all right ninja nerds in this video we're going to talk about the development of the vascular system before we get started hit that like button comment down in the comment section and please subscribe also down in the description box with a link to our facebook instagram patreon account go check that out all right let's get into it all right ninja so we're talking about the development of the vascular system we have to accomplish three particular goals the first thing we have to do is talk about how do we actually develop blood vessels arteries and veins we'll get to a little bit later but how do we actually make blood vessels from our trilaminar disc within the embryo and then the next thing is how do we actually take and after we've made those blood vessels and sprout more blood vessels off of it that's kind of the first goal so let's target that first vasculogenesis and angiogenesis is our first goal so the first thing we're going to do is orient ourselves here okay what the heck is this thing here this is the tri-laminar disc right so if you're taking a cross-section through the embryo you're going to get something looking like this around the third kind of weak all right the top layer here this blue layer here is called your ectoderm right this layer here in the middle is called your mesoderm and that's the one that we're going to pretty much focus on throughout this lecture and then this most bottom one or in this case if we really want to be anatomically specific the ventral part all right because when you're looking at the embryo this is the ventral part this is the dorsal part of the embryo this is the endoderm and if you really wanted to expand on this above the ectoderm is the amniotic cavity and below the endoderm is the yolk sac and then what you have here is you have this neural tube right this kind of like maroon colored structure kind of sandwiched between the mesoderm this is called your neural tube and then last but not least we're not going to write it down but this little black structure here below it is called the notochord all right what i really want us to focus on is this mesoderm because that's the layer that we have to talk about so what i'm going to do is i'm going to denote this okay 1 2 and then this last area here which is going to be 3 and then we'll annotate these parts here in a second all right so we have two different parts of three different parts of the mesoderm if you will the first part of the mesoderm which is the part just on the sides of the neural tube and the notochord is called the par axial mesoderm okay this is the part that becomes the somites right we've already talked a lot about that in the skeletal system and the muscular system all that good stuff the one just lateral to the par axial mesoderm is called the intermediate mesoderm okay this will become kind of your gonads in your urinary system and we've talked about this with the actual urinary system and then the last one here is the lateral plate mesoderm now what happens is when you look at the lateral plate mesoderm you develop a little celium here called the intraembryonic sealam it's this little space here between these two parts of the lateral plate mesoderm all right so now if we take and look at the parts of the mesoderm these two kind of like strands right that are part of that lateral plate mesoderm there's a space that develops between it we already talked about it's called the intra-embryonic cellum the part of the ladder plate mesoderm that moves with this blue layer the ectoderm and moves around the yolks the actual amniotic cavity that one which we're going to put in blue here is going to be called the the somatic layer of the lateral plate mesoderm so it's the somatic layer the other one which we're going to color code is green which is this bottom one which will move with the actual endoderm and then around the yolk sac that is going to be called the splanchnic layer so the splanchnic layer of the ladder plate mesoderm this is the layer that we are going to be focusing on it's involved with the development of the cardiovascular system we've already talked about the heart in one video now what we're going to do is we're going to talk about the vascular system now the first thing that happens is that this endodermal tissue starts releasing large amounts of particular types of growth factors that are going to directly influence this splenic layer of the lateral pleumesider what are these growth factors that are being released by that actual endoderm what are these chemicals here that are influencing the uh the splunk nuclear lottery mesoderm these chemicals here are called vascular endothelial growth factor and this is really important vascular endothelial growth factor or vegf is going to tell that splanchnic layer the mesoderm layer to start proliferating and then differentiating into particular types of tissues what is it well let's take a piece of that mesoderm just take that piece of that mesoderm here and we're going to kind of zoom in on it if you look at that piece of mesoderm okay we're going to call this all just the mesoderm mesoderm is pretty much mesenchymal cells okay mesenchymal cells what happens is with the vegf okay with what type of chemical here the vascular endothelial growth factor it causes some of these mesodermal cells to proliferate but then also differentiate and then what starts happening is let's imagine here you have another part of that mesoderm around this some of the areas start kind of specializing and forming a tube okay so now i'm going to have within this mesoderm little tubes okay these little tubes are actually going to be made by particular cells that are lining that tube this part the cells that are lining these tubes these little cavities here are called your angioblasts okay and these are going to give rise to what's called your endothelial cells you know endothelial cells they basically line our blood vessels they form what's called the endothelium or they line the heart cavity and make the endocardium that is one important thing so the mesoderm differentiates into angioblasts which make endothelial cells for heart tubes and blood vessels but also some of the mesoderm differentiate and form particular types of cells in these tubes that move through the tubes what is that called these are called hemo cytoblasts okay and hemocytoblasts will become your your red blood cells they'll become some of your white blood cells they'll become your platelets what are these called they're formed elements right that's what's moving through the tubes which is moving through your blood vessels and your heart pretty it makes sense right then what happens is the next thing all these tubes are connected all these tubes are kind of like separated if you will what we're going to do now is we're going to have all of these tubes connect kind of like canalized between one another so now when they do that let's canalize all of these tubes and i'm going to kind of form a little canal throughout all these tubes so all of these are going to start connecting with one another and make one long tube and then what's going to kind of be moving throughout that tube all your formed elements doesn't that look like a blood vessel