Prelab: Urinary System

welcome to this prelab video over the urinary system we'll be taking a look at the gross anatomy as well as the hystological structures of this fascinating system so the urinary system you probably think of it as uh the system that creates waste products and filters your blood but it not only is filtering your blood but the urinary system is also uh filtering your lymphatic uh fluids your your lymph and uh they are constantly uh the kidneys are constantly filtering uh your bloodstream again that plasma that's in your blood is continuous with the lymph of your lymphatic system and there are three basic components of the urinary system the yers the bladder itself and the urethra through which waste is removed collectively this is all called the urinary tract so from a gross anatomical standpoint the urinary system is rather simple we'll see that the magic of the urinary system is in the microscopic structures so we're taking a peak into the abdominal pelvic cavity but actually we're behind the abdominal pelvic cavity if you were to open up your abdominal pelvic area or even in your fetal pig you recognize that all the digestive organs have been removed here and even in your fetal pig dissection uh if you were to remove the intestines and the stomach and the liver you would not be able to directly uh access the kidneys they would be behind the perenium they would be behind that serious membrane so we see here the kidneys two kidneys left and right on the superior border of those kidneys are the adrenal glands you've seen the adrenal glands mentioned in the endocrine system also a connection with the autonomic nervous system it is the adrenal glands where one gets much of the adrenaline or the epinephrine that's released during sympathetic nervous system activation other things that are notable on this diagram that you already recognize from previous labs you can see on here the infu vnea and the aorta you know that the aort is splitting into the left and right common iliac arteries you can see that little internal iliac artery here and the continuation of the external iliac remember once you pass through the inguino ligament here that external ilc artery would now be referred to as a femoral artery okay what else do we see on here from previous Labs I see some muscles so let's talk about the muscles for a moment here remember the iliacus so we have the iliacus muscle here is the soaz major muscle and and then back here is the ql so we've seen those muscles previously so again we're just thinking about all the things we already are familiar with when we look into this region something we have not yet seen but we will see starting next week this is a representation of a female so we can see here the uterus and the fallopian tubes going off to the two ovaries and then finally there's something else related to the digestive system that I want you to get your eye on and that is right here so there is the esophagus breaking through the diaphragm and you can imagine that right about there is where that lower esophagal sphincter or that cardiac sphincter would be finally related to the vessels we saw last week here is the Celiac trunk those three vessels coming off here we can see the renal arteries bringing blood over to the kidneys and the renal veins returning the blood back related to the urinary system let's take a look here so pretty simple like I said we have the two kidneys left and right kidney the muscular tube that carries the urine down are the ERS down to the urinary bladder or just the bladder and then the uthra that allows that urine to be released from the body so in addition to removing waste products from the bloodstream and filtering the blood and the lymphatic fluids the urinary system is storing urine now this is a relatively short amount of time depending upon how large your bladder is about a liter of urine it could be more you're releasing that urine through the urethra but this fluid ID that you're losing or releasing from the urinary system is also really really important in regulating your overall blood volume so the kidneys are working with your cardiovascular system and under the control of a number of very important hormones that will become a important topic next semester in directing and regulating your overall blood pressure and then another another really important thing that the kidneys do is they actually help to regulate your red blood cell production your arthrite production and interestingly the hormone erythropoetin is released by the kidneys and you might see it abbreviated EPO but erythropoetin is released by the kidneys when blood oxygen levels go into the kidneys are low so when there's low oxygen levels the kidneys ramp up the production of epo this EPO travels through the blood heads to the bone marrow where it upregulates the production of red blood cells and this would then increase the hematocrite remember from blood that high altitudes uh have an effect on hematocrite so if you were to fly to Denver today um because of the lower atmospheric pressure your blood would sense less oxygen dissolved in the blood as a result your body would kick up its production of EPL and over the next 3 to five days your body would increase the number of red blood cells this would allow you to have more oxygen carrying capacity in your blood and would increase your hematocrit as the percentage of red blood cells rises in your blood couple of key words about the kidneys they and the rest of the urinary system said to be retroperitoneal behind the peritoneum kidneys have a hilum we saw hilum in the lungs as well that means that there's an indented area where all of the blood vessels nerves lymphatic structures go in and out of an organ so that indentation of the kidney is where the hilum is around the kidneys if you think about them they are critically important uh if you don't have the kidney function uh you can be dead in a few days from a lack of filtering of the blood and yet these two critically important organs are not as well protected as many other vital organs if you take a look at the anatomic position of the kidneys they are protected in part by the floating ribs but they don't have a tremendous amount of bony protection around them so there's some extra levels of connective tissue and fat layers around the kidneys to protect them so from Deep to superficial around the kidney itself there's a fibrous capsule or also called the renal capsule this is just a dense connected tissue that covers the outer surface of the kidney so when you're dissecting your kidney as you hold that kidney the outer uh layer of that kidney would be the fibrous capsule then around the kidney in your body would be a layer of fat the per nephric fat we know Perry means around so around the nefro around the kidney there's a layer of fat then there's going to be a renal fascia I think of this as a layer of Saran Wrap and this layer of Saran Wrap is what is adhering the kidneys to the posterior abdominal wall and then finally there's another layer of fat Paran nephric fat you know par means next to or near so this is fat that's near the kidney again these fat layers are helping to protect the overall structure of the kidney when you cut into the kidney you will see a cortical region the cortex and a medular region these are terms you're familiar with already from our conversation about the brain and the spinal cord and even bones when you look into the kidney uh there are some darker regions there's 8 to 15 of these renal pyramids found within the kidney now you won't see all of them at once but there are 8 to 15 of these pyramids within each of your two kidneys each of those pyramids has a tip or an apex that is pointing inward toward the minor cix recall from our vocab kaces or Helix is a cup like structure so these are the troughs or the collection collecting ducts that are going to receive the urine as it's produced so urine is going to flow through these kaces and drain from a minor CX into major kses and we'll see then how that urine will flow down the uers to the bladder so let's take a look at the bladder sorry I kidney so here we go so we've cut into the kidney and in this particular section I'm able to see 1 2 3 4 five six sections six of those pyramids are visible in this particular section keep in mind entire pyramids would be deep to this view or superficial to this particular cut the outer protective layer on the kidney would be that fibrous capsule and there is going to be a region referred to as a cortex and the cortex is the outer layer then the inner layer we see that the inner layer the medular region is composed of these column of these of these pyramids and these pyramids are separated by Reno columns so if you look between the pyramids you'll see these tall thin regions and those are the renal columns okay now as as urine is produced and we'll get into that in just a moment we're going to see that that urine