Hello everyone, my name is Bryan Lau. Today we are going to talk about the introduction of respiratory medicine. That the respiratory system, we would just focus probably on the basic logic and the basic concepts of how the respiratory system works today, and we would not go in deep in each subtopic, because we don't want to confuse you. Today, the purpose of the introductory course is to bridge you from the study of the science, probably many years ago towards our master course of sports medicine, you don't need to worry about the knowledge of today. You just need to grab the basic idea and how to think, how to logicalize all the concepts today and have fun. Today we are going to share different contents, including the basic anatomy of the respiratory system, starting from the mouth, the nostril towards the end part of the lung, we call the alveoli. We're going to talk about the breathing muscles, there are several layers of the muscles. Some are primary and some are secondary. Some are more important, and some are less important. We are going to talk about this. We will also talk about the mechanics of the respiratory system on how we use those muscles on inspiration and expiration. The major purpose of the respiratory system is for gaseous exchange, oxygen and carbon dioxide in the hemisphere and within our lungs, and how we can exchange those essential gaseous' content. We are going to talk about it by using the concept of the changes in pressure and volume in different compartments within our body and how it is related with the external environment. We will also mention a little about the effects of exercise on the respiratory system in both short-term and long-term effect. In short term, most of the changes are related with the physiological response; for long time changes, it is more about adaptation and from the changes of the anatomical structures. Finally, we will also mention about hypoxia, the cause of hypoxia. Now determine hypoxia, “hypo-“ meaning too low, “-xia” meaning oxygen. We would talk about the cause of too low of the oxygen, meaning there is not enough or inadequate oxygen within our body. The causes of them and how it relates with the common lung disease. Alright. From the beginning, I want to mention a very key concept about the respiratory system, which the system is a highly complex dynamic system, meaning it is not even stay in a static moment. It always changes from inhalation to exhalation and there is no such called the equilibrium condition during the whole dynamic process. It is always a process involving chasing the equilibrium from the non-equilibrium condition. So that's a lot of changes in terms of pressure, in terms of the volume, and it is the key factor on how the gaseous could diffuse or could be passing from one compartment towards another. Another key factor of the respiratory system, which is not just about the lung, it is always about the mutual interaction between the lung towards other influences, such as external environment. You can imagine there would be a large difference when we are going to high altitude environment or underwater environment, so these changes of the external environment will increase our challenge on how we can operate with the gaseous exchange in the respiratory system. Another factor will be the internal stimuli through the inflammation within our body. So inflammation causes swelling of the coating of the respiratory system. It will enhance the secretion of the mucus on top of the coating, so these changes through inflammation will affect the respiratory system also. So today, we are going to look at how these kinds of changes will alter our condition during respiration. Another system which is working very closely to the respiratory system is the cardiovascular system. The heart works closely to the lung in order to deliver enough oxygen towards the tissues and bring enough carbon dioxide from the tissue towards the lung, in order for an adequate gaseous exchange over the lung. So the function of the heart should work closely and work effectively with the respiratory system also. Another factor which is also common to see is the psychosocial factors. When people having stress, when they have increasing the sympathetic nervous stimuli, they will tend to have an increase in the respiratory rate. These kind of changes under the autonomic nervous system will affect the ventilation also. By all means the major function of the respiratory system is still about how it facilitates the gaseous exchange between the environment and the bloodstream. It is all about how we can deliver the oxygen from the environment towards the tissue and how we can bring the carbon dioxide from tissue towards the external environment. Now we are going to talk about the function of the respiratory systems. Oxygen should be grabbed from the environment and bring them towards bloodstream. So that's why we need a structure or anatomical structure who can facilitate it from happening. In order to bring the oxygen from the lung towards the tissue, we also need to involve the cardiovascular system. So the bloodstream, like red blood cells and hemoglobin within the bloodstream, could help us to carry the oxygen from the lung towards the tissue. We would go to talk about this also. Oxygen is necessary and essential to produce a unit called ATP, which is a basic unit of energy within human body. The most important and essential mechanism to produce ATP is through Aerobic pathway, meaning the body needs oxygen as a primary fuel to produce energy for the body to use. Like moving our body, like the function of the liver and the brain, all kinds of organs and tissue would need ATP. Oxygen itself will bring us the most effective pathway to produce this ATP. You may also learn from the others that there's another pathway called the Anaerobic pathway for production of the ATP, which is also possible. The body can produce ATP without oxygen, but in a more ineffective way. Less ATP could be produced in a short period of time, so in long term we still need oxygen to produce enough ATP for the human body use. Another thing we have to consider about the transport of the gaseous within our body would be carbon dioxide. Now carbon dioxide is a very common byproduct of our metabolism. The carbon dioxide we need to treat it as a metabolic waste and find a way to eliminate the carbon dioxide from our body effectively. If we have too much of the carbon dioxide within our body, acidosis- meaning too much of the acid within our body could happen and it will affect a lot of different organs’ function, including liver and kidneys. So that's why we need to find an effective way to get rid of it. To eliminate the carbon dioxide from the body towards the external environment, so it is another primary function of the respiratory system.