that is a blood vessel this process right so where we actually what is this called where we can alize so we're going under what's called canalization and we make this actual blood vessel this process up to here is called a vasculogenesis what is it called vasculogenesis so what have we covered up to this point vascular genesis beautiful now that begs the question what in the heck is angiogenesis i'm glad you asked guys so angiogenesis is now what i'm going to do is i'm going to take my blood vessel i've made a blood vessel i've made a heart tube and then i'm going to start sprouting off of that more blood vessels do you see the difference here i started with mesoderm and made blood vessels but when i take blood vessels and make more blood vessels that's angiogenesis when i take mesoderm and make a blood vessel that's called vasculogenesis so make sure you understand the difference here so now we're going to do is we're going to draw our heart tube and then what do these like if i form like little vessels that come off of it what is this process here called this process is called angiogenesis so again what is this process here called it's called angiogenesis beautiful okay that's this process now what we understand is how we actually take from the baby's mesoderm the splenic layer and make blood vessels and then sprout blood vessels off of it let's take a look at what that would actually look like okay in kind of a process this kind of uh moving on throughout the story if you will so let's say that that actual endoderm layer has released a lot of that vegf and so now you start seeing that that lateral play mesoderm is proliferated here a little bit but then some of that ladder plate music started doing what making differentiating and forming heart tubes or blood vessels if you will so it's going to form a little blood vessel in cross section so we're not going to see the entire length of the tube in this type of cross section we would in a sagittal section but here is going to be your heart tubes which will help to make parts of your blood vessels we'll take a look at what the heck that heart tube looks like in a second the other thing is you also form another little tube back here called the dorsal aorta we're going to put that one like right here you're going to form the dorsal aorta so we formed two tubes two tubes this tube here in the front is going to be what's called your heart tube okay it's called your heart tube and the whenever the undergo the folding process these two heart tubes fuse we talked about in the development of the heart these tubes here in the back behind the heart tube is called your dorsal aorta okay you got two of them and then what happens is during the process of folding they fuse okay so now we have to do is we've taken through this process of vascular genesis and angiogenesis started making blood vessels now what i gotta do is i gotta i got two heart tubes and two two a horde i gotta make one heart tube and i gotta make one aorta so i wanna start undergoing this process of folding so we're gonna undergo what's a process called lateral folding and again this would be the same thing in the craniocaudal folding but it's i think it's better to see this in that lateral folding process so when we go through the lateral folding process now look the ladder plate mesoderm has gone right we have those two heart tubes as they fold and these two edges come together endoderm comes together ectoderm comes together and make a nice little cylindrical shape here and then that heart tube right here is now one do you have two heart tubes fused together and make one heart tube so this is a one heart tube and then if you look back here we had the two dorsal aorta right they're going to actually fuse but there's these little things that we'll talk about in a second how they actually they come and if you look up higher like when you're in the actual chest cavity they're coming off of the heart tube we'll see it easier in a second they come off the har tube and move backwards into two dorsal jordae but as the dorsal already moved down down down the actual spine or down the actual embryo they fuse together a little bit lower in the embryo and make one aorta so i know it seems crazy because i said oh we have to fuse these dorsal aorta they do but you just don't see it at this view because we're upper higher in the embryo so again you're still going to have the dorsal aorta but again realize that they are fused as you go lower down the embryo you'll see it here in a second okay beautiful now what i want us to do is we've formed our heart tubes and part of the heart tube will make our blood give us way to blood vessels and we form the dorsal aorta we haven't seen the venous system yet we'll talk about that later because that's going to come off of that hard tube but what i want us to do is really kind of dig into developing arteries and developing veins now that we understand how we made blood vessels so let's move on to the next step which is actually going through the development of the arterial system all right so we formed that heart tube and the dorsal aorta i wanted to give you guys a look at what it actually kind of looks like so let's imagine we took that heart tube and we pulled it out of the cross section so you can see the entire length of the heart tube right this is what you're going to kind of get now we have to denote the different parts of the heart tube and if you guys if you already watched our development of the heart video this should be very easy what's the bottom part sinus vinosus above it primitive atria above that primitive ventricle above that is the bulbous cordis above that truncus arteriosis and then above this the one we really got to focus on the aortic sac and then the aortic sac move out we said they'll move backwards into the dorsal aortae so this is going to be i'm going to abbreviate that dorsal aorta dorsal aorta now we're going to focus on this system first okay talking about how we develop the arterial system which is pretty much going to be focusing on this area here later in the lecture we're going to talk about this system below here the sinus venosus and these inflow tracts which are going to be via those cardinal veins the umbilical veins and the vitelline veins but for right now let's just focus on this upper part here so if we would actually take another cross section but take the cross section through that embryo at this level the level of the aortic sac and look at this in a cross section within the embryo you're going to get this view so this is our cross section of the embryo at this level where the aortic sac is so underneath this would be the truncus arteriosus but what let's give you guys some anatomy here this portion here is called your aortic sac what are these things coming backwards we said goes backwards from the aortic sac backwards into these little structures this is your dorsal aorta this is your dorsal aorta okay we understand that right the blue is the ectoderm and the green is the endoderm that's going to give way to your gut tube right foregut mid-gut hindgut and what's the highest part of that gut tube where the primitive pharynx is right the pharyngeal apparatus and then back here