is produced in the microscopic structures of these of the cortex and of the pyramid pyramids and that urine is going to drain into these collecting areas so here here is a minor cix here is a minor Kix here is a minor Kix and what you'll see is that these minor kses then merge into larger collecting areas referred to as a major KX all of the major kses so here's another major cix here and all of that urine is I'm going to collect into a large collecting area referred to as a renal pelvis so the renal pelvis change colors would be just the larger area here and then that urine would drip and travel down the urer heading to the bladder notice that there is the hilum again the hilum is the indented region of the kidney that allows everything to flow into it and here we see the renal artery the renal vein there would also be lymphatic and nervous structures uh that would also enter and leave in this General area of the kidney at the very tip at the very tip of each of these pyramids there is basically What's called the renal papill we've seen that word before imagine a little drip spout at the base of at the bottom of each of these Apes right each of the apexes apases there would be a little drip out called the renal pill so that would be at the border of the pyramid and the minor Kix under the microscope what are you going to see you're going to see uh within the kidney we are now in the cortex and in the cortex you have been told all along that there are tubules kidney tubules we'll come back and look at this picture in a moment but as I look here at this tubule we're going to see that the kidney is full of tubes and what I'm seeing is that this tube has a layer of simple cuboidal epithelium around it okay and as you look around this image you start to see that there are a lot of these regions with simple cuboidal epithelium that become pretty obvious as you look around we'll see that more in a moment we'll come back and look at this picture so we have a couple of things to keep track of in this conversation one um in the digestive system we talked about the flow of food through the digestive system we've discussed the flow of blood through the through the heart we have two things to keep track of in the kidney one we have the blood flow in and out of the kidney how is it that blood goes into the kidney how does it get filtered how does to then leave the kidney and then later on we'll deal with the flow of urine the production of urine and how it flows out of the urinary structures so let's start now with this conversation about blood flow into the kidney so here is the renal artery renal arter is bringing blood into the kidney like all arteries it's going to split and split and split the first split segmental arteries so we see that there are segmental arteries right the segmental arteries and then the segmental arteries are going to split now I want you to see what they do they split and they go up basically between the lobes okay they go up between the lobes so guess what between inter lowbar right inter lowbar arteries then those interlobar arteries do a big arch they do a big arch okay a Big Arc and those are the aru arteries again they're just getting smaller and more uh um they're separating the blood and bringing the blood into the microscopic structures of the kidney from the aru artery we're going to see these small arteries go into the lobe okay so interlobular arteries inter interlobular arteries and we'll pick up that story over here so here is the inter lobular artery and it's now going to come and go into a very small arterial called an aarant arterial now we know the word aarant right aarant aarant we know means toward so the AER arterial is bringing blood toward toward what toward the glus and recall that from our vocabulary glom means ball so scattered throughout the kidney are these little balls of capillaries so we see one here this ball of capillaries here's a ball of capillaries there's another GLA okay so the aarant arterial again I always overemphasize the aarant most folks would just call it the afferent arterial but the aparent arterial is going to bring that blood into this ball of capillaries called the glus Glarus is really the magical component of the kidney it is in the glus that the blood is going to be filtered we'll see this in a moment after the blood leaves out of the Glarus it's going to leave out an eant arterial right we know e means away from now already I hope that you're thinking to yourself wait a second Mac I thought that every time up until now when we saw blood oxygenated blood go into a capillary bed cuz I just said to you a moment ago that the glus is a capillary bed I thought that once blood went into a capillary bed that the blood came out into a Venus structure out of a blue structure and what we see is that red blood's going into the Glarus and red blood is leaving the Glarus what that tells us is that in the Glarus this is a capillary bed but it's not one where oxygen gets dropped off it is simply a capillary bed where molecules are filtered out so this is where the waste products from the blood are filtered out of the blood and they're going to end up in the urine as they're filtered through the kidneys the molecules that leave that capillary bed are going to leave out the eerin arterial now keep in mind at this point the kidney has not yet received any Oxygen so now the eerin arterial goes into a quote traditional capillary bad called the per tubular capillaries peritubular around the tubes so what you see here is that all around these tubes you see these capillaries wound around right so those are the peritubular capillaries notice that those peritubular capillaries in this drawing are going from red and they're becoming purplish and then leaving as blue again evidence that as blood is traveling through these particular capillaries you actually are losing oxygen okay so that's how the kidney is getting its oxygen from these peritubular capillaries then the blood is going to leave out and go through a series of veins and leave the kidney eventually leaving out the renal vein the renal vein would then travel back and Connect into the inferior vena and bring that Venus blood back to the right side of the heart while I have this picture here let me point out two things one there are two different types of tube like structures within the kidney and what we're seeing all we've dealt with so far in this picture is the blood flow through the kidney right so we come in through the renal artery go through these branching arteries down into the Ain arterial through the glus out the E faen arterial out to the peritubular capillaries and then back out through a series of veins but what we're going to see in a moment is that the kidney is also full of tube like structures called nephrons and there's two different types of nephrons and they're both shown here so let me Point them out now one is a cortical nefron all that means that the nefron is more up in the cortex in this diagram the line I'm drawing is the border between the more superficial cortex in the deeper medular region so the cortex over here on the left that I'm circling is all the way up in the cortex it's high in the cortex and so that's a cortical nefron the other type of nefron is juxa medary all that means is that it's next to the medulla notice that the tubing all this nefron tubing is down closer next to the medulla we'll see this again so I just as I just mentioned the blood flow to the kidney is critical for the kidneys to work your kidneys are receiving about oh 20 to 25% of all of the blood is traveling to your kidneys so they are getting a very large percentage of your blood this also should tell you that the kidneys are vital to life that the kidneys are constantly and without rest are filtering your blood 24/7 they are filtering your blood filtering your blood filtering your blood again that blood is going to travel into the renal artery as we described the plasma from that blood is going to be filtered through the glus that ball of capillaries the blood that is the the molecules that are filtered out are going to leave out with the urine and the blood that does not get filtered out is going to to leave through the eerin arterial and back into the blood supply again note that the glus is not a capillary involved with gas exchange but a capillary that allows for nutrient or waste exchanges so that's the flow of blood in and out of the kidney let's take a look at the amazing microscopic structures of the kid where all this magic happens and that's the nefron you've seen this term before functional unit remember that in the cardiovascular system the capillaries because that's where really all the magical exchange of things happens uh capillaries are called the functional units of the capillary system in the urinary system the nephron is the functional unit there are four basic parts of a nefron there is the renal cor pusle we'll see this again