the other part of this chapter is the lymphatic system which is also known as your immune system we always start every chapter with what's kind of the point in purposes so the points and purposes of the lymphatic system that are important first of all transporting excess tissue fluid away from the tissues and back to the bloodstream lymphatic vessels ultimately dumped into the blood so whatever's in the lymphatic system is going to end up in your cardio as well so this is a really important thing if we go back to that capillary exchange how we always send out more in the beginning then we pick up at the end it's better to overfeed than to not feed enough so we always filter way more water in the beginning of the capillary bed because of blood pressure then we do reabsorb at the end but that's okay because this is our backup so this guy is in there to basically squeegee up that excess fluid that cardio doesn't simply have the time to deal with lymphatic is of course to defend your body against disease we do this by filtering the body fluids looking for bacteria and viruses but also just bits of dead cells and then we've kind of previously mentioned this about lipids lipids are essential to your diet you have to have fat you have to have it in your bloodstream but remember at the intestinal level if you're absorbing fat lipids are huge they're huge molecules and so that capillary exchange isn't going to be able to suck them up well lipids can be sucked up by the lymphatic system so that's why I say it's kind of like a middleman so diffusion of lipids just directly into your bloodstream is very limited just because of size and time whereas if I put it in the lymphatic system lymph is gonna dump it to the blood anyway lymphatic pathways these are very similar to cardio as far as the pathways that they take in fact lymphatic vessels if you remember that previous picture from another PowerPoint lymphatic vessels look a lot like blood vessels but instead of carrying blood they're carrying lymph that's why they're called that which is water would dissolve stuff remember I said it kind of looks like milk that's got some you know really watered-down milk from the capillary beds to your thoracic duct so your thoracic duct is this dumping point near your left clavicle you do not have to know that we're not doing that in lab lymphatic tissue however we will see quite a bit of this in lab lymph tissue is basically loose areolar connective tissue so it's lots of collagen for strength remember those are like ropes that you pull on really strong elastin like bungee cords have a nice bounce and then lymphocytes remember the angels of our immune system so this is tissue that's positioned all over your body to help you fight the good fight so some examples your appendix tonsils spleen and lymph nodes when you get the second two anatomy last or list for the second practical all of these will be on there now I know you guys tend to judge me when I draw on PowerPoint but I was pretty proud of this one I thought it this picture turned out pretty good so this is showing that capillary bed remember capillaries have those fenestrations which are just the little pores for things to leave whereas lymphatic vessels have a dead end remember your blood goes round and round you have a closed circulatory system so your blood is somewhere in a blood vessel well lymphatic vessels have these kind of dead ends these one-way vessels and so they're kind of like creepy little fingers that get in there and kind of squeegee up the excess fluid so if your blood let's go if too much interstitial fluid which is proper too much fluid the interstitial fluid the fluid surrounding the cells will become too full but again it's better to send out through filtration more water that has good stuff in it and worry about kind of sucking it up later because these guys are the backup so these guys will squeegee up that excess fluid dumps into the bloodstream anyway this is just showing you the pathway from Limp from the tissues back to the blood we're not doing this in lab so you don't have to know thoracic duct or cisterna Chile but it's just kind of showing the pathway that we have these lymph capillaries which are running right next to your regular capillaries that merge into larger lymph vessels and they can either go two ways the thoracic duct to the subclavian vein or the right lymphatic duct to the subclavian vein so either way we're dumping into the blood stream into those subclavian veins which go back to the superior vena cava and then to the heart again we're not really caring about this Anatomy it's just kind of showing if this picture is black and white I don't know if I would immediately recognize those green things as being lymphatic vessels I might assume they were part of cardio so the left drainage area is a lot bigger than the right remember the left side is that you know force at the left side of the heart being so much thicker and be steer and so it's not an equal drainage but again we don't really care about thoracic duct versus cistern or chill I I just liked this picture as an example of how closely those lymphatic ducts run next to your veins so the paths have fluid in the body we have the heart we have the major arteries we have the arterioles we have the capillary bed we have the venules and we have the veins so that's basically what's going round and round in this picture so remember arterial blood has the highest pressure in your body venous blood has the lowest pressure so this is showing that lymphatic vessel is kind of a one-way street and I really like this picture because if you look at the end of that lymphatic capillary how it looks like creepy little hands so those creepy little hands are there to squeegee up any of that excess fluid that the arteries pumped out because it was a again better to send out a lot more good stuff at the beginning of the capillary bed and worry about picking up the excess later there are a lot of similarities and differences between blood and lymphatic fluid so this is a huge difference between lymphatic fluid and blood three liters per day versus five liters per minute remember your blood is going round and round your body about every minute whereas lymphatic you're doing maybe three liters a day so the point is it's very very slow otherwise though if I look at this picture on the left it really does look a lot like cardio