is your neural tube here's your notochord here's what i want that's very interesting it's pretty cool you know when you take a look at the actual pharyngeal arch system right if you kind of like if you imagined here if we were to kind of cut through at the upper part at the pharyngeal arches you have these things called the pharyngeal pouches right and that's these inner parts here and then around the pharyngeal pouches you have some mesoderm right kind of a core of mesoderm so these are called differential pouches the green part around that is the pharyngeal arches and then outside of that is up some ectoderm in the ectoderm form what's called the the the clefs are the grooves okay what i want you to remember is this here this endoderm i want you to think about it right here this is the inner part of the endoderm which is like the pharyngeal pouch system on the sides here this red color is what your pharyngeal arches so what i want you to think about these as these here are going to be the pharyngeal arches but what part it's that mesoderm core of the pharyngeal arches right so here's the pharyngeal arches which is that mesoderm core here's what's really cool we formed the aortic sac right by the process of vascular genesis what did we call it whenever you took a blood vessel and made more blood vessels angiogenesis watch this from the aortic sac it makes blood vessels that move to the pharyngeal arches and then through the pharyngeal arches which is mesoderm they're going to make some blood vessels and that is going to have a little bridging connection between what the aortic sac to the pharyngeal arches to the dorsal artist so throughout this entire process aortic sac to dorsal aorta you have to go through the pharyngeal arches which is going to form blood vessels in this area too this connection here as you go from the aortic sac all the way to the dorsal aorta through the pharyngeal arches this whole black structure here is called a aortic arch and you form a bunch of these at all the different levels we're only seeing this at one cross-sectional level so again if i start from the aortic sac form blood vessels that run through the pharyngeal arches the mesoderm core and then move their way into the dorsal aorta what is that called an aortic arch you form a bunch of aortic arches that are running from the aortic sac through the pharyngeal arches and then to the dorsal aorta you know how many of them let's take a look if we zoom in here and we actually look at what this would look like pulling just that structure out nothing else around it here in the center is your aortic sac on the sides is your dorsal aorta right here is your dorsal aorta from the aortic sac via the process of angiogenesis you run blood vessels through what structure the pharyngeal arches they help to make some blood vessels and then bridge that connection to the what is this called dorsal aorta what is these connections called this is called jeroric arches look how many you have you have the first arch first aortic arch second aortic arch third aortic arch fourth aortic arch and here's where it's a little odd sixth aortic arch you're probably like what the heck what happened to this the fifth one fifth ones ins and textbooks they say it either doesn't form or if it does warm it digresses pretty quickly so you really don't even consider it so from the aortic sac to the dorsal aorta we made how many total arches technically five aortic arches but we're missing that fifth one so it goes one two three four six now remember i told you that we said that the aortic sac connects to the dorsal aorta right from that view over there then what do we say as the heart is actually undergoing that folding process what happens the dorsal aorta come together and fuse and then this part of that aorta will then move downwards right and go and supply like the lower parts of the baby within the embryo and this is the part that we'll talk about over here okay what we need to know though is what the heck do these aortic arches become in the actual adult or as you start to grow within the embryo so take a look over here all right so we talked about the formation of these aortic arches right and then we talked about how the dorsal layer will fuse together and they start flowing down right we if you just really want to remember this is going to go down to that like descending aorta and this is the part that we'll talk about a little bit later which is what all those structures the descending order go and make but if we come back to the arches eventually this is what it looks like during the development of the vascular system but as you get towards the end goal which is what it should look like as an adult this is kind of the structure that you get okay and it's important to know what these arches become because it's going to become this structure here so what i want us to do is write down okay all the different derivations of these arches okay so here's what i want you to remember first arch remember that the first is the maximal it's the max that you can become so the first arch will become the maxillary maxillary artery that's the big one okay so the maxillary artery that's going to be the derivation of the first arch the second arch is a weird one but it will become the hyoidal artery and then the hyoidal artery will give way to what's called the stapedial artery usually this stapedial artery it's very rare for it to actually exist in humans very rare maybe 10 percent of people so this one is not something that you're commonly going to be you know seeing very often but here's how i remember it first arch first is the max so maxillary artery second s stapedial artery that would be the main derivation of the second arch but a brimmer it's pretty rare that it actually consists and progresses the third arch what's the third letter in the alphabet c so you want to remember that this is the common this gives way to your common carotids your common carotid arteries and the proximal part of the internal carotid arteries so your ica so again i like to just remember you're going to have carotids in there somewhere common carotids or internal carotid artery third arch third letter in the alphabet is c fourth arch okay you have two of these fourth arches right so we talked about pretty much the consistency here this is where we have to be a little bit more specific about the right and the left arches with the fourth arch you have the right fourth arch and then you have the left fourth arch the right fourth arch is actually going to give way to the right subclavian okay so it'll give way to the right subclavian artery and even parts of what's called the brachiocephalic artery we'll kind of recap this in a second the left will become the aortic arch from the point after the brachiocephalic artery down to the left subclavian okay and again we'll talk about that in a second the last one here which is the interesting one which are going to come down here right off oh but real quick so we have that kind of mnemonic first first is max maxillary artery second s and second is stapedial third third letter in the alphabet is c carotid it's fourth arch you have four limbs you know the right subclavian will supply the right