in a moment there is a section called a proximal convoluted tubal you might just hear the proximal tubal there is the nefron loop and finally there's a distal convoluted tubal together your two kidneys have about 2 and a half million of these nefron units and each of these nephrons if you could stretch it out would be about five 5 cm in length well 5 cm is about 2 in right so that means that between your two kidneys you have 5 million Ines of nefron tubing that gives you a real appreciation of just how much surface area is in your kidney that is dedicated to the job of filtering your blood as I mentioned earlier and you saw in the pictures nephrons come in two basic flavors there are cortical nephrons again the the tubing is higher up it's more toward the periphery the cortex of the kidney and you saw those per tubular capillaries wrapped around those cortical nefron the other type the jux to medary nephrons are deeper they lie next to the medulla and there's another capillary bed they are called the Vasa recta from your vocab you're seeing that vas means vessel and you already know that recta means straight so as we look back at the juxa medular nefron here's that jux medular nefron and this group of vessels right here the vas erecta what you're seeing is a capillary bed and it goes straight down deep into the medulla and so Vasa recta straight right it's a very straight vessel goes straight down with the loop that we'll describe here in a moment notice you don't see the Vasa recta over here on the cortical NE the cortical [Music] nephrons so I'm going to go through each part of the nefron dissect this a little bit so the first part is the renal cor pusle uh this is composed of two parts there's the glus we've seen that before that's that ball of capillaries and it is contained within a capsule named after a person the Bowman's capsule you may also just see it called the glomular capsule now the special thing about this glus is that these capillaries are leaky right they're full of little holes we'll see these little holes in a moment and those little holes are called fenestrations we say that these capillaries are fenestrated and these holes act as a filter paper type of idea so here we have capillaries that have holes in them and we've already discussed previously that capillaries are very weak very fragile structures and to help with this filtering process and to give these delicate capillar a little bit more structure there are cells that are going to wrap around these glomular capillaries called phocytes These are cells with foot like right podiatrist footlik structures they're going to wrap around and help support the filtration of these glomular capillaries let's take a look at that so we are looking at just a small fraction of a glus here are two of those capillaries so we're looking at one capillary here right and another one here and on top we see this here's this the nucleus of the Poo site and we see that it has these long extensions but it also has these really cool extensions that help to embrace and and circle the capillaries these phocytes and these pedestals these extensions have what is what ends up being filtration slits okay so what we see here is that as molecules are passing through the glus as blood passes through the glus only small molecules are going to be able to number one get out of these little fenestrations so I'm circling the fenestrations now these little holes right little holes in the Capers of the fenestrations so only small molecules can fit through those little holes and then those small molecules must also make their way between these filtration slits so really what you have here is two layers of filter paper you have the fenestrations of the capillary and you have the filtration slits of the phocytes now if I were to draw a red blood cell in these capill recall that a capill is only about 8 to 10 microns so if this is 8 to 10 microns from edge to edge this capillary remember that red blood cells are 7.5 microns so if I were to draw a red blood cell in here right there is no way that a red blood cell is going to be able to leak through these little openings these penetrations pretty tight squeeze isn't it so keep in mind that as blood is traveling through the glami plural Glarus glami plural it is not blood cells that are going to leak out and get into the urine it's just going to be the small molecules glucose electrolytes Ura other waste products that are necessary to get rid of okay only the smallest molecules are going to get through as you look over here at this electron micro micrograph I think it's just an amazing picture of just the intricacy and the beauty of this arrangement of the poto sites the pedestals and these filtration slits so let's put this all together as blood travels again into the renal artery and through the segmental artery and the interlobular and all of those branches blood will eventually enter into the aarant arterial keep in mind there are [Music] 200 you know there's Millions right of these uh aarin arterials within your two kidneys so blood is going to come in the arrow tells us this so the blood's coming in it's going to come into these fenestrated capillaries of the glus the small waste products that are in the plasma are going going to diffuse or filtrate out of these capillaries those molecules are going to accumulate in this Bowman space and that fluid is then going to make its way down this direction as part of the proximal convoluted tubal now whatever does not get filtered out is going to leave the glus out the eant arterial again red blood in Red Blood Out o oxygen has not been dropped off just waste products after the blood has gone into the glus and molecules have been filtered out through those filtration slits and the fenestrated capillaries that filtrate that fluid it's not urine yet that filtrate is going to make its way into the proximal convoluted tubal all this word means is that it's a tube that is convoluted Twisted that is proximal closer to the point of attachment so we know all those words and there's something happening here in the proximal convoluted tubal we're going to say that the process of reabsorption occurs many molecules will be reabsorbed things like glucose and amino acids and other useful electrolytes will be reabsorbed will be taken back up by the blood system we would not want to lose all those useful molecules into our urine also about 23d 60 to 65% of all the water in that fluid will be reabsorbed by the process of osmosis okay now where are those molecules going where is that glucose and those amino acids and all that water going well those molecules are going to enter right back into capillaries remember those peritubular capillaries they were wrapped around the tubes that's where those molecules are going to be reabsorbed back into the overall cardiovascular system the molecules that have not been reabsorbed are going to continue through the nephron loop and the nefron loop is also called The Loop of Henley after the person that described it it's going to take a deep downward Bend into the medular region and then a backward upward swing so you have the descending Limb and the a sending limb and I'm not going to go into what's happening there just know that as those molecules as that filtrate goes through the nefron loop that there are modifications being made and that this fluid is becoming more and more concentrated as it travels through these structures finally the filtrate is going to make it back into the distal compilated tubul right series of tubes that are twisted found on the far side right on the distal side and the primary job of the distal convoluted tubal is a process referred to as secretion we discussing this in lecture the number one molecule that I want you thinking about that is secreted is H+ hydrogen ions okay and and the reason I want you thinking about this is that we are constantly making acids constantly making acids our our metabolism at as we break down molecules for energy our body is making acid and we have to get rid of that acid somehow so we'll see that uh the distal convoluted tubal's job is to do the process of secretion now that word is not what it seems to be secretion is the opposite of reabsorption we'll talk about this in a minute and you're going to see in lecture a little bit of a conversation about a couple hormones aldosterone and antidiuretic hormone ADH it's not a concern here for lab all I really want to talk about are the structures of the urinary system but in lecture you will hear me discuss aldosterone and ADH just a little bit and then that will be a major component of your learning in physiology so imagine that we have taken here a pyramid right so here's a pyramid taken out of this kidney we now see this pyramid shown here it's been very simplified we're only seeing a couple of nephrons um this nefron right here most of the tubing is up high this is a cortical nefron this one the tubing