Anatomy of the Respiratory System - An Overview - Biology, Anatomy, and Physiology

Hey guys it's Medicosis perfectionalis where  medicine makes perfect sense. Let's continue our biology playlist. We have just finished the  endocrine biology.

Today, we'll start respiratory system biology and here is a brief discussion of  the anatomy of the respiratory system. This is my biology playlist, intended for students who are  getting started, but if you are a pro there is a pulmonology playlist on my youtube channel where  you will learn about all of this nonsense. Let's start at the beginning you start here you breathe  in via your nose or your mouth regardless of the orifice that you use although i recommend you use  your nose either way you will end up here in the fairings and the pharynx is a large big tube  right here and it's divided into three pieces the part of the pharynx behind the nose is called  the nasal pharynx the part of the pharynx behind the mouth or the oral cavity is called the oral  fairings the part of the pharynx behind the larynx is called the laryngo pharynx so let's go back to  a square one we had air here we're breathing air in and then we go from nose to pharynx or mouth  to pharynx and then what and then you will go here to the laryngo pharynx and then into the larynx  which is here covered by the epiglottis down goes the trachea or the trachea and then the trachea is  gonna divide into right and left main stem bronchi here is a bronchus here is a bronchus this is  called the right main stem bronchus this is the left main stem bronchus each bronchus will give  you bronchioles the bronchioles in the beginning proximally are known as terminal bronchioles and  then when you go deeper they become respiratory bronchioles so let's do it again nose pharynx  larynx trachea bronchi bronchioles alveolar ducts and then alveoli what are the alveoli teeny tiny  sex like this what's the function two functions number one gas exchange number two secrete  surfactant what do you mean by gas exchange get oxygen into your body get carbon dioxide  away from your body why do you need a surfactant well a surfactant is anti-surface tension  surface tension wants to collapse your lungs the surfactant is anti-surface tension therefore  will prevent lung collapse so that you can breathe beautiful the lung has many functions including  to get the oxygen into your body and to remove the carbon dioxide away from your body the question is  which one is more important oh i know mitochosis of course getting oxygen in shut up getting carbon  dioxide out is way more important than getting the oxygen in how come let me explain let's say that  your oxygen saturation deteriorated and decreased from 99 percent to 94 so now your red blood cells  are carrying less oxygen what's going to happen to a real patient in real life if you decrease  from 99 to 94 oh well nothing you can survive it but carbon dioxide is responsible for the ph of  your body you know what's going to happen if the ph of your body decreased from 7.

4 to 6. 8 you're  gone you know what's going to happen if your ph increased from 7. 4 to 8.