arm the aortic arch we said where does this actually start after the brachiocephalic and it consists of the left common carotid and the left subclavian where's the left subclavian go to the left arm the aortic arch continues downwards into what the descending aorta the descending order moves down the abdomen gives way to your common iliacs common iliacs eventually go into external iliac and then down to the lower limbs so you see how forming these two big structures gives way to your four limbs so fourth arch remember the four limbs all right so the last arch here is the sixth arch now the sixth arch okay i didn't have a great mnemonic for this one but it'll do so the right one is going to give way to the it's pretty straightforward the right pulmonary artery so the right pulmonary artery the left arch is going to give way to the left pulmonary artery and one more thing what's called the ductus arteriosus so you're probably like okay well zack you got a mnemonic for the sixth one not really i just i don't know the sixth arch think about them sexy pulmonary arteries i don't know whatever you want but for the most part this is going to be the derivations of all of these arches now let's kind of have an idea of how all of this would look then so if you look here we're going to have here what is this structure going this way this is your pulmonary trunk right we got that from the trunk of sarteriosis but then it splits into the pulmonary arteries here right so here you're going to have your what right pulmonary artery over here you'll have your left pulmonary artery and then what's this connection going to be here between the pulmonary trunk and the aorta this is called your ductus arteriosus in the embryo we'll talk about that more in the actual fetal circulation again you're going to have the ascending order that's developed from the truncus arteriosus but then coming off of this you have the aortic arch okay and what do we say the aortic arch was developed from the fourth arch particularly the left one it's going to actually give way to what structures here well if you remember it starts kind of right after the brachiocephalic and then continues this way one of the branches is going to be the left subclavian artery then again the aortic arch will continue down via the descending aorta and that'll actually help us to take down into the abdomen and then to the lower limbs then we have these structures here these are your common carotid arteries okay this would be the right one this would be the left one and then here you're going to have the right subclavian artery so you have an idea of what the arterial system should look like coming off of the heart and how it's actually derived from those aortic arch systems now what i want to do is we're not done with the arterial system we got to continue down into the descending aorta and look at some of the branches that come off of that let's do that now all right so we talked about that aortic or arterial system that's coming off of that heart tube right and then we have to talk about the continuation so remember we said that as the kind of you formed kind of the aortic system the arterial system right you form the pulmonary arterial system and then the systemic circulation from the aortic arch we're going to follow that aorta downwards into the descending aorta as it goes through the abdomen and then through the lower limbs so here is going to be our descending aorta here's what i want you to remember the descending order is going to go down the length of the embryo okay as it does that along the length of it it gives off three particular types of general branches okay that i'm going to be representing here in blue actually we're going to be more specific four types of these branches okay the ones that come off the back these are called your dorsal lateral branches pretty straightforward right so these are your dorsal lateral branches here coming off the actual sides these ones are pretty straightforward these are your lateral branches okay we're going to abbreviate these lateral branches dorsal lateral branches these are the ones that i really want you to remember though this one here that's coming kind off the center of the embryo off the aorta if you imagine a baby let's imagine here we're in the abdomen you know there's a a tube called the the vitelline kind of duct and it connects the embryo to a little thing here called the yolk sac this artery actually runs into the yolk sac okay and so this is called the vitellin artery since it runs through that kind of like vital runs with the vital and duct so this right here is called your vitalin artery now that's not what we have in the embryo we have something else so we're going to talk about what the vital artery becomes the other one is this guy here you see these two little guys here that are coming right off the at the beginning point of where the dorsal aorta branches these little arteries here that are coming off the side are called your umbilical arteries okay these are called your umbilic arteries you have a right and left umbilical artery this is what it would look like okay as you start the beginning of kind of like the fetal circulation what would it look like as you progress towards kind of the goal which is an adult kind of circulation here so that's kind of the question what do those do posterior or dorsolateral branches become what are the lateral branches give away to and what does the vitalin and umbilical artery become right that's the big question all right so let's focus on the dorsal lateral arteries think about it simply if it's going dorsal and laterally what kind of runs back here the ribs right so you have intercostal arteries and then if you go lower you have lumbar arteries so on the back here these dorsolateral branches will give way to what structures here this will give way to the intercostal arteries and the lumbar arteries okay on both sides so that's the important thing to remember the lateral branches they're going to give way to a couple different structures the first one you know you have a little tiny gland that sits on top of your kidneys a little tiny gland here that sits on top of your kidneys what is that little structure here called it's called the adrenal gland so what do you think this arteries that's going to go to the adrenal gland it's called the adrenal or suprarenal artery okay below that what's going to be just below the adrenal gland you're going to have the kidneys so what do you think that artery is going to be that's going and supplying this structure this will be the renal arteries and then in the developing embryo let's just be very specific you have gonads we don't know if they're gonna be ovaries or testes so we also have gonads these gonads have to have a particular arterial supply so what do you think that arterial supply is gonna be the gonadal arteries right and then respectively it would either become the ovarian or the testicular artery so these are called your gonadal arteries these are the brain these are gonna that's gonna become from the lateral branches so we know the dorsal outer branches we know the lateral branches what about that vitalin artery that's coming off the front going into the