basically there are six ways to control this process six ways that respiration is altered number one don't you love how clever I am with this little clip art that's right teacher of the year so these things that are called respiratory areas and I know they should be called something fancier right but these are found in your brain stem so remember the brain stem from a Impe one is the really old school stuff like your medulla oblongata and your pons so how is the nervous system involved from last semester we had the pons which was the little pregnant belly on the traveling seahorse smoked in a pipe with his backpack and his umbrella because he's traveling so the pons is his little pregnant belly and that stimulates the medulla oblongata which has the medullary respiratory center the phrenic nerve which is part of that cervical plexus if you remember a plexus is just a group of nerves and cervical is the group of nerves that are coming out of your neck out of your cervical vertebrae and the intercostal nerves which are the nerves between your intercostal muscles which are the rib muscles so all of this is going to excite your diaphragm and the external intercostal muscles and the abdominal muscles if needed it just depends on the depth of your breathing so the nervous system is all about controlling your breathing we want to make sure it's rhythmic we want to make sure you're not panting like a dog so we're checking for chemistry so this first one here that's in your medulla oblongata is checking for carbon dioxide and therefore those hydrogen ions because remember too much carbon dioxide getting dissolved in your blood is going to acidify your blood and raise your hydrogen ion levels so if either one of these increase you get too many hydrogen's or you get too much carbon dioxide we're gonna increase your respiratory rate and your depth so think of your normal your normal tidal volume your normal breathing you're breathing in about 10 to 15 times a minute so if you get too much carbon dioxide in your blood you're gonna step that up you're going to breathe in a lot more intensely and a lot deeper so normally you're barely moving your lungs right well you can speed that up and increase your depth change in oxygen is not affecting this area of your brain so the medulla oblongata is literally checking for carbon dioxide the pawns roll the little pregnant belly his role is the rhythm of your breathing so the pawns is what keeps you from holding your breath for a minute and then panting like a dog so number two the carotid and the aortic bodies so there are chemo receptors that are checking your chemistry in your carotid artery and in the aortic arch so these guys are checking for oxygen and this makes sense right because if I'm trying to make sure that I have enough oxygen for my entire body I'm gonna check it in the carotid which is going to my brain and in the aorta which is going to the rest of your body it's not like you're gonna want to check oxygen levels in your toes it's like that would be almost too late right so the best blood in your body the best oxygenated blood in your body is coming out of the aorta and then going to the BCS so especially that carotid the common carotid the second guy coming off your heart right so if these guys are low in oxygen you know that all the other arteries in your body are going to be low in oxygen so this will cause an increase in your respiratory rate and depth of breathing and breathing so this is your backup when oxygen is critically low what I mean by that is if you go somewhere like you're in the mountains and the oxygen level outside is very low or if you go to a lot of museums they'll keep the oxygen levels a little low because they're trying to protect the art so you'll find that when the atmospheric oxygen is low you'll kind of start panting number three the inflation reflex also called the herring Brewer reflex you have stretch receptors in your visceral pleura that lining around your lungs in the bronchioles because remember those are the microscopic tubes in your lungs that don't have cartilage and the alveoli which are the little balloons so those guys have stretch receptors to keep them from bursting and so if the stretch receptors get activated the nerve impulse is fine down that vagus nerve which if you remember from A&P one was cranial nerve number 10 will stop inspiration so this just makes sure that we don't over inflate our lungs when we're breathing really really hard especially for exercising or running from a lion Tiger bear oh my so if you remember the vagus nerve did the same thing for your heart if your heart speeds up too much the vagus nerve kind of puts the brakes on the fourth control of breathing obviously respiratory rate changes from fear from pain and from being cold so if you're scared you may go that's scary or if you're in pain you might go ooh that hurts really bad or at chill you're like oh I don't know what that was that really wasn't a chill that was very strange so all of these raise your respiratory rate and cause you to gasp right so that's changing your respiratory rate that's affecting your respiratory rate so that's number four the fifth thing that affects respiratory rate