2 well i'll need  to borrow renee's descartes philosophy and doubt your own existence carbon dioxide  influences the ph of your blood and life is only possible within a very narrow range of ph  change that was deep but this quote is not mine i borrowed it from an egyptian professor  functions of the freaking respiratory system so regulation of acid-base balance of course because  carbon dioxide is an acid how come carbon dioxide plus water will give you carbonic acid say it  again carbonic acid yeah it's an acid it can cause acidosis if you keep piling up and piling up  and accumulating carbon dioxide in your blood you get respiratory acidosis which can kill you if you  keep removing out removing out removing out carbon dioxide from the system you can get respiratory  alkalosis which can also kill you because carbon dioxide is an acid if you have more acid you have  acidosis if the acid is leaving you have alkalosis how does that happen let's say that you are  breathing less often so instead of normal you're breathing like this you're breathing less therefore you're  not removing carbon dioxide from your body therefore carbon dioxide is going to accumulate  in your body carbon dioxide is an acid you'll get respiratory acidosis which is dangerous  conversely if you're breathing too fast like this you're washing out carbon dioxide you're losing  the acid and developing alkalosis and of course you know when you have acidosis there is low  ph and when you have alkalosis there's high ph because ph is the inverse of the hydrogen ion  concentration if you remember your chemistry ph equals negative log and then here you have the  hydrogen ion concentration therefore the higher the hydrogen ion concentration the lower your ph  we call this acidosis next respiratory system is responsible for regulating your water balance  because you keep breathing in or breathing out air which includes and contains water vapor your  respiratory system is robust because it includes macrophages mast cells lysozymes these are enzymes  that cause lysis for the foreign invaders and in your nose there is iga because iga ascends  to the mucous membranes so whenever you are talking about a mucous membrane such as your mouth  your nose your larynx your pharynx they have iga iga is an antibody that's going to destroy those  foreign invaders but what if i have a disease like this mycoplasma and ammonia this is  a bacteria that can cause pneumonia why is this dangerous because this bacteria destroys your  epithelium destroys your mucous membrane including those defense mechanisms my defense mechanisms  are now toast i can get a disease next in a few minutes we'll talk about the pleura  the intrapleural pressure is negative if you have a negative pressure in your thorax  in your chest this will pull and suck blood from your feet up to your heart which will improve  the venous return from your lower extremities and back to the heart lungs contain angiotensin  converting enzyme or ace what's the function of the angiotensin converting enzyme which we have  discussed before it's to convert antigens in one to angiogens in two because it's the angiotensin  converting enzyme noda respiratory system includes the larynx which is important for vocalization  it also includes the nose which is important for olfaction at the roof of the nose there is bone  known as the ethmoid bone this bone is pierced by teeny tiny sensory fibers of the olfactory  nerve and the olfactory nerve is cranial nerve number one what's the function of the olfactory  nerve um olfaction no kidding smelling this is the sensory nerve for smell sensation it  carries impulses from your nose to your brain so that i can realize that you stink and you  need to take a shower respiratory system is also responsible for thermoregulation because you have  tons of capillaries in your respiratory system if you vasoconstrict those capillaries you  will retain heat but if your vasodilate you will evaporate and dissipate the heat why  does your nose turn blue in harsh winter nights it's because of severe vasoconstriction in your  nose because your body is trying to retain heat otherwise you will die from hypothermia we have  two types of respiration external respiration and internal respiration when you breathe in  and breathe out like this inhalation exhalation inspiration expiration you're doing external  respiration or external breathing you also have internal breathing or cellular respiration this is  the story of your mitochondria with its tca cycle and electron transport chain to make what to get  atp do you remember glycolysis tca cycle electron transport chain yeah basically you were burning  glucose in the presence of oxygen and getting energy while releasing carbon dioxide where will  that carbon dioxide go well you will exhale it respiratory tract can be divided into upper  respiratory tract and lower respiratory tract upper nose or mouth pharynx larynx and then the  lower includes the trachea bronchial tree which includes the trachea bronchi and bronchules  and then the alveoli sorry about the typo there is another functional classification  conducting zone versus respiratory zone conducting zone starts at the tip of your nose  ends in the terminal bronchioles remember we went trachea bronchi terminal bronchioles how about the  respiratory bronchioles no this these will come later and they are part of the respiratory zone  so when you are superficial near your nose this is conducting zone as you go deeper and deeper and  deeper toward your alveoli this is respiratory zone the conducting zone there is no gas exchange  but in the respiratory zone there is gas exchange because there is alveoli so what's the function  of the conducting zone well it has mucus it has the escalator to get all of the debris out of  your body it has some macrophages it has iga lysozymes for foreign invaders etc but what's  the functional respiratory zone two functions number one gas exchange number two give me the  surfactant why do you need gas exchange to get the oxygen in and get the carbon dioxide out which  one is more important getting the carbon dioxide out is more important because we're talking about  the ph here carbon dioxide is a freaking acid why do you need surfactant because it's anti  surface tension surface tension wants your lung to collapse surfactant is gonna keep your lungs  open a sneaky question that can sneak upon you on the exam they will ask you you see this right main  stem bronchus and this left mainstream bronchus yeah is there a difference oh yeah there is a  difference the right bronchus is shorter wider and more vertical the right one is more like this  more vertical but the left one is more like this more horizontal therefore if i'm a bacteria  trying to sneak into your lungs of course it's easier for me to go to the right lung than  the left lung because it's called gravity baby if i inhaled a peanut same thing it's easier  for the peanut to end up in your right lung than the left lung oh by the way if you haven't  noticed already your right is the patient left and your left is the patient right we're talking  here about a person looking at you dead in the eyes the lungs are encased by a beautiful chest  wall which includes bones muscles and joints the bones are the ribs the sternum the clavicle and  the vertebrae the muscles are intercostal muscles by the way during normal quiet breathing  you only need muscles during inspiration but you do not need muscles during expiration  because it's a passive process inhalation active needs muscles exhalation passive no muscles need  we're talking about the quiet breathing but if you're running from a tiger it's a different  story what's the most important respiratory muscle the diaphragm can i live with just a half yes  you can if mitochosis has helped you last year please consider buying me a coffee at buy me a  coffee dot com slash medicosis thank you so much for your support look at this you see this this is  the right lung and this is the left lung how many lobes are in the right lung here is a lobe here is  a lobe here is a lobe so the right lung has three pieces each one is known as a lobe this is the  upper lobe middle lobe and guess what lower lobe why is it so small like this well it is small if  you are looking from the front of the patient but it's going to continue at the back of the lung  so it's not that short look at the left lung only two lobes upper lobe lower lobe why do we  have three lobes in one lung and two lobes and the other lung because you have to account for the  heart the heart is a central structure with the apex going slightly towards the left so the heart  is huge it's taking a chunk from the left lung and that's why the left lung only has two lobes  what's the equivalent of the right middle lobe on the left side it's a teeny tiny piece  called the lingula what are these these are your lungs what's that that's the diaphragm during  inspiration it contracts and descends downwards this will expand your lungs so that you can get  the air in during expiration it's gonna relax and move upwards and therefore you're  gonna empty your lungs and get the air out the lungs are surrounded by the pleura the pleura  is a very thin cover that surrounds the lung one for the left lung one for the right lung  the pleura is made of two layers an inner layer hugging the lung is called the visceral pleura  an outer layer away from the lung but closer to the chest wall the bones and muscles here and it's  called the parietal pleura all right between the visceral pleura and the parietal pleura there is  a very teeny tiny space filled with a thin layer of fluid known as the pleural fluid this is a  very thin layer like a drop between two glass slides that you see in the lab that you use under  the microscope oh by the way these notes these slides that you see right now are downloadable  at 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