yolk sac well eventually that kind of the yolk sac will not be something that we're going to need in an adult and what happens is these arteries are going to supply the gut tube right so you know the gut tube you have the foregut you have the mid gut you have the hindgut we have particular arteries that supply all of those different portions we talked about the development of the digestive tract what is this one here at the top this is the celiac artery and this is going to give way to the this will supply blood to the fore gut then you have this next one so the vital artery breaks into three parts this right here is going to be the superior mesenteric artery this will supply the mid gut the mid gut and then again there's one last one and you guys should already kind of see this trend here again that's the mid gut this last one that the vital artery branches into is going to be called the inferior mesenteric artery and this will supply the hindgut boom we got an idea of what the vitalin artery will become go down you look here oh what the heck happened to the umbilical arteries they were coming off of this part just before it was bifurcating it's not there anymore well now i have something that i didn't see here before i have these little things that are coming off of what's called the common iliacs right so this would become your well abbreviate the cia right common iliac artery this is the common iliac artery any other common iliacs they split into internal and external so here we're going to kind of put a line here this will be your external iliac artery external iliac artery and then these coming off what do you think these are your internal iliac artery internal iliac artery your umbilical arteries they descend descend descend to sin and then kind of come off of the internal iliac arteries so coming off of the internal iliac arteries is going to be these two little structures here what are these called your umbilical arteries so this is going to be your right and left umbilical arteries now you're probably like well zach i thought we don't have umbilical arteries when you're when you become an adult you don't there's a remnant of the umbilical artery okay the adult remnant so some parts of it okay for the umbilical artery will be what's called the medial umbilical ligament so this will become a ligament later on throughout the actual process in the adult so this is called the adult remnant this is the adult remnant we'll talk about this a little bit later in the fetal circulation but there is a tiny little part of the umbilical artery that actually does can persist and this helps to form what's called the superior vesicle artery vesicle what that is a vesicle that's going to give some blood to the bladder so this will give a little bit of blood supply to the bladder so far we were able to see the entire formation of the arterial system because again we already know what's going to happen to the external iliac arteries what are these going to go down and supply your lower limbs right so this will come down and supply the lower limbs so now we've officially gone through the entire arterial system now that we've gone through this son of a gun let's go through the venous circulation all right ninja nurse so we covered the arterial system now through the venous circulation it's a teensy bit harder but we're gonna get through this so hold on to your huggies let's get into it the first thing that we got to do is kind of remind ourselves of that uh that heart tube right so we covered the outflow tracks going via the aortic and pulmonary circulation now what we got to do is cover this venous circulation so if you guys remember you had up here let's say this is the aortic sac then you have the truncus arteriosus then you have the bulbous cortis primitive ventricle primitive atria and then you have that sinus venosus and then that's giving way to some structures that are coming off of it okay this is where we're going to focus now so what i'm going to do is is i'm going to take and imagine that we're going to zoom in on this portion here and really go over all the stuff that's actually feeding into that and how that goes into the heart right let's do that first all right so when we look at this here this first structure that we're zooming in on here is the sinus venosus i'm just really enlarging it so this is called our sinus venosus now coming off the sinus phenosis you have two horns right this horn here is called you we're going to breathe rh your right horn this one coming off of this one is your left horn now there's a bunch of different veins that feed into this let's actually keep consistent with the color let's do blue here you have the veins coming from the outside here okay and we're actually going to kind of draw it like this because believe it or not this diagram is a teensy bit misleading so this is the first structures that are coming off on the outer parts of the sinus venosus okay this structure is here this one right here where they're kind of coming together this portion is called the right common cardinal vein this one over here where they're coming together is called the left common cardinal vein now the common means that there was something that actually had to come together to form a common cardinal vein and so this vein here which is going to be coming up and this one coming down this is called your right posterior cardinal vein this is called your right anterior cardinal vein this is called your left anterior cardinal vein and this is called your left posterior cardinal vein so the posterior cardinal veins anterior cardinal veins on both sides come together and form the common cardinal veins which empty into their respective horns which empty into the sinus venosus okay that's the first thing [Applause] the next one is you have structures that are going to come up just a little bit medial to that which are going to empty in here and these are going to be called your umbilical veins okay so these are going to be called your umbilical veins so this right here will be your right umbilical vein and this will be your left umbilical vein then the most medial portion here which will be right here is going to be your vitalin system your vitalin system so this would be what's called your right vitalin vein and this one here will be called your left vitalin vein we have the idea now of what this really should kind of like look like like when we start with this whole venous circulation what we have to do first is we're going to save the cardinal veins for last those are the hardest ones to go through what we're going to do is we're going to combine and talk about what these veins become first so we're going to go through the umbilical veins and the vitalin veins and talk about what they become are ready all right so before we actually dig into the vitalin system and the umbilical system the first thing that i want you guys to remember is that all of this circulation right these venous circulation pretty much is going to be right side dominant you're going to see that pretty consistently throughout the rest of these diagrams so what i want you to remember is a pretty consistent theme here is the left side will pretty much will shift to the right