you do have some degree of conscious control over your respiration I mean you can hold your breath right you can start panting like a dog right so if you consciously can stop breathing your co2 and therefore your H pluses your hydrogen ions which makes your blood acidic will rise you can't hold your breath forever eventually your brain is screaming right to start breathing that's because the respiratory center in the medulla oblongata is measuring the carbon dioxide and now it's real pissed at you so eventually your need to inhale will override your decision not to and you'll breathe so even if you're really stubborn like I used to do this when I was a kid if I didn't get what I wanted I told my mom well fine I'll hold my breath until I die and she called me out on it once and she's like if you hold your breath until you die first of all you're not gonna die you're just gonna pass out and then you're gonna start breathing again moms always win and the sixth thing there wasn't six fingers so I just did this creative little number right here so the sixth thing that affects breathing is hyperventilation so if you're panting like a dog if you're breathing really quickly and you're gonna clear out all of that co2 so much longer or so much more co2 than normal is going to get cleared out so if I'm the medulla oblongata and I'm checking co2 levels well if you've purged a whole bunch of co2 it's gonna take a lot longer for the medulla to realize oh you don't have you know high levels of co2 it's like normally if I hyperventilate I would be measuring my co2 levels at a certain point but it's like in this case it's like if you hyperventilate you're dumping so much co2 that it's gonna take a lot longer for your brain to realize uh-oh there's a lot of co2 in here because you're like starting in the hole and so because of this hyperventilation can actually be very dangerous so hyperventilation can cause respiratory alkalosis where your blood pH actually goes up because you're getting rid of all of that co2 and therefore all of those H's but the danger of this is is if your blood your brain measures two things it measures carbon dioxide and oxygen so if your carbon dioxide is really low which would happen if you hyperventilate your brain thinks you have a lot of oxygen so that especially that respiratory system and your medulla oblongata that's just measuring co2 because why would there ever be a situation that you would have low co2 and low oxygen at the same time so your brain just assumes oh if co2 is low the haemoglobin must be carrying tons of oxygen when actually it's wrong so the result is it'll constrict the bless the blood vessels to the brain because if there's a lot of oxygen you kind of want to ship that oxygen to the organ very quickly so you can strip the blood vessels to speed up blood flow so you can see this is very dangerous because we've sped up blood flow yes but it is not high in oxygen we've tricked our brain into into thinking that and so dizziness which is fainting from low oxygen supply to the brain or from those vessels being constricted as a result of this and so this is very dangerous especially for swimmers because swimmers or divers will purposely hyperventilate so they can stay under the water longer well the problem is they're underwater when their brain tells them they need oxygen and they suck in water and drown so this picture here I drew I know I'm so artistic just kind of showing the alveoli and the capillary bed so the alveoli are those little round sacs and then the capillary beds remember tubes so this picture is showing it from the side like where you're looking into the blood vessel both of these vessels are lined with what we call simple squamous epithelium that we had an A&P one basically a single layer of those squash cells so we already did capillary exchange and we realized how thin capillaries have to be because otherwise things can't get in and out of capillary right well it's the same thing with the alveoli in our lungs that's why again we have all of that respiratory anatomy from your nose hairs to the goblet cells to the cilia to keep stuff out of the alveoli because if a dust particle gets down in there it's just gonna pop this thing like a balloon so this tissue is hella fragile so it can do the job it needs to do so an oxygen and carbon dioxide move back and forth from the alveoli to the capillary bed they have to get through two layers of cells and then this fused basement membrane that's between the two so we can't have it really be any thicker than that just like if you light a candle you can't put a bucket over it because then diffusion can't happen right so remember diffusion is moving from high to low concentration just like a candle sent moving through the air but nothing could move if these things weren't really thin but the price we pay is they're really really fragile so we call this the respiratory membrane two layers of cells with a fused membrane in between so this picture is showing a similar thing it's just I stole it from the internet so now it's showing the blood vessel more from the side so you can see how it's long and skinny just like we drew it in class when we did capillary exchange with