or even nerves I like this picture on the bottom right that's showing those creepy yellow lymphatic capillaries kind of going in there and reaching up and grabbing that excess fluid so lymphatic fluid is really really small like the amount you're pumping every day three liters per day and the lymphatic fluid has these dead ends in the beds the lymphatic vessels themselves as I've said about four times now generally more fluid is going to leave the capillaries than your reabsorbing it's better to throw out more good stuff like sugar and hormones and oxygen than worry about picking up the waste necessarily I mean if you had to choose one so blind pathways are a huge difference between lymph capillaries and blood but otherwise thin walls they're more permeable than blood vessel walls but remember veins have really really thin walls so do capillaries so I mean the fact that lymphatic capillaries are thin is kind of similar to some of the blood vessels so proteins and fats can can pass through these lymph capillaries so that's the benefit is they will accept kind of larger molecules lymph vessels also have those one-way valves that we saw on a previous diagram remember veins have valves as well so they have some similarities to both the cardio and lymphatic how do these fluids move well we just spent you know an entire chapter on of course the heart so blood is being pumped by the heart that's why the arterial side moves so much faster than the vena side remember the veins kind of suffer because they're so far from the heart but lymph doesn't tap the heart lymph doesn't have a pump at all so he's gonna move kind of similar to vein the vena system but this guy doesn't have the heart helping at all so contraction near my muscles you gotta move right the longer you sit the more your ankles swell I was on a flight once for 14 hours when I got off the airplane I was like where did my ankles go I've been in cars where I've driven as long as like 25 hours straight and again I look down and I'm like weird and my ankles go so you got to move around you got to pump those skeletal muscles especially at the lower extremities just like we do from the vainest system or we get edema thoracic presser pressure when you take a deep breath similar to veins pushing on the inferior vena cava when you're breathing breathing helps push on the lymphatic vessels as well and then one thing that's completely different than veins the fact that we form new lymph so the new lymph pushes the old lymph out whereas new blood doesn't push the old blood out because the blood goes round and round and round but because the lymphatic vessels have these dead ends when you make new it forces the old into the superior vena cava via the subclavian veins on both sides so there are one-way valves and pressure differences are what forced it to keep moving in one direction lymph nodes you've probably heard of lymph nodes a lot of times when you go to the doctor they'll poke around and try to find lymph nodes I don't know if cuz they're covered in fat that's probably the answer but hmm I've never felt my lymph nodes so people say they feel like like really like bee bees or like really hard garden peas or something so like just really small circles that they get quite painful so these guys are common where your lymphatic vessels merge so your armpit your groin mammary glands are where tons of these are because these huge blood vessels are coming together if you look at that picture in the bottom corner the lymph nodes are those little swellings that are on those lymphatic vessels the point is you have 600 to 700 total so if you ever have to have a lymph node removed it's not usually that big of a deal to have it removed you can be without it because you have so many backups so these guys contain lymphocytes remember the lymphocytes are the angels of our immune system they're gonna attack viruses and bacteria and give us antibodies there's also a lot of macrophages in there which are just those general garbage collectors cruising around doing phagocytosis gobbling up damaged cells and cellular debris so lymph nodes are good things to have around right they're like defense so it's kind of like we have army bases all over the world well we have lymphatic vessels all over our bodies and lymphatic lymph nodes all over our bodies to help defend us but if a base were to close our military could survive well if we got rid of some of these lymph nodes our immune system can survive but it's best to have our protection spread out we wouldn't want to just protect ourselves from viruses like in our hands we obviously want that viral protection everywhere one of the glands we mentioned when we did the endocrine system was the thymus gland this guy has more of an immune system role which is why we didn't do too much with him with the endocrine system so this is right behind your sternum remember this guy is real weird because he gets bigger as you get hurt sorry he gets smaller as you get bigger which hardly ever happens right most of your parts get bigger as you age so this guy makes thymosin hormone and that changes your lymphocytes some of your angels of your immune system into what we call T lymphocytes so they're actually named for the thymus gland your spleen their spleen is actually your largest lymphatic organ we saw him when we talked about blood because he's making blood when you're a fetus but he has a lot of other jobs as an adult that are very protective so that's why he has a lot of lymphatic roles so this guy's filled with blood there's lots of macrophages in there gobble gobble there's lots of lymphocytes to filter foreign matter and damaged red blood cells remember the spleen is the red cell red blood cell graveyard but we have a wreath row poised to sin our spleen before birth because we don't have bone marrow yet and as an adult as we saw before when we're talking about blood this gives us a nice reservoir of blood if you donate it donate blood or have a tremendous blood loss the spleen can spasm and release that and kind of give you an extra shot of blood but along with the liver his main job is to destroy red blood cells as they age because remember those guys only last about 120 days tonsils some of you maybe without some of your tonsils but tonsils are basically just lymph nodes and so their goal is to filter swallowed and inhaled material so if we think about where they're