side okay so that i want you to kind of have that concept pretty ready to roll as i go through these actual circulations that most of the veins that are going to be coming on the left side will shift their supply or digress and pretty much will become a right side dominant venous system that's what i want you to remember all right so now that we understand that concept let's dig into these uh umbilical veins and vital and veins when we talk about this uh these two circuits these two venous circulations the vitalin and the umbilical venous system let's start with the vitalin system first so the first thing you gotta remember is that the vitalin system is coming from the yolk sac it's coming from that yolk sac all right so remember we have the umbilical arteries that we're going to the yolk sac you're going to have the umbilical veins that are going to be coming away from that yolk sac because everything's going to be going to the heart right so from the yolk sac you're going to have this vitellan system and again what are the two vitalin systems they're going to be the right and the left so we're going to call this the right vitalin vein and this is going to be the left vitalin vein what happens is these vital veins they kind of form a little plexus around the actual gi tract okay so they're going to move through the gi tract and form like a little plexus and then eventually what they're going to do is they're going to move from around that gi tract to the liver as they move into the liver they come into the liver and give off little capillaries called sinusoids these are tiny little like capillaries that are very permeable then what happens is these capillary systems they drain into kind of a hepatic vein and then this hepatic vein moves towards the sinus phenosis and this pink structure is representing these septum transverse them it'll kind of become the diaphragm right but again this will be your right side and this is going to be the left side so same thing hepatic sinusoids coming through here and eventually they're going to move up via the hepatic veins and then go to the sinus phonosis and then again this would be which side this would be the left side this little district of that left horn so this is the left phyton right vital and vein we give a specific name though to these actual vitelline veins as they're going from the liver to the sinus phenosis we're going to abbreviate this this one is called your right hepatocardiac channel and this one here is called the left hepatocardiac channel okay remember what i told you what do we preface everything with left side will pretty much digress and then it'll pretty much become right side dominant so you know what's going to happen to this left phytal and venous circulation it's going to start degressing okay so this whole lifetime system is going to start degressing all of this is going to digress and then as that whole vitalin system kind of digresses what do we say happens to that right vitiline system it'll become the prominent one so now more blood is going to be running through the right vitalin system so what does that mean it should be even having like a larger size then right it should be a larger size and because of you're going to have more blood coming just through that right vitalin system what do you call this kind of capillary network here that runs around all these kinds of different organs of the gi tract and the spleen and then takes it up to the liver and then eventually this will feed both of these kind of sinusoids what do you call all of these venous kind of circulations they give them a specific name you know there's a vein here that runs from the spleen and goes into this big structure here you know what they call this they call this the splenic vein you know the veins that are coming from your gut system particularly from the upper parts of your gut system what are those called this would be called your superior mesenteric vein you know the capillary system that's coming from the or the venous system that's coming from the lower part of the gut tube this will be your inferior mesenteric vein when the splenic vein the superior mesenteric vein and the inferior mesenteric vein come together what structure do they become the hepatic portal vein so now i'm going to have the hepatic portal vein the hepatic portal vein will then move into the liver and now again this is all right side that whole left side digressed all we have is just the remaining sinusoids that were formed by that left vitalin system that's all we've got left the hepatic portal vein will feed into this right that right vitalization will give away to the hepatic portal vein which will feed both vital the actual sinusoids now we had a left hepatocardiac channel that's gone all we have is a right so now this right one has to get plumper and bigger and it has to take blood from that actual sinusoids that were coming from the left vitalin system what are these two veins here called your hepatic veins so these are called your hepatic veins this would be your right one and this would be your left one when the hepatic veins come together and join they become one particular structure which is now longer called the right hepatocardiac channel it's called the inferior vena cava because guess what that inferior vena cava is now going to empty into the right horn into particularly the sinus venosus and then what does that sinuspinosis empty into the primitive atria and remember what we said in the development of the heart pretty much everything shifts to the right so really what part of the primitive atria is this sinus finishes emptying its blood into the right atrium we have just formed one part of the vitalin circulation so what do i want you to take away from the vital circulation the right vitalin vein circulation gives way to your hepatic portal system and the hepatic portion of the inferior vena cava pretty awesome now we have one other one okay you have the umbilical cord right so let's put here you have the placenta so now we're gonna have the placenta and then from the placenta you know you'll have what's called the umbilical cord right and through the umbilical cord you're gonna have your umbilical arteries and veins and all that good stuff running through remember what we said there's two veins right off the bat right off the bat i want you to remember that you have two vitelline veins but it's going to seem kind of contradictory remember i told you that pretty much on everything on the left side kind of digresses and goes to the right side not all the time so what i want you to remember is that the right umbilical vein and your left umbilical vein your right one pretty much digresses it'll come up and it'll kind of connect to these sinusoids and do the same thing but it's actually going to just pretty much digress so don't even worry about the right umbilical vein focus on this left umbilical vein it kind of does the same thing so let's track this guy up here okay it's going to run up here and as it runs up here it's going to do two things it's going to give some connections to the sinusoid so it'll kind of give a little bit of connections to the sinusoids but here's the big one that i want you to remember i'm