cardio and so now we have this blood vessel here this little this little alveoli in this capillary kind of working together using diffusion so we've used diffusion countless times remember the goal is you're moving from where you're crowded to where you're not from high pressure to low pressure so we call this partial pressure it's just another way of saying how much of a gas is present so the gases are gonna move across this respiratory membrane which if you look at this picture is the two layers of cells with the membrane in between and we're gonna move from where we're crowded to where we're not so if you look at this picture that I created which one is gonna exert a greater partial pressure oxygen or carbon dioxide so don't overthink it obviously it's the oxygen because there's more oxygen right so therefore there's more pressure from the oxygen if you think of it like voting and we're trying to decide where to go to lunch and the blue circles are voting for pizza and the triangles are voting voting for tacos although both pizza and tacos are important the pizza is gonna have a stronger vote right so if we're talking about gases if we had a mixture of oxygen and carbon dioxide which we have in the air around us oxygen exerts a higher partial pressure because there's more of it so if we look at breathable air you do not have to memorize these percentages although I want you to know who's number one and who's number two so nitrogen is number one 78% of the air around you right now 21% oxygen so it's really important to have this mix because too much oxygen and too much nitrogen will actually do very weird things whereas carbon dioxide is only 0.04 percent of the air around us and 0.96 is everything else like sulfur dioxide and carbon monoxide coming out of your tailpipe so these numbers are crazy right so these partial pressures are going to determine the exchange in your lungs so it's very important to have this mix if you get too much nitrogen it will cause what's called nitrogen narcosis which is named after narcotics it'll actually make you high this is one of the dangers of scuba diving so when you go scuba diving if you stay down too long you'll get too much nitrogen dissolved in your blood and like I've taken scuba diving and I remember the dive master talking about how this one guy almost drowned because he took the regulator out of his mouth the mouthpiece out of his mouth and tried to feed it to fish he was that care fish suck on this and almost died he told another story about how they were down there and they were spearfishing for lobsters and one guy I shot his dive partner in the leg with a spear gun and when they surfaced the guy was so high because his tank was messed up that he thought his friend was a giant Lobster so it's like although funny that's kind of terrifying right see with oxygen if you go to the doctor and they put you on high levels of oxygen it can make you kind of euphoric and kind of high because we're used to just getting 21% oxygen but obviously if you're having lung issues you would need a higher percentage so this partial pressure stuff relates to another guy with very bad hair this is dalton's law of partial pressures and I'm not sure why this is so complicated the total pressure exerted by a mixture of gases is equal to the sum of the individual pressures like I don't understand what else it would be so it's proportional to the concentration of that gas meaning from my previous example oxygen had a higher partial pressure because there was more of it so what does partial pressure tell us this is telling us how much of a gas is present so the higher partial pressure of a gas the more gas is present in the air oxygen is 21% of the atmospheric gases carbon dioxide is point zero four percent of atmospheric gases therefore the partial pressure of oxygen is a lot higher than carbon dioxide in the air that we breathe because there's more of it so it's pretty common sense so how can we calculate individual gas pressure in the atmosphere so you don't have to do this math on the exam but basically we take the 760 which is our total atmospheric pressure and we take 21% of that to figure out the pressure of oxygen in our breathable air so we take point 2 1 times 760 and we get 160 millimeters of mercury in our breathable air if we compare this to carbon dioxide which is only point zero four percent which is point zero zero zero four times 760 we only get point three zero four millimeters of mercury in the air around this so the bottom line the higher the partial pressure and the air around us the more that's going to move into our blood so it's good that there's not much carbon dioxide in the air around us because we don't want carbon dioxide to come back in right so basically it goes gases move from the atmosphere from where they're crowded to where they're not they come into our lungs they go into those little sacs those little alveoli they exchange into our bloodstream at the capillary bed which we've drawn before and diffuse into the surrounding tissue cells how does pressure change so the partial pressure of oxygen diffuses in the blood the farther you get from the atmosphere partial pressure of carbon dioxide increases in