located which you'll see the picture next because this will be again on our second Anatomy list tonsils are located where you're very vulnerable the respiratory system is very vulnerable because you obviously have to breathe right which means who knows what is in that air that you're consuming so we have the Palatine tonsils these are what you think of as tonsils when your doctor tells you to open up and say ah these are the Palatine so these are in the back of your throat on either side and when they get infected we call this tonsillitis it's a very common sight for infection because a lot of people have tonsils that are like little raisins and so you have a lot of folds that the bacteria can kind of grow an especially strep if you've ever had strep throat chances are you've had at multiple times my husband finally had to get his tonsils removed because he had strep five times in one year I've never had strep my doctor actually says my tonsils are like freakishly smooth so there's just not a place it's not a lot of places for the bacteria to get in there and party it up pharyngeal or adenoids and either one of these terms is acceptable for lab these guys are up in the nose so a lot of people hear about adenoids being removed when people are having snoring issues or breathing issues and often time when they when they go in to remove the tonsils like they did for my husband they'll sometimes take the adenoids at the same time and then the lingual tonsils which no one ever thinks of or has usually even heard of these are at the back ear tongue if we look at a picture of this and we have these models in lab either that head on a speak or there's a head that's on a wooden plaque that we haven't really used yet you'll see these three sets of tonsils so if you look at the top there the fair and pharyngeal or adenoids those are perfectly located to kind of filter out your nasal air right so if I breathe something into my nose that's potentially pathogenic potentially disease-causing hopefully this guy will filter it out with his macrophages and lymphocytes further on down the pharynx which your pharynx is just a generic word for throat because the throat is the common pathway for food air and drink and so we call it a throat we call it the pharynx then it splits into the esophagus which goes to your stomach and the trachea which goes to your lungs and so this is all anatomy that we'll be dealing with in lab very soon so the Palatine tonsil that's the one again that we think of when we're thinking of tonsils that's the one in the back your throat and then notice that little lingual tonsil it's right under your tongue so linguistics is the study of language it's which of course you use your tongue to talk that's how I remember the word lingual tonsil the appendix something else my husband is without 7% of people will get their appendix removed I still have mine at this point our cadavers have them as well but this is a lymphatic tissue and so if you look at the bottom picture the before and after the appendix is not a very big structure the function is very unclear so we actually call this structure vestigial which is a word that means it probably had a function at some point and it doesn't anymore and so a lot of things in our body are becoming vestigial like body hair most of the body here we have we spend our lives trying to get rid of right so especially like the hair that's on your arm that hair doesn't really keep you warm anymore so it doesn't really have a purpose or your canine teeth if you think of your canine teeth your vampire teeth in comparison to like your dog or your cat our teeth aren't very sharp anymore but canines are for ripping and tearing into our food and when's the last time you rip and tear it into a chicken nugget I mean I like them but I don't like get all ambitious and rip and tear into them we more just need to kind of grind our food so our canines are kind of slowly flattening over time so there are lots and lots of examples of bestial structures in our body and so what they think what evolutionary biologists think the appendix used to be for was they think it used to be like an extra pocket of bacteria to help us when we were digesting our food because especially before we start cooking our food we probably exposed ourselves to a lot of bacteria a lot of viruses a lot of parasites and so this was kind of a way to like give us some like immunity protection well we don't really need that anymore because we have antibiotics we cook our food we're not eating a lot of things raw anymore I mean when's the last time you got hungry and you chase down a deer and just bit into the ass end of it it's like we don't do that anymore right so we kind of need don't need that built-in protection and so it's getting smaller eventually it'll probably just completely go away but we'll be seeing them on the cadavers the good thing about the appendix is it gives us the opening to the cecum which is the large intestine because otherwise even though the named small large intestine makes it seem like it would be really easy to tell it's actually really hard to tell on cadaver but just like anything else that's good for us like tonsils are there to protect us but we can get tonsillitis this guy can also get in fact and give us appendicitis and you can even die one of the biggest roles of the lymphatic system is to pick up that excess fluid from cardio so causes of edema immobility is the big one the fact that when you're a mobile not as much water is going to return to the bloodstream and gravity is a right so gravity's going to kind of pull a lot of that water downward especially from the veins heat you ever noticed that on a hot annoy day sometimes your clothes feel really tight or like I'll start the day if my hands are cold I can spin my wedding ring around but like if I get really hot I can barely move it your tissues tend to swell when it's hot because those capillary beds they those fenestrations those pores dilate and they'll let more fluid out salt intake if you eat a lot of salt a lot of people will notice this that their fingers will swell if you eat a lot of salt your body will try to dilute it by kind of holding on to more water heart failure because your pumps not functioning so especially on the vein side that's going to take an abuse and kidney disease can cause edema because kidneys have so much to do with water balance