actually going to change the color of this so that we're very particular here very very particular coming off of this left umbilical vein it will give sinusoidal branch but the main thing it's going to do is it's going to connect to this little bottom portion of the inferior vena cava and this is a very particular structure very particular that comes off the left umbilical vein and bridges to the inferior vena cava particularly around the area of the liver this is called the ductus venosus and the ductus venous is again it's a little channel it's kind of like a little shunt system but here's what's really cool about the duct tape is it has a lot of smooth muscle so it has the ability to kind of control the blood flow that's coming in through this circulation but the big thing is is that any of the blood right via that umbilical venous circulation that has to go to the heart guess where it has to go through through the ductus phthanosis to get into the inferior vena cava so what i want you to take away from the vitelline and umbilical venous system the right vital vein gives way to the hepatic portal circulation and hepatic portion of the inferior vena cava the left umbilical venous circulation will give way primarily to a little bit of sinusoidal connection but the big thing is the ductus phenosis which is a bridging connection between the left umbilical vein and the inferior vena cava boom we covered that circulation now the next thing you have to remember is zach you got you said that again the yolk sac won't actually be there anymore and neither will the umbilical veins and that's correct so pretty much after uh some time the yolk sac will pretty much digress and go away and then this whole kind of system here will pretty much digress okay what happens is when you cut the umbilical cord the umbilical vein will become a particular ligament that'll actually kind of connect around the liver and that is actually going to become eventually the adult remnant the adult remnant of the umbilical vein will lead to what's called the ligamentum teres okay the ligamentum teres so that's an important thing to remember so again the umbilical system and the vitalin system the big thing to remember what it becomes in the adult is vitelline is the hepatic portal inferior vena cava umbilical forms that connection between this the ductus venosus via the inferior vena cava but again eventually the actual source of the vitalin system and the source of the umbilical system primarily these veins they start to digress particularly thing to remember is the left umbilical vein will become the ligamentum teres and then this next thing eventually we'll talk about this later but the ductus venosus is a little channel again we don't want this umbilical vein to have some type of connection in the adult so eventually later on what happens is the ductus phenosis will also kind of become fibrotic and eventually become the adult remnant which is going to be called the ligamentum venosum okay so these are important things to remember when it comes to this actual venous circulation all right beautiful we cover the umbilical venous circulation and the vitalin system now let's cover the cardinal system all right engineers we've covered the vitalin system in the umbilical system now let's hit that cardinal system all right so again to recap it really quick just the cardinal system not the vitelli because we already covered the vital umbilical what do we have coming up here this is your right anterior cardinal this is your right posterior cardinal and then that point right there is called the right common cardinal vein this one right here same thing left anterior cardinal vein and then this one right here is going to be the left posterior cardinal vein and the point where they actually join together is called the left common cardinal vein the right common cardinal empties into the right horn left common cardinal empties into the left horn and they both feed into what's called this little structure called the sinus venosus we're clear on that right quickly abbreviated right anterior cardinal vein right posterior cardinal vein left posterior cardinal vein left anterior cardinal vein here's what i want you to remember the posterior cardinal veins bye-bye you gone we don't need you no more they're gonna disappear okay the left anterior cardinal vein what you're going to see next is that it's going to form a little bridging connection here it'll form a little bridge between the top part of the left anterior cardinal vein to the right anterior cardinal vein so everything above that bridging point okay so let's imagine you kept this thing going up this is going to be draining the head right everything above that will remain intact but this portion here below that chunting connection this will digress so now what are we going to have left over here all right watch this this should look familiar if this portion is gone that's not gonna be there the only thing that's gonna be here is just this top part of the left anterior cardinal vein all the other parts coming here is gone but now you're gonna also have the right anterior cardinal vein which will be coming down here and emptying into this kind of right horn okay now this left anterior cardinal vein what do we say this connection is where it's going to have here there's going to be like a little anastomosis if you will which is going to form between these structures here this should kind of start giving you a look of something in the adult all right watch this remember what we called the this portion here where you have that common cardinal vein we said that this is going to become the superior vena cava if you come up so this portion here will be the superior vena cava if you come up where you go at the level of where that anastomosis formed and above this is going to give way to your right brachiocephalic vein this will give way to your left brachiocephalic vein you know what the brachiocephalic veins come from above this you're going to have the internal jugular vein and then what's this thing the subclavian veins so this would be your internal jugular vein the right one this will be your left internal jugular vein this will be your left subclavian vein and this will be your right subclavian vein and so that whole anterior cardinal system particularly the right one is going to give way to this particular structure and the left anterior cardinal system will give way to the what left hand internal jugular vein left subclavian vein but primarily this bridging connection which is the left brachiocephalic vein we have the upper part of the venous circulation now we got to do that bottom part of the venous circulation we're probably like zach you just said that all these posterior cardinal veins just broke down what the heck happened what am i going to do with those not to worry my friends three systems develop right after they break down okay three systems develop right after they kind of break down and we're gonna have to go through each one of these and these are called you're particularly they're given particular types of cardinal names the first one here is called your supracardinal veins let's write them up here the first one here is called your