is a little bit lower and there is a very long and deep Loop of Henley so on this side this is a juxa medular nefron and on this side this is a cortical nefron just to see that again they do different jobs uh and when you get into the physiology of this you'll appreciate that more but I just want to point out there's two different types of nephrons so let's follow the the the the story here so blood would come into the aent material into the Glarus here it would be filtered that which does not get filtered out would leave out the eant right out the eant arterial what does go into the Glarus and gets filtered through would become part of the filtrate and that filtrate is going to start traveling through the proximal convoluted tubule as it passes through the convoluted tubal molecules are being re absorbed taken out of it useful molecules will be taken out of it it will then continue down the loop of Henley come back up into the distal convoluted tubal the job of the distal convoluted tubal is secretion talk about that again in a moment and then whatever has is left now in this fluid this filtrate we'll find its way and dump into a collecting duct notice that the collecting duck is receiving urine from many nephrons so this is a simplified picture many nephrons are dumping their urine into this collecting duct at the very end there is that renal Pilla again imagine a little drip spout here that is releasing the urine and then down here collecting this urine would be the minor Kix once the fluid gets into the collecting duct it's essentially urine there is a one last chance for the body to modify that fluid and in the collecting ducts if a person is well hydrated or if you're walking around and you're drinking and you're well hydrated um then everything that goes into the duct will simply make its way down to the bladder and be released however if you are dehydrated the body is going to try to conserve water and it will do its best to concentrate the urine even more and that hormone ADH will play a part in this concentrating of the urine again we'll deal with that more in lecture so now we've talked very briefly about how the kidney is filtering the blood filtering out those waste products how those waste products make their way through the convoluted tubes through the nefron structure and then that concentrated fluid will be released to the bladder how does that work so as the urine is made which is being made 24/7 Around the Clock the bladder is going to be ready to receive that fluid it's an expandable muscular container um and in the female the blood is in contact with the uterus and in males it is in contact with the rectum as well as the prostate gland the bladder as well as the kidneys retrop peronal when the bladder is empty the bladder sort of looks like an upside down pyramid as it fills it assumes more of an oval shapee inside the bladder there's an area um called the trigone this is an area it's an imaginary area if you will but there are two openings for where the uers drop the fluid into the urine and then there's the opening for the urethra so you'll see sort of a three opening area triangle right trigone um and this you will see um in the in the bladder pictures in a moment basically the bladder acts as the funnel and as the bladder fills it starts to push on the sphincters that will give you then the urge to uh go to the go to the restroom the bladder has four tunics around it boy these look awfully familiar uh looks a lot like what we saw in the digestive structures the mucosa sub mucosa muscularis and the adventia so taking a look at this here are the urits coming down from the kidneys this is the peritoneum right we know the peritoneum that membrane that serus membrane that creates the abdominal pelvic uh cavity the bladder is below that inside the bladder there's rug sort of like what we see in the stomachs or a roughened area here we see two openings so this urine is is coming down and enters into the bladder here then here's the opening for the urethra so this is that triangular trigone area the wall of the bladder is a muscle the detrusor muscle we call to Truse means to force away we saw that in our vocabulary and as the bladder fills it begins to push here and right here there are smooth muscles uh the internal urethal sphincter as those get stretched it's going to give you the urge to go to the restroom and then further down there's the external urethal sphincter these are voluntary skeletal muscles over which you hopefully have control this is showing a female um bladder and right here is a layer of muscle we're going to see this in a moment but this is called the urogenital diaphragm uh when you think of the diaphragm you think of something that separates so this layer of muscle One Way think about sort of the pelvic floor is what separates the internal from the external structure we'll see it in the mail in a moment as well recall too that the inside of the bladder is lined by transitional epithelia so the urethra then is the way by which the urine leaves the bladder and it is surrounded by smooth muscle that will help Propel that urine out of the body two sphincters that I mentioned already the internal sphincter and the external sphincter the internal sphincter again is smooth muscle involuntary and then the external sphincter is voluntary basically this is your toilet training muscle right when you're training children how to hold themselves it's the external sphincter that the child is learning to control let's take a look again at this situation we've got the urethal openings sorry the urer openings and then the urethal opening here internal sphincter smooth muscle here external sphincter here this muscle again on both sides would be considered the urogenital diaphragm and again this would be a female uthra in the male the urethra is both a passageway for urine and a passageway for semen it's a longer structure there are three parts to the male urethra prosthetic urethra the part that passes through the prostate itself a relatively short region called the membranous urethra this region is right there at that urogenital diaphragm layer and then the spongy urethra is passing through the spongy or erectile tissues of the penis the spongy urethra other books will call the penile urethra so looking at these structures so the bladder is the same so here are those openings for the ERS and here is the uthal opening but what we see in the mail now is the prostate gland so the prostate gland is shown here this Walnut shaped gland the urethra passes through the center of that prostate gland so in the blue area that's prosthetic urethra this yellowish green area is the membranous urethra so there is the urogenital diaphragm that muscular wall and then here in purple is the spongy or the p urethra passing through the erectile spongy regions of the penis next week we'll discuss the male reproductive system and we'll study more about those erectile tissues so what can go wrong with prostate if the prostate begins to enlarge which is a pretty typical aging phenomenon in men couple things happen one the prostate can start to squeeze down and make the Lumen make the passageway more restricted so what that does is it makes urination uh not be as complete uh the the the flow of urine is reduced okay the other thing that can happen though is as a prostate enlarges it can push up on the smooth muscle and that can give the guy the urge to go even though he doesn't have to go right so it's that pushing on that smooth muscle of the internal sphincter that gives one the urge to go so as the bladder uh the bladder may not be full but because of the enlarged prostate the guy is getting this constant feeling of having to go having to go and then they get there and there's nothing happening so those are some of the uh side effects of an enlarged prostate so today um in addition to looking over all of the structures of the kidney you're also going to be dissecting a kidney you'll find some lovely images in your lab Atlas but here is a uh kidney that's been opened up next to a lovely labeled kidney so it will be important that you can identify the cortex the medulla that you can recognize those pyramids within the medulla that you can recognize the minor and major koses the renal pelvis you should be able to find the urer coming off the kidney you should also on most specimens be able to see the renal artery and the renal vein you'll be able to see the renal columns in between the pyramids and you'll recognize that the outer container the outer layer of the kidney itself is that fibrous capsule

