Hello to all anatomy enthusiasts. Hello to all anatomy enthusiasts. Welcome to a new video of Easy Anatomy by Juan Jose Sanchez.
Welcome to a new video of Easy Anatomy by Juan Jose Sanchez. Today I bring you the second and final installment of the anatomy of the kidney. Today I bring you the second and final installment of the anatomy of the kidney.
Before this one, Before this one, I uploaded a video talking about the first part of the kidney where we covered generalities, I uploaded a video talking about the first part of the kidney where we covered generalities, the renal capsule, the renal capsule, the envelopes and the most important relationships of the kidney. the envelopes and the most important relationships of the kidney. With this one, With this one, We would finish covering the last topics of the kidney and I invite you to watch the video on the renal artery and vein so that you finally understand how the kidney is irrigated and in what arrangement the renal artery is placed and how it is venously drained by the renal vein.
We would finish covering the last topics of the kidney and I invite you to watch the video on the renal artery and vein so that you finally understand how the kidney is irrigated and in what arrangement the renal artery is placed and how it is venously drained by the renal vein. Let's start without further ado by first talking to you about the internal structure of the kidney. Let's start without further ado by first talking to you about the internal structure of the kidney. Many people have asked me for a video on the renal ultrastructure, Many people have asked me for a video on the renal ultrastructure, to talk about the genital, to talk about the genital, the straight tubules, the straight tubules, convoluted tubules, convoluted tubules, but really that is more histological than anatomical.
but really that is more histological than anatomical. That's why here we're going to cover the things we see in general terms when we do a simple dissection of a kidney without going into the ultra structure, That's why here we're going to cover the things we see in general terms when we do a simple dissection of a kidney without going into the ultra structure, which as I said, which as I said, would be histology. would be histology. I don't rule out making that video at some point, I don't rule out making that video at some point, but I don't have it planned at the moment. but I don't have it planned at the moment.
Speaking of the internal structure of the kidney, Speaking of the internal structure of the kidney, in the last video we left off with the outermost part of the kidney, in the last video we left off with the outermost part of the kidney, which was the renal capsule. which was the renal capsule. This renal capsule was part of the outermost covering of the kidney and I told you that it was very easy to separate it from the kidney itself when the kidney was healthy, This renal capsule was part of the outermost covering of the kidney and I told you that it was very easy to separate it from the kidney itself when the kidney was healthy, but that in a diseased kidney it was quite complicated because this renal capsule practically adhered to it. but that in a diseased kidney it was quite complicated because this renal capsule practically adhered to it. So, So, in this image that I'm showing you, in this image that I'm showing you, you see a section of a kidney, you see a section of a kidney, we're seeing it from the front.
we're seeing it from the front. This part that is already in the internal structure of the kidney, This part that is already in the internal structure of the kidney, which would be practically below the capsule, which would be practically below the capsule, is what we call the cortex of the kidney. is what we call the cortex of the kidney.
The kidney is basically made up of two large structures, The kidney is basically made up of two large structures, a cortex and an internal structure, a cortex and an internal structure, which are these triangles and once I get ahead of myself, which are these triangles and once I get ahead of myself, which are what we call the medulla. which are what we call the medulla. So this cortex, So this cortex, apart from being, apart from being, let's say, let's say, like the outermost covering of the kidney, like the outermost covering of the kidney, is also found separating the medullary structures, is also found separating the medullary structures, as we are going to see right now.
as we are going to see right now. Note that the parts of the renal cortex, Note that the parts of the renal cortex, the cortical parts that are placed between the medulla are what we call the renal septum. the cortical parts that are placed between the medulla are what we call the renal septum. Before, Before, when hyponyms were accepted in anatomy, when hyponyms were accepted in anatomy, they were called septa of vertin or septa of bertini. they were called septa of vertin or septa of bertini.
Today we simply do not call it the renal septum. Today we simply do not call it the renal septum. So, So, that is basically the cortex. that is basically the cortex.
When we study the arterial part in the kidney arteries, When we study the arterial part in the kidney arteries, You will see that there are some arteries that penetrate the renal cortex, You will see that there are some arteries that penetrate the renal cortex, as you can see there, as you can see there, but well, but well, that is not part of this video. that is not part of this video. Studying the medulla, Studying the medulla, which is a little more complex, which is a little more complex, despite being shorter in length, despite being shorter in length, it is more complex in anatomy, it is more complex in anatomy, we are going to start by talking about these medullary structures that are inverted pyramids and in fact are called renal pyramids.
we are going to start by talking about these medullary structures that are inverted pyramids and in fact are called renal pyramids. These renal pyramids have an external base that is practically in contact with the cortex and a lower vertex that goes towards the internal part, These renal pyramids have an external base that is practically in contact with the cortex and a lower vertex that goes towards the internal part, towards the central part of the kidney. towards the central part of the kidney. Approximately 10 to 12 pyramids are found in each kidney, Approximately 10 to 12 pyramids are found in each kidney, although some kidneys can even have more than 15 pyramids, although some kidneys can even have more than 15 pyramids, but the most common is that there are 10 to 12 renal pyramids. but the most common is that there are 10 to 12 renal pyramids.