the blood when you get really close to the tissue cells because they're the ones that are making it so no oxygen and carbon dioxide are both an arterial blood and venous blood just in very different amounts remember arterial blood is incredibly high in oxygen but it still has a little bit of carbon dioxide veins it's the opposite venous blood is incredibly high in carbon dioxide and just has a tiny amount of oxygen the exceptions being those pulmonary arteries and veins so how do gases move they move back and forth between the alveoli the blood and the tissues based on one thing diffusion remember these things go from where you're high to low concentration so if the partial pressure of oxygen in the alveoli is greater than the partial pressure of oxygen in the capillaries oxygen is going to move into the blood if the partial pressure of carbon dioxide in the lung capillaries is greater than in the alveoli we're going to move into the alveolar carbon dioxide is going to move into the alveoli to be exhaled so it's just all about diffusion things going from where they're crowded to where they're not so how is oxygen transported in our bloodstream 98% of it is attached to hemoglobin so we've talked about hemoglobin before and we did the blood chapter so remember one hemoglobin combined for oxygen but the bonds are very unstable so and we have oxyhemoglobin the oxygens not really tightly bound to the hemoglobin so I always think of this as if you're like holding pinkies with someone that's not a very tight handhold right if you have your fingers laced together that's pretty strong but if you're just lacing pinkies that's pretty unstable but this is good because we want this to break easily if I'm trying to drop the oxygen off we don't want them to be so tightly bonded to the hemoglobin that they won't let go we need it to go into the tissues and then diffuse into the cells but we wanted to lid we want to deliver it very very efficiently we don't have time for oxygen to just float around our body and hopefully get to our cells so it's good that 98% is attached to the hemoglobin only 2% is actually just flea free floating in the plasma so we want it to get where it needs to get as quickly as possible so you don't have to know the percentages but I want you to know that the majority of oxygen is being carried on the hemoglobin but there are a lot of factors that can affect how well oxygen and carbon dioxide for that matter bind to the hemoglobin so we call this affinity if you think of affection if you have affection for someone you like them right so hemoglobins affinity hemoglobins attraction for oxygen can vary so things that will affect how tightly oxygen binds to hemoglobin if your carbon dioxide levels increase well remember carbon dioxide and oxygen are both carried on hemoglobin temperature increases hemoglobin is a protein and proteins and temperature do not get along well so when things get hotter the proteins made to nature which means they may start to break down same thing with acids so the more acidic your blood gets the harder it is for the hemoglobin to carry oxygen because again hemoglobin is a protein and these things acids and proteins don't mix so if we think about protein structure it's the most complicated molecules in your body well we use our digestive system to break those down right well your stomach's very acidic we cook food right if you cook an egg it goes from that like snotty texture of an egg to that opaque white we can actually see the proteins breaking down so this is going to affect how how well hemoglobin can do its job so if your tissues are not getting the oxygen that they need we call this hypoxia so generically hypoxia is just you're not getting enough oxygen to the tissue we're not talking about why we're just saying it's not getting there and then the different types we have ischemic hypoxia so this is decreased blood flow to an area so we saw this when we talked about cardio because heart attacks are caused from ischemic hypoxia usually a blockage in one of the coronary arteries but it could also just be from sitting on your foot too long and it hurts right because those tissues aren't getting what they need histo toxic hypoxia histology is the study of tissues and so if the tissues are damaged they're not going to be able to use the oxygen so it doesn't matter if your bloodstream is dropping it off it doesn't matter if your lungs are picking it up if the tissues can't actually use it anemic hypoxia we saw this one we talked about blood this is you don't have enough hemoglobin for whatever reason remember there are so many different types of anemia but the end game is you don't have enough oxygen carriers so you'll become hypoxic and then my personal favorite hypoxic hypoxia because that sounds crazy this is decreased ability to carry oxygen due to low partial pressure of oxygen so this would be if you're in that library where they're restricting oxygen to protect the art or if you go up in the mountains or if you're on an airplane whenever you're on an airplane they always talk about in the event of an emergency if pressure drops they're going to drop those oxygen masks that's because if you were to step out of a plane