welcome to this prelab video over the urinary system we&#39;ll be taking a look at the gross anatomy as well as the hystological structures of this fascinating system so the urinary system you probably think of it as uh the system that creates waste products and filters your blood but it not only is filtering your blood but the urinary system is also uh filtering your lymphatic uh fluids your your lymph and uh they are constantly uh the kidneys are constantly filtering uh your bloodstream again that plasma that&#39;s in your blood is continuous with the lymph of your lymphatic system and there are three basic components of the urinary system the yers the bladder itself and the urethra through which waste is removed collectively this is all called the urinary tract so from a gross anatomical standpoint the urinary system is rather simple we&#39;ll see that the magic of the urinary system is in the microscopic structures so we&#39;re taking a peak into the abdominal pelvic cavity but actually we&#39;re behind the abdominal pelvic cavity if you were to open up your abdominal pelvic area or even in your fetal pig you recognize that all the digestive organs have been removed here and even in your fetal pig dissection uh if you were to remove the intestines and the stomach and the liver you would not be able to directly uh access the kidneys they would be behind the perenium they would be behind that serious membrane so we see here the kidneys two kidneys left and right on the superior border of those kidneys are the adrenal glands you&#39;ve seen the adrenal glands mentioned in the endocrine system also a connection with the autonomic nervous system it is the adrenal glands where one gets much of the adrenaline or the epinephrine that&#39;s released during sympathetic nervous system activation other things that are notable on this diagram that you already recognize from previous labs you can see on here the infu vnea and the aorta you know that the aort is splitting into the left and right common iliac arteries you can see that little internal iliac artery here and the continuation of the external iliac remember once you pass through the inguino ligament here that external ilc artery would now be referred to as a femoral artery okay what else do we see on here from previous Labs I see some muscles so let&#39;s talk about the muscles for a moment here remember the iliacus so we have the iliacus muscle here is the soaz major muscle and and then back here is the ql so we&#39;ve seen those muscles previously so again we&#39;re just thinking about all the things we already are familiar with when we look into this region something we have not yet seen but we will see starting next week this is a representation of a female so we can see here the uterus and the fallopian tubes going off to the two ovaries and then finally there&#39;s something else related to the digestive system that I want you to get your eye on and that is right here so there is the esophagus breaking through the diaphragm and you can imagine that right about there is where that lower esophagal sphincter or that cardiac sphincter would be finally related to the vessels we saw last week here is the Celiac trunk those three vessels coming off here we can see the renal arteries bringing blood over to the kidneys and the renal veins returning the blood back related to the urinary system let&#39;s take a look here so pretty simple like I said we have the two kidneys left and right kidney the muscular tube that carries the urine down are the ERS down to the urinary bladder or just the bladder and then the uthra that allows that urine to be released from the body so in addition to removing waste products from the bloodstream and filtering the blood and the lymphatic fluids the urinary system is storing urine now this is a relatively short amount of time depending upon how large your bladder is about a liter of urine it could be more you&#39;re releasing that urine through the urethra but this fluid ID that you&#39;re losing or releasing from the urinary system is also really really important in regulating your overall blood volume so the kidneys are working with your cardiovascular system and under the control of a number of very important hormones that will become a important topic next semester in directing and regulating your overall blood pressure and then another another really important thing that the kidneys do is they actually help to regulate your red blood cell production your arthrite production and interestingly the hormone erythropoetin is released by the kidneys and you might see it abbreviated EPO but erythropoetin is released by the kidneys when blood oxygen levels go into the kidneys are low so when there&#39;s low oxygen levels the kidneys ramp up the production of epo this EPO travels through the blood heads to the bone marrow where it upregulates the production of red blood cells and this would then increase the hematocrite remember from blood that high altitudes uh have an effect on hematocrite so if you were to fly to Denver today um because of the lower atmospheric pressure your blood would sense less oxygen dissolved in the blood as a result your body would kick up its production of EPL and over the next 3 to five days your body would increase the number of red blood cells this would allow you to have more oxygen carrying capacity in your blood and would increase your hematocrit as the percentage of red blood cells rises in your blood couple of key words about the kidneys they and the rest of the urinary system said to be retroperitoneal behind the peritoneum kidneys have a hilum we saw hilum in the lungs as well that means that there&#39;s an indented area where all of the blood vessels nerves lymphatic structures go in and out of an organ so that indentation of the kidney is where the hilum is around the kidneys if you think about them they are critically important uh if you don&#39;t have the kidney function uh you can be dead in a few days from a lack of filtering of the blood and yet these two critically important organs are not as well protected as many other vital organs if you take a look at the anatomic position of the kidneys they are protected in part by the floating ribs but they don&#39;t have a tremendous amount of bony protection around them so there&#39;s some extra levels of connective tissue and fat layers around the kidneys to protect them so from Deep to superficial around the kidney itself there&#39;s a fibrous capsule or also called the renal capsule this is just a dense connected tissue that covers the outer surface of the kidney so when you&#39;re dissecting your kidney as you hold that kidney the outer uh layer of that kidney would be the fibrous capsule then around the kidney in your body would be a layer of fat the per nephric fat we know Perry means around so around the nefro around the kidney there&#39;s a layer of fat then there&#39;s going to be a renal fascia I think of this as a layer of Saran Wrap and this layer of Saran Wrap is what is adhering the kidneys to the posterior abdominal wall and then finally there&#39;s another layer of fat Paran nephric fat you know par means next to or near so this is fat that&#39;s near the kidney again these fat layers are helping to protect the overall structure of the kidney when you cut into the kidney you will see a cortical region the cortex and a medular region these are terms you&#39;re familiar with already from our conversation about the brain and the spinal cord and even bones when you look into the kidney uh there are some darker regions there&#39;s 8 to 15 of these renal pyramids found within the kidney now you won&#39;t see all of them at once but there are 8 to 15 of these pyramids within each of your two kidneys each of those pyramids has a tip or an apex that is pointing inward toward the minor cix recall from our vocab kaces or Helix is a cup like structure so these are the troughs or the collection collecting ducts that are going to receive the urine as it&#39;s produced so urine is going to flow through these kaces and drain from a minor CX into major kses and we&#39;ll see then how that urine will flow down the uers to the bladder so let&#39;s take a look at the bladder sorry I kidney so here we go so we&#39;ve cut into the kidney and in this particular section I&#39;m able to see 1 2 3 4 five six sections six of those pyramids are visible in this particular section keep in mind entire pyramids would be deep to this view or superficial to this particular cut the outer protective layer on the kidney would be that fibrous capsule and there is going to be a region referred to as a cortex and the cortex is the outer layer then the inner layer we see that the inner layer the medular region is composed of these column of these of these pyramids and these pyramids are separated by Reno columns so if you look between the pyramids you&#39;ll see these tall thin regions and those are the renal columns okay now as as urine is produced and we&#39;ll get into that in just a moment we&#39;re going to see that that urine is produced in the microscopic structures of these of the cortex and of the pyramid pyramids and that urine is going to drain into these collecting areas so here here is a minor cix here is a minor Kix here is a minor Kix and what you&#39;ll