That big breath I just took, it took the coordination of my central nervous system, a large amount of muscles, lung tissue, negative air pressure to make that happen. In this video, we will talk about the patient, general appearance and ABC's. ABC's is the acronym for EMTs and other health care providers to organize and prioritize the order in which we need to assess our patients. While we list them in order, in real life they are being assessed simultaneously. We're going to discuss A and B in this section airway and breathing. How about a quick anatomy review, before you can understand physiology you need to be familiar with the anatomy of the organ system. Remember, there are number of parts to the airway including the mouth, nose, tongue, larynx, pharynx, the vocal cords and trachea and that's just the upper airway. So go ahead and review the module on anatomy of the respiratory system as needed. See the list in the resources section to make sure you can identify all of the parts of the airway and respiratory system that are listed. Doing so is a great way to get ready before diving into this module. The respiratory system, is the organ system of breathing and the airway system is the roadway by which we breathe. Through your airway, oxygen is taken into the lungs and carbon dioxide is expelled from the lungs. This is called gas exchange. Imagine that a shuttle is carrying passengers from a pickup point to a destination, the pickup point is at the nasal and oral pharyngeal and the passengers are waiting for a ride are the oxygen molecules. This shuttle carrying oxygen passengers is headed down deep into the lower airway of the lungs the respiratory system, to its ultimate destination the alveoli. Once it reaches the alveolus, it unloads its oxygen passengers and picks up other passengers and exchange, carbon dioxide. This shuttle and turns around and exits the lower airways headed straight for the upper airway and ultimately our nose and mouth. Where the car the shuttle says goodbye to carbon dioxide and hello to a fresh new gang of oxygen passengers. This gas exchange and the shuttle runs 24 hours a day, seven days a week for as long as our body is alive. It is also worth mentioning that these molecules get exchanged at every alveolus in the lungs with each breath. The oxygen molecules are dispersed to each of the approximately 600 million alveoli in our lungs and the carbon dioxide molecules are collected from them as well. The airway is the road which the shuttle must travel to go back and forth between the pickup points for oxygen and then pick up points for carbon dioxide and remember, if you're patient doesn't have an airway, if the roadway is blocked or broken your patient cannot survive. Now that you understand this roadway we call our airway, we will discuss the physiology of breathing called ventilation. The action of getting air into the lungs, take a deep breath in, this is called inspiration and it's how your body sucks air into your lungs to provide yourselves with oxygen. How does this happen? It takes a combination of numerous muscles coordinating and a difference in air pressure between inside our chests and the outside world. The most important muscle involved is a diaphragm, the diaphragm is a large muscle between the thoracic and abdominal cavities sitting at the bottom of our rib cage. The diaphragm is strong and when it contracts it descends into your abdomen somewhat, while simultaneously your intercostal muscles, the muscles between your ribs contract. This makes the rib cage expand grow in size and because our lungs adhere to or stick to our rib cage, due to the sticky fluid coding the outside of them called the pleura, our lungs get pulled outward and downward. Think about trying to pull on empty rubber balloon open, this creates a lower pressure in the chest rather than outside of it where our environment where the air is heavy at earth's surface. This difference in pressure inside of our thorax when the muscles contract for inspiration is called a negative pressure difference and it's like a vacuum. At this point, the heavier outside gets drawn into our lungs by the negative pressure vacuum, the active inspiration is called an active process because it requires energy to activate the muscles of breathing and create this negative pressure gradient. If our breathing muscles failed or we were not able to activate them, we will not be able to breathe air in inspire on our own. Now exhale, I'm sure you already have exhaled already because your body cannot naturally hold its breath for too long. We could talk about why a little later, but think about how inspiration is this active process. Do you think exhalation involves the same muscle work or energy? Do you think exhalation is an active process? We'll end the video here while you consider and discuss this question, to find the answer move on to the next video.