at 30,000 feet the airs too thin there's not enough oxygen in the air that far away from the atmosphere so you can't bring you can't make the oxygen come inside your body because the oxygen is always going to go from where it's crowded to where it's not well if the air is really thin the oxygens not crowded so why would it go inside your body what would be the benefit of that so what happens when you have hypoxia we saw this in another chapter so remember your kidneys don't really care why they're not getting oxygen but if the kidneys aren't getting oxygen they will release a wreath ro poitain and that was that hormone that tells your bone marrow to get busy and so you'll make more red blood cells so remember athletes cheat by injecting this or if you go on vacation in the mountains the first couple of days are really hard and then after about four days you're making enough blood cells to compensate then you come back down to sea level and Danville and feel like a freakin rock star because you have so much oxygen carbon dioxide is transported in with the hemoglobin as well but not the majority of it so again you don't have to know these percentages but I would want unit to know that the majority of carbon dioxide is in that form of the bicarbonate in your blood plasma so after the carbon dioxide bonded with the water it splits into the hydrogen ions and this bicarbonate excuse me so most of it is being transported in that form 23 percent so definitely not the majority but still a decent number is attached to the haemoglobin so now we call this carb Amina hemoglobin which is super fun to say carbon dioxide is not carried on the hemoglobin on the same site thank goodness so there's no competition directly between carbon dioxide and hemoglobin so I think of this like if you're carrying your kid and your purse you would carry your kid on one hip and your purse on another or if you're carrying like a kid and your groceries you have a kid on one side groceries on another they're not competing for the same part of your body meaning it does if you had tons of carbon dioxide in the hemoglobin this isn't going to affect how much oxygen you can carry and then about 7% is just floating around in the blood plasma in the form of just regular carbon dioxide so the point is the majority of oxygen 98% is carried on hemoglobin whereas only about 1/4 is carried on the hemoglobin when we talk about carbon dioxide then we have this scary guy carbon monoxide so carbon monoxide is the stuff that comes out of your tailpipe so some people kill themselves please don't do that by parking in a closed garage and turning their car on and you'll basically just go to sleep carbon monoxide poisoning is so dangerous because carbon monoxide is carried on the hemoglobin where the oxygen is carried so it's competing for the same spot so remember oxygen binds to the hemoglobin really weakly we want that because we want to just be able to drop the oxygen off right and get it where it needs to get well carbon diet or carbon monoxide is gonna bond to the hemoglobin 200 times stronger than oxygen so it's not gonna drop off anywhere so it eventually gets to every time you take a breath there's nowhere on the hemoglobin for the new oxygen to go because there's a big fat carbon monoxide sitting there so this is why you get very tired because you need oxygen to make ATP and without oxygen your body just slows down until it completely stops but a lot of times carbon monoxide poisoning is accidental like if people have leaky furnaces or one of the weird things with hybrid cars which I have people forget to shut them off which I know sounds crazy but they're really quiet so they're actually I believe it's about 20 people a year or dying in the United States because they parked their car in their garage forget to shut it off and then oftentimes their bedrooms are like above the garage and the carbon monoxide poisoning kills them so why do we breathe oh it's all about our super-fun friend cellular respiration so we're not doing the steps again okay but if you remember cellular respiration we had glycolysis kreb cycle or citric acid cycle and the electron transport chain or system the gist was we had an anaerobic phase and an aerobic phase so if you remember you can break glucose into pyruvic acid c6 into c3 without oxygen so that's the first phase the second two phases you have to have oxygen so all we really care about from this slide is the important of oxygen so carbon dioxide is a huge waste product from cellular respiration that's why we breathe right we've got to get the co2 out of there the oxygen that we're breathing in is going to be the final hydrogen acceptor at the end of the electron transport chain so without oxygen we're screwed without oxygen we can only make two ATP verses 32 to 34 ATP so the whole point of this slide is the respiratory system is all about getting rid of that co2 and bringing in that oxygen so that way we can keep this cycle going without oxygen all we can do is step one and so two ATP verses roughly 34 if you're car goes from getting 34 miles per gallon to 2 miles per gallon you're in some trouble and so your body is the same way so we've got to have oxygen to make ATP