see is that these minor kses then merge into larger collecting areas referred to as a major KX all of the major kses so here&#39;s another major cix here and all of that urine is I&#39;m going to collect into a large collecting area referred to as a renal pelvis so the renal pelvis change colors would be just the larger area here and then that urine would drip and travel down the urer heading to the bladder notice that there is the hilum again the hilum is the indented region of the kidney that allows everything to flow into it and here we see the renal artery the renal vein there would also be lymphatic and nervous structures uh that would also enter and leave in this General area of the kidney at the very tip at the very tip of each of these pyramids there is basically What&#39;s called the renal papill we&#39;ve seen that word before imagine a little drip spout at the base of at the bottom of each of these Apes right each of the apexes apases there would be a little drip out called the renal pill so that would be at the border of the pyramid and the minor Kix under the microscope what are you going to see you&#39;re going to see uh within the kidney we are now in the cortex and in the cortex you have been told all along that there are tubules kidney tubules we&#39;ll come back and look at this picture in a moment but as I look here at this tubule we&#39;re going to see that the kidney is full of tubes and what I&#39;m seeing is that this tube has a layer of simple cuboidal epithelium around it okay and as you look around this image you start to see that there are a lot of these regions with simple cuboidal epithelium that become pretty obvious as you look around we&#39;ll see that more in a moment we&#39;ll come back and look at this picture so we have a couple of things to keep track of in this conversation one um in the digestive system we talked about the flow of food through the digestive system we&#39;ve discussed the flow of blood through the through the heart we have two things to keep track of in the kidney one we have the blood flow in and out of the kidney how is it that blood goes into the kidney how does it get filtered how does to then leave the kidney and then later on we&#39;ll deal with the flow of urine the production of urine and how it flows out of the urinary structures so let&#39;s start now with this conversation about blood flow into the kidney so here is the renal artery renal arter is bringing blood into the kidney like all arteries it&#39;s going to split and split and split the first split segmental arteries so we see that there are segmental arteries right the segmental arteries and then the segmental arteries are going to split now I want you to see what they do they split and they go up basically between the lobes okay they go up between the lobes so guess what between inter lowbar right inter lowbar arteries then those interlobar arteries do a big arch they do a big arch okay a Big Arc and those are the aru arteries again they&#39;re just getting smaller and more uh um they&#39;re separating the blood and bringing the blood into the microscopic structures of the kidney from the aru artery we&#39;re going to see these small arteries go into the lobe okay so interlobular arteries inter interlobular arteries and we&#39;ll pick up that story over here so here is the inter lobular artery and it&#39;s now going to come and go into a very small arterial called an aarant arterial now we know the word aarant right aarant aarant we know means toward so the AER arterial is bringing blood toward toward what toward the glus and recall that from our vocabulary glom means ball so scattered throughout the kidney are these little balls of capillaries so we see one here this ball of capillaries here&#39;s a ball of capillaries there&#39;s another GLA okay so the aarant arterial again I always overemphasize the aarant most folks would just call it the afferent arterial but the aparent arterial is going to bring that blood into this ball of capillaries called the glus Glarus is really the magical component of the kidney it is in the glus that the blood is going to be filtered we&#39;ll see this in a moment after the blood leaves out of the Glarus it&#39;s going to leave out an eant arterial right we know e means away from now already I hope that you&#39;re thinking to yourself wait a second Mac I thought that every time up until now when we saw blood oxygenated blood go into a capillary bed cuz I just said to you a moment ago that the glus is a capillary bed I thought that once blood went into a capillary bed that the blood came out into a Venus structure out of a blue structure and what we see is that red blood&#39;s going into the Glarus and red blood is leaving the Glarus what that tells us is that in the Glarus this is a capillary bed but it&#39;s not one where oxygen gets dropped off it is simply a capillary bed where molecules are filtered out so this is where the waste products from the blood are filtered out of the blood and they&#39;re going to end up in the urine as they&#39;re filtered through the kidneys the molecules that leave that capillary bed are going to leave out the eerin arterial now keep in mind at this point the kidney has not yet received any Oxygen so now the eerin arterial goes into a quote traditional capillary bad called the per tubular capillaries peritubular around the tubes so what you see here is that all around these tubes you see these capillaries wound around right so those are the peritubular capillaries notice that those peritubular capillaries in this drawing are going from red and they&#39;re becoming purplish and then leaving as blue again evidence that as blood is traveling through these particular capillaries you actually are losing oxygen okay so that&#39;s how the kidney is getting its oxygen from these peritubular capillaries then the blood is going to leave out and go through a series of veins and leave the kidney eventually leaving out the renal vein the renal vein would then travel back and Connect into the inferior vena and bring that Venus blood back to the right side of the heart while I have this picture here let me point out two things one there are two different types of tube like structures within the kidney and what we&#39;re seeing all we&#39;ve dealt with so far in this picture is the blood flow through the kidney right so we come in through the renal artery go through these branching arteries down into the Ain arterial through the glus out the E faen arterial out to the peritubular capillaries and then back out through a series of veins but what we&#39;re going to see in a moment is that the kidney is also full of tube like structures called nephrons and there&#39;s two different types of nephrons and they&#39;re both shown here so let me Point them out now one is a cortical nefron all that means that the nefron is more up in the cortex in this diagram the line I&#39;m drawing is the border between the more superficial cortex in the deeper medular region so the cortex over here on the left that I&#39;m circling is all the way up in the cortex it&#39;s high in the cortex and so that&#39;s a cortical nefron the other type of nefron is juxa medary all that means is that it&#39;s next to the medulla notice that the tubing all this nefron tubing is down closer next to the medulla we&#39;ll see this again so I just as I just mentioned the blood flow to the kidney is critical for the kidneys to work your kidneys are receiving about oh 20 to 25% of all of the blood is traveling to your kidneys so they are getting a very large percentage of your blood this also should tell you that the kidneys are vital to life that the kidneys are constantly and without rest are filtering your blood 24/7 they are filtering your blood filtering your blood filtering your blood again that blood is going to travel into the renal artery as we described the plasma from that blood is going to be filtered through the glus that ball of capillaries the blood that is the the molecules that are filtered out are going to leave out with the urine and the blood that does not get filtered out is going to to leave through the eerin arterial and back into the blood supply again note that the glus is not a capillary involved with gas exchange but a capillary that allows for nutrient or waste exchanges so that&#39;s the flow of blood in and out of the kidney let&#39;s take a look at the amazing microscopic structures of the kid where all this magic happens and that&#39;s the nefron you&#39;ve seen this term before functional unit remember that in the cardiovascular system the capillaries because that&#39;s where really all the magical exchange of things happens uh capillaries are called the functional units of the capillary system in the urinary system the nephron is the functional unit there are four basic parts of a nefron there is the renal cor pusle we&#39;ll see this again in a moment there is a section called a