this World.

My letter to the Skeptics and the Snot-Nosed, Abhorrent Humans of this World.

“How do you tell if something's alive? You check for breathing.”

― Markus Zusak, The Book Thief

            It’s the simple element of life. Things breathe to live. I don’t care if you can hold your breath for three minutes; if you want to stay alive you got to get that air into your lungs. I don’t think the universe cares that you think you’re the coolest fish ever and don’t need any oxygen; it’ll kill you if you decide not to breath. Donkeys, cats, dolphins, zebras, rodents, humans, and dromedaries all need that life-giving gas in their bodies. But some cynics and obnoxious people might question “Why?” or maybe even a “How?” Well if you promise not to ask me too many questions, I might just go over all this with you.

            To get a basic understanding of all of this, we need to know the body parts associated with this amazing system.

·         The nasal cavity is the lumpy part of your face that gets broken if you fall on your face. It’s also the only external part of the whole respiratory system. This is where air gets inhaled, filtered, and humidified.

·         The oral cavity is the secondary point that the air will enter through in the respiratory system.

·         The pharynx is the “muscular membranous channel connecting the nasal cavity to the larynx and the oral cavity to the esophagus; it enables breathing, ingestion of food and speech.” (Merriam-Webster dictionary).

·         The larynx, in simplest terms, is the voice box. It’s pretty much just a tube made with cartilage rings. Without it, you might swallow your air and breathe in your delicious tuna sandwich.

·         The trachea is between the larynx and the bronchia. It’s the continuation of the larynx that splits into two main bronchi, each leading to a different lung, and permits air to pass.

·         The bronchi are either of the two main branches that had split from the trachea. Coming from the Greek word brónchos, meaning windpipe.

·         The lungs are the main respiratory organ. It’s divided into two lobes: the right and the left. The blood gets cleaned of carbon dioxide and enriched with oxygen that came from the pulmonary artery.

·         The heart sends blood through the pulmonary artery and through the lungs to be cleansed.

·         The ribs are the bone structure that protects the lungs from any damage that might be inflicted.

To visualize the order all of these go through, here is a handy dandy picture for your studying pleasure.

Cool. So do we got all of this? There are also smaller parts of the system that we can go over when we get to them.

            So starting at the very beginning let’s say you are walking through a path that is just surrounded by dandelions. You, loving dandelions, of course, take in a huge breath of the flower’s fragrance. As it enters into your nostrils, the air gets purified of dust and dirt, and is warmed. In your nose there are lateral walls that have projections called the conchae which increase the surface area of where the air will hit. Now, on the inside of the cavity, it is lined with respiratory mucosa which will moisten the incoming air and trap the foreign particles that try to get in. On the superior surface of the cavity, there are olfactory receptors in the mucosa that will take the smell of the dandelion and tell it to the part of your brain it needs to go so it can communicate that you indeed smell a delicious dandelion.

            After the trip through the snotty part, the air travels through the pharynx. The pharynx is, for all good intentions, the throat. There are three regions of the pharynx. There’s (from superior to inferior) the nasopharynx, the oropharynx, and the laryngopharynx. The last two, the oropharynx and the laryngopharynx, are the most common passageways for food and air.

            After the pharynx, the dandelion air will enter the larynx. The larynx (being the voice box) does allow for vibrations and plays a role in speech, but also uses the epiglottis to direct the food for the ingestion by closing off the respiratory tract. The larynx routes the food and the air that come in to its proper channel. It also has the glottis which is the opening between vocal chords and the Adam’s apple which is a bunch of thyroid cartilage and the largest of the hyaline cartilage.

            The trachea is the windpipe that connects the larynx with the bronchi. The windpipe has its own form of removing dust and grossness. Its ciliated mucosa is always pushing in the opposite direction on the incoming air.

            The primary bronchi are when the trachea splits into two parts at the end and it enters the lung at the hilus. The bronchi that goes to the right lung is like the “Yao: King of the Rock” of the respiratory world. It’s wider, shorter, and straighter than the left bronchi is (who probably represents Mulan in the respiratory world, she kicks butt). The bronchi start splitting into smaller and smaller branches, the smallest of which being the bronchioles. The bronchioles have reinforcing cartilage, except for the very tiniest branches. The ending branches end in alveoli. It goes from primary bronchi, to secondary bronchi, to tertiary bronchi, to bronchiole, and ends up at terminal bronchiole.

            The lungs are covered in pulmonary (visceral) pleura. On the inside walls of the thoracic cavity parietal pleura lines the walls. And pleural fluid fills the area between layers of pleura to allow the lungs to be free and gliding. The lungs will expand when air is being put into them. Without that, then our lungs would stay at a negative pressure.

            The heart is important to the respiratory system because one of the reasons for the respiratory system is to get the oxygen back into the blood. The deoxygenated blood is being pumped through the pulmonary veins through the lungs to get the oxygen and be returned back to the heart so it could be sent out through the blood once again.

            The ribs just keep the heart and lungs and organs that are down there safe from any foul play by a wandering ninja or an unemployed Power Ranger.

            Now that we’ve been through the respiratory system, I hope you will stop being one of those specifically obnoxious people who won’t just believe when we say that it happens; and stop also needing to know “Why?” and “How”? This system will keep you alive in the darkest days. Until one day it doesn’t. And then you’re dead. But keep breathing and stay alive. Markus Zusak was a very smart man.