supra cardinal veins the brown ones okay just below it it's called your sub cardinal veins and then the red ones just below that are going to be your sacral cardinal sacral cardinal veins right so you have your sacral cardinal veins your subcardinal veins and your supracardinal veins these are going to form after those posterior cardinal veins degenerate and these are going to become the structures that are going to be bringing blood from the abdominal cavity and from the lower limbs here we go remember what i told you this would be a left supracardinal right supracardinal here's very interesting the right supracardinal system okay and your left supracardinal system they're going to give off branches okay particularly like four five six and seven okay that's going to be off that left supra we'll put here supra cardinal vein so off of that left supracardinal vein it's going to have these branches four five six seven branches these are going to be going to the intercostal areas these are going to become your intercostal veins your left intercostal veins are going to come off of this left supercardinal vein the right supracardinal vein is going to have a lot more branches okay 11 10 9 8 7 6 5 4. this is your right okay this is actually going to be the right supracardinal vein now here's what happens you form a little anastomosis between the left supracardinal vein and the right supracardinal vein so so anastomosis is going to beautifully form between these structures okay and the blood is going to primarily flow in this direction now if the left supra opposed to the the left side of the supracardinal veins are draining the intercostal structures from these levels and then the right supracardinal veins on the actual side are draining these intercostal areas when they come together right they move up via this right supracardinal vein and empty into the superior vena cava what will become the superior vena cava you know what that venous circulation is called the one that comes actually behind and empties into the pure vena cava from the back this is called your a zygous system so this right supracardinal vein will give way to your azygos system so your azygos system will be derived from which one from the right supracardinal veins what is this system here coming from the left side shunting into the azygos system your hemiazygos system so this will become the hemi azygus system coming from what structures your left supracardinal veins and they're going to be shunting that blood into the right supracardinal system which will become the azygos system which empties into the superveniceva now next one subcardinal veins you have the right subcardinal vein and the left subcardinal vein alright so here's going to be your left we'll put sb so sub cardinal vein and then over here right sub cardinal vein the right subcardinal vein is going to give off three branches left subcardinal vein are going to give off three branches this is going to go and give a drain the adrenal gland the kidneys and the gonads same thing with the right subcardinal vein it'll drain blood from the adrenals it'll drain blood from the kidneys and it'll drain blood from the gonadal system now remember what i told you though the left side is primarily going to shift to which side the right side because we can't have two of these channels we have to have one of these channels that are imp that are basically draining blood from both adrenal glands both kidneys and both gonads that's what the inferior vena cava is so because of that what happens to this left sub cardinal vein it starts to degenerate and then the blood from that left subcardinal system starts doing what draining into the right subcardinal system and then this thing gets a little bit more plump and bigger and what is this part this is the renal portion of the inferior vena cava so what is this thing here what is the right sub cardinals the left subcardinal system is gone that one's bye-bye the right subcardinal system will give way to what structure here the renal portion of the inferior vena cava so this is going to give way to the renal portion of the inferior vena cava which is going to drain what structures adrenal renal and gonads good that might beg the question well zach where what was the other part of the inferior vena cava do you guys remember what it was what was the other part of the inferior vena cava that we made from the vitalin system the hepatic portion of the inferior ventricular so just above the renals if you were to kind of just draw this here what would be this portion here that would be running up here and coming and emptying into the right horn of the sinusoidal this would be that hepatic portion of the inferior vena cava which was derived from what system the right vitelline system so you kind of see how it's coming together right all right so now we're going to cover that sacrocardinal veins all right so you got over here again what would this one be here we'll put uh sc so right sacrocardinal vein and then over here you would have running the left sacral cardinal vein now what happens is at the bottom of these kind of sacrocardinal veins they continue to kind of form like these little like sprouts here like this okay and what happens is in the embryo this is taking blood from what structures this is bringing blood from the lower limbs right so if they're starting to form limb buds this is going to be taking blood from those lower limbs the witch system the sacral cardinal veins right lower limb would drain it to the right sacral cardinal and the left lower limb would drain into the left sacral cardinal veins remember what i told you though left shifts two right so what's going to happen is this left sacral cardinal vein is going to start degenerating at the portion just above that bend so now this portion is all going to degenerate and at the bend is where it's actually going to below that bending portion is where it'll start to shunt into the right sacral cardinal vein so again what happened to the left sacral cardinal vein it degenerated on only the portion below the bend would remain and shunt where into the right sacrocardial vein now the right sacrocardial vein has to get plumper bigger because it's taking blood from both limbs now what is this this is the uh lumbo sacral portion of the inferior vena cava we've covered all the parts there now all right so look at what we've done here think about this hepatic inferior vena cava came from the right vitalin vein the right subcardinal vein gave way to the renal portion of the inferior vena cava now the right subcardinal veins are going to give way to the sacral portion of the inferior vena cava oh man this is pretty cool right so now we have the sacral or some p some people even call it post renal so sacral portion or post renal portion of the inferior vena cava came from what structure here primarily the right sub cardinal vein okay that has finally finished our development of the vascular system all right ninja so in this video we talk about the development of the vascular system i hope it made sense and i hope that you guys did like it all right ninjas love you thank you thank you always for the support and care and as always until next time [Music] you