proximal convoluted tubal you might just hear the proximal tubal there is the nefron loop and finally there&#39;s a distal convoluted tubal together your two kidneys have about 2 and a half million of these nefron units and each of these nephrons if you could stretch it out would be about five 5 cm in length well 5 cm is about 2 in right so that means that between your two kidneys you have 5 million Ines of nefron tubing that gives you a real appreciation of just how much surface area is in your kidney that is dedicated to the job of filtering your blood as I mentioned earlier and you saw in the pictures nephrons come in two basic flavors there are cortical nephrons again the the tubing is higher up it&#39;s more toward the periphery the cortex of the kidney and you saw those per tubular capillaries wrapped around those cortical nefron the other type the jux to medary nephrons are deeper they lie next to the medulla and there&#39;s another capillary bed they are called the Vasa recta from your vocab you&#39;re seeing that vas means vessel and you already know that recta means straight so as we look back at the juxa medular nefron here&#39;s that jux medular nefron and this group of vessels right here the vas erecta what you&#39;re seeing is a capillary bed and it goes straight down deep into the medulla and so Vasa recta straight right it&#39;s a very straight vessel goes straight down with the loop that we&#39;ll describe here in a moment notice you don&#39;t see the Vasa recta over here on the cortical NE the cortical [Music] nephrons so I&#39;m going to go through each part of the nefron dissect this a little bit so the first part is the renal cor pusle uh this is composed of two parts there&#39;s the glus we&#39;ve seen that before that&#39;s that ball of capillaries and it is contained within a capsule named after a person the Bowman&#39;s capsule you may also just see it called the glomular capsule now the special thing about this glus is that these capillaries are leaky right they&#39;re full of little holes we&#39;ll see these little holes in a moment and those little holes are called fenestrations we say that these capillaries are fenestrated and these holes act as a filter paper type of idea so here we have capillaries that have holes in them and we&#39;ve already discussed previously that capillaries are very weak very fragile structures and to help with this filtering process and to give these delicate capillar a little bit more structure there are cells that are going to wrap around these glomular capillaries called phocytes These are cells with foot like right podiatrist footlik structures they&#39;re going to wrap around and help support the filtration of these glomular capillaries let&#39;s take a look at that so we are looking at just a small fraction of a glus here are two of those capillaries so we&#39;re looking at one capillary here right and another one here and on top we see this here&#39;s this the nucleus of the Poo site and we see that it has these long extensions but it also has these really cool extensions that help to embrace and and circle the capillaries these phocytes and these pedestals these extensions have what is what ends up being filtration slits okay so what we see here is that as molecules are passing through the glus as blood passes through the glus only small molecules are going to be able to number one get out of these little fenestrations so I&#39;m circling the fenestrations now these little holes right little holes in the Capers of the fenestrations so only small molecules can fit through those little holes and then those small molecules must also make their way between these filtration slits so really what you have here is two layers of filter paper you have the fenestrations of the capillary and you have the filtration slits of the phocytes now if I were to draw a red blood cell in these capill recall that a capill is only about 8 to 10 microns so if this is 8 to 10 microns from edge to edge this capillary remember that red blood cells are 7.5 microns so if I were to draw a red blood cell in here right there is no way that a red blood cell is going to be able to leak through these little openings these penetrations pretty tight squeeze isn&#39;t it so keep in mind that as blood is traveling through the glami plural Glarus glami plural it is not blood cells that are going to leak out and get into the urine it&#39;s just going to be the small molecules glucose electrolytes Ura other waste products that are necessary to get rid of okay only the smallest molecules are going to get through as you look over here at this electron micro micrograph I think it&#39;s just an amazing picture of just the intricacy and the beauty of this arrangement of the poto sites the pedestals and these filtration slits so let&#39;s put this all together as blood travels again into the renal artery and through the segmental artery and the interlobular and all of those branches blood will eventually enter into the aarant arterial keep in mind there are [Music] 200 you know there&#39;s Millions right of these uh aarin arterials within your two kidneys so blood is going to come in the arrow tells us this so the blood&#39;s coming in it&#39;s going to come into these fenestrated capillaries of the glus the small waste products that are in the plasma are going going to diffuse or filtrate out of these capillaries those molecules are going to accumulate in this Bowman space and that fluid is then going to make its way down this direction as part of the proximal convoluted tubal now whatever does not get filtered out is going to leave the glus out the eant arterial again red blood in Red Blood Out o oxygen has not been dropped off just waste products after the blood has gone into the glus and molecules have been filtered out through those filtration slits and the fenestrated capillaries that filtrate that fluid it&#39;s not urine yet that filtrate is going to make its way into the proximal convoluted tubal all this word means is that it&#39;s a tube that is convoluted Twisted that is proximal closer to the point of attachment so we know all those words and there&#39;s something happening here in the proximal convoluted tubal we&#39;re going to say that the process of reabsorption occurs many molecules will be reabsorbed things like glucose and amino acids and other useful electrolytes will be reabsorbed will be taken back up by the blood system we would not want to lose all those useful molecules into our urine also about 23d 60 to 65% of all the water in that fluid will be reabsorbed by the process of osmosis okay now where are those molecules going where is that glucose and those amino acids and all that water going well those molecules are going to enter right back into capillaries remember those peritubular capillaries they were wrapped around the tubes that&#39;s where those molecules are going to be reabsorbed back into the overall cardiovascular system the molecules that have not been reabsorbed are going to continue through the nephron loop and the nefron loop is also called The Loop of Henley after the person that described it it&#39;s going to take a deep downward Bend into the medular region and then a backward upward swing so you have the descending Limb and the a sending limb and I&#39;m not going to go into what&#39;s happening there just know that as those molecules as that filtrate goes through the nefron loop that there are modifications being made and that this fluid is becoming more and more concentrated as it travels through these structures finally the filtrate is going to make it back into the distal compilated tubul right series of tubes that are twisted found on the far side right on the distal side and the primary job of the distal convoluted tubal is a process referred to as secretion we discussing this in lecture the number one molecule that I want you thinking about that is secreted is H+ hydrogen ions okay and and the reason I want you thinking about this is that we are constantly making acids constantly making acids our our metabolism at as we break down molecules for energy our body is making acid and we have to get rid of that acid somehow so we&#39;ll see that uh the distal convoluted tubal&#39;s job is to do the process of secretion now that word is not what it seems to be secretion is the opposite of reabsorption we&#39;ll talk about this in a minute and you&#39;re going to see in lecture a little bit of a conversation about a couple hormones aldosterone and antidiuretic hormone ADH it&#39;s not a concern here for lab all I really want to talk about are the structures of the urinary system but in lecture you will hear me discuss aldosterone and ADH just a little bit and then that will be a major component of your learning in physiology so imagine that we have taken here a pyramid right so here&#39;s a pyramid taken out of this kidney we now see this pyramid shown here it&#39;s been very simplified we&#39;re only seeing a couple of nephrons um this nefron right here most of the tubing is up high this is a cortical nefron this one the tubing is a little bit lower and there is a very long and deep Loop of Henley so on this side this is a juxa medular nefron and on this side this is a cortical nefron just to see that again they do different jobs uh and when you get into the physiology of this you&#39;ll appreciate that more but I just want to point out there&#39;s two different types of nephrons so let&#39;s follow the the the the story here so blood would come into the aent material into the Glarus here it would be filtered that which does not get filtered out would leave out the eant right out the eant arterial what does go into the Glarus and gets filtered through would become part of the filtrate and that filtrate is going to start traveling through the proximal convoluted tubule as it passes through the convoluted tubal molecules are being re absorbed taken out of it useful molecules will be taken out of it it will then continue down the loop of Henley come back up into the distal convoluted tubal the job of the distal convoluted tubal is secretion talk about that again in a moment and then whatever has is left now in this fluid this filtrate we&#39;ll find its way and dump into a collecting duct notice that the collecting duck is receiving urine from many nephrons so this is a simplified picture many nephrons are dumping their urine into this collecting duct at the very end there is that renal Pilla again imagine a little drip spout here that is releasing the urine and then down here collecting this urine would be the minor Kix once the fluid gets into the collecting duct it&#39;s essentially urine there is a one last chance for the body to modify that fluid and in the collecting ducts if a person is well hydrated or if you&#39;re walking around and you&#39;re drinking and you&#39;re well hydrated um then everything that goes into the duct will simply make its way down to the bladder and be released however if you are dehydrated the body is going to try to conserve water and it will do its best to concentrate the urine even more and that hormone ADH will play a part in this concentrating of the urine again we&#39;ll deal with that more in lecture so now we&#39;ve talked very briefly about how the kidney is filtering the blood filtering out those waste products how those waste products make their way through the convoluted tubes through the nefron structure and then that concentrated fluid will be released to the bladder how does that work so as the urine is made which is being made 24/7 Around the Clock the bladder is going to be ready to receive that fluid it&#39;s an expandable muscular container um and in the female the blood is in contact with the uterus and in males it is in contact with the rectum as well as the prostate gland the bladder as well as the kidneys retrop peronal when the bladder is empty the bladder sort of looks like an upside down pyramid as it fills it assumes more of an oval shapee inside the bladder there&#39;s an area um called the trigone this is an area it&#39;s an imaginary area if you will but there are two openings for where the uers drop the fluid into the urine and then there&#39;s the opening for the urethra so you&#39;ll see sort of a three opening area triangle right trigone um and this you will see um in the in the bladder pictures in a moment basically the bladder acts as the funnel and as the bladder fills it starts to push on the sphincters that will give you then the urge to uh go to the go to the restroom the bladder has four tunics around it boy these look awfully familiar uh looks a lot like what we saw in the digestive structures the mucosa sub mucosa muscularis and the adventia so taking a look at this here are the urits coming down from the kidneys this is the peritoneum right we know the peritoneum that membrane that serus membrane that creates the abdominal pelvic uh cavity the bladder is below that inside the bladder there&#39;s rug sort of like what we see in the stomachs or a roughened area here we see two openings so this urine is is coming down and enters into the bladder here then here&#39;s the opening for the urethra so this is that triangular trigone area the wall of the bladder is a muscle the detrusor muscle we call to Truse means to force away we saw that in our vocabulary and as the bladder fills it begins to push here and right here there are smooth muscles uh the internal urethal sphincter as those get stretched it&#39;s going to give you the urge to go to the restroom and then further down there&#39;s the external urethal sphincter these are voluntary skeletal muscles over which you hopefully have control this is showing a female um bladder and right here is a layer of muscle we&#39;re going to see this in a moment but this is called the urogenital diaphragm uh when you think of the diaphragm you think of something that separates so this layer of muscle One Way think about sort of the pelvic floor is what separates the internal from the external structure we&#39;ll see it in the mail in a moment as well recall too that the inside of the bladder is lined by transitional epithelia so the urethra then is the way by which the urine leaves the bladder and it is surrounded by smooth muscle that will help Propel that urine out of the body two sphincters that I mentioned already the internal sphincter and the external sphincter the internal sphincter again is smooth muscle involuntary and then the external sphincter is voluntary basically this is your toilet training muscle right when you&#39;re training children how to hold themselves it&#39;s the external sphincter that the child is learning to control let&#39;s take a look again at this situation we&#39;ve got the urethal openings sorry the urer openings and then the urethal opening here internal sphincter smooth muscle here external sphincter here this muscle again on both sides would be considered the urogenital diaphragm and again this would be a female uthra in the male the urethra is both a passageway for urine and a passageway for semen it&#39;s a longer structure there are three parts to the male urethra prosthetic urethra the part that passes through the prostate itself a relatively short region called the membranous urethra this region is right there at that urogenital diaphragm layer and then the spongy urethra is passing through the spongy or erectile tissues of the penis the spongy urethra other books will call the penile urethra so looking at these structures so the bladder is the same so here are those openings for the ERS and here is the uthal opening but what we see in the mail now is the prostate gland so the prostate gland is shown here this Walnut shaped gland the urethra passes through the center of that prostate gland so in the blue area that&#39;s prosthetic urethra this yellowish green area is the membranous urethra so there is the urogenital diaphragm that muscular wall and then here in purple is the spongy or the p urethra passing through the erectile spongy regions of the penis next week we&#39;ll discuss the male reproductive system and we&#39;ll study more about those erectile tissues so what can go wrong with prostate if the prostate begins to enlarge which is a pretty typical aging phenomenon in men couple things happen one the prostate can start to squeeze down and make the Lumen make the passageway more restricted so what that does is it makes urination uh not be as complete uh the the the flow of urine is reduced okay the other thing that can happen though is as a prostate enlarges it can push up on the smooth muscle and that can give the guy the urge to go even though he doesn&#39;t have to go right so it&#39;s that pushing on that smooth muscle of the internal sphincter that gives one the urge to go so as the bladder uh the bladder may not be full but because of the enlarged prostate the guy is getting this constant feeling of having to go having to go and then they get there and there&#39;s nothing happening so those are some of the uh side effects of an enlarged prostate so today um in addition to looking over all of the structures of the kidney you&#39;re also going to be dissecting a kidney you&#39;ll find some lovely images in your lab Atlas but here is a uh kidney that&#39;s been opened up next to a lovely labeled kidney so it will be important that you can identify the cortex the medulla that you can recognize those pyramids within the medulla that you can recognize the minor and major koses the renal pelvis you should be able to find the urer coming off the kidney you should also on most specimens be able to see the renal artery and the renal vein you&#39;ll be able to see the renal columns in between the pyramids and you&#39;ll recognize that the outer container the outer layer of the kidney itself is that fibrous capsule

Transcript for:Prelab: Urinary System

Transcript for:
Prelab: Urinary System