Previously, Previously, we knew these renal pyramids by the name of Malpili pyramids. we knew these renal pyramids by the name of Malpili pyramids. with ghg at the end.
with ghg at the end. Today, Today, by removing that name, by removing that name, we simply call them renal pyramids. we simply call them renal pyramids. Notice that the tip of the pyramids becomes a little pale and that tip is leading to these structures that are now the urine collecting system.
Notice that the tip of the pyramids becomes a little pale and that tip is leading to these structures that are now the urine collecting system. These are the famous minor calyxes that we are going to study. These are the famous minor calyxes that we are going to study. Right now, Right now, what I want you to know is that the mula is embedded, what I want you to know is that the mula is embedded, that is, that is, it basically fits into these minor calyxes through the papilla. it basically fits into these minor calyxes through the papilla.
So, So, that pale area is the papilla. that pale area is the papilla. And what specifically is in that papilla?
And what specifically is in that papilla? Well, Well, in that papilla is where the final duct of the nephron, in that papilla is where the final duct of the nephron, which in this case would be the renal collecting tubule, which in this case would be the renal collecting tubule, is the one that finally carries the drop of urine, is the one that finally carries the drop of urine, or the urine, or the urine, and takes it to the minor calyxes. and takes it to the minor calyxes.
And they, And they, then, then, will take it to the major ones, will take it to the major ones, and the major ones to the renal pelvis, and the major ones to the renal pelvis, and that is where the urine begins to be poured, and that is where the urine begins to be poured, or excreted. or excreted. Anyway, Anyway, Let's see this image a little bigger. Let's see this image a little bigger.
Look at how these are, Look at how these are. This is a nephron. this is a nephron, this is one, This is one.
this is what I was telling you about the ultra structure of the kidney, This is what I was telling you about the ultra structure of the kidney. but in the end it will reach the collecting tubule and all the way to the But in the end it will reach the collecting tubule and all these collecting tubules perforate the renal papilla, All these collecting tubules perforate the renal papilla, which is this. which is this. This is like the tip of the medulla, This is like the tip of the medulla, so you can imagine. so you can imagine.
And see that each collecting tubule or many collecting tubules perforate each papilla. And see that each collecting tubule or many collecting tubules perforate each papilla. In fact, In fact, it is said that there may be approximately 500 collecting tubules for each kidney.
it is said that there may be approximately 500 collecting tubules for each kidney. So this area of the papilla, So this area of the papilla, which is the one that is inside the minor calyx, which is the one that is inside the minor calyx, has many small holes. has many small holes.
It looks like a colander. It looks like a colander. That is why anatomists gave it the name of the cribriform area of the papilla or cribriform area. That is why anatomists gave it the name of the cribriform area of the papilla or cribriform area.
Because cribriform means shape like a colander. Because cribriform means shape like a colander. See, See, it is the shape of a colander itself. it is the shape of a colander itself.
Very well, Very well, now you know that these are the tubes and collectors and this would be the cribriform or cribriform area of the kidney. now you know that these are the tubes and collectors and this would be the cribriform or cribriform area of the kidney. Let's talk quickly now about the lobes of the kidney. Let's talk quickly now about the lobes of the kidney.
Perhaps you are not familiar with this term. Perhaps you are not familiar with this term. But it turns out that embryologically the kidney is formed by the union of many lobes. But it turns out that embryologically the kidney is formed by the union of many lobes. In fact, In fact, these lobes are approximately between 11 and 17 lobes.
these lobes are approximately between 11 and 17 lobes. Each lobe can have up to 17 to 19 lobes. Each lobe can have up to 17 to 19 lobes. Each lobe is made up of a Malpighi pyramid with the cortex that surrounds them.
Each lobe is made up of a Malpighi pyramid with the cortex that surrounds them. So, So, if you see that there are 10 to 12 pyramids for each kidney, if you see that there are 10 to 12 pyramids for each kidney, then more or less those are the set of lobes that probably formed that kidney. then more or less those are the set of lobes that probably formed that kidney. This is a child's kidney. This is a child's kidney.
This is so that you more or less understand the concept of ovulation. This is so that you more or less understand the concept of ovulation. Those lobes begin to join together until, Those lobes begin to join together until, in the adult stage, in the adult stage, there is practically no lobulated kidney as such. there is practically no lobulated kidney as such.
Instead, Instead, we can see traces that perhaps there were or were lobes that joined, we can see traces that perhaps there were or were lobes that joined, but it is a single structure in the adult. but it is a single structure in the adult. Let's continue talking about the kidneys. Let's continue talking about the kidneys.
We are going to talk about the pedicle area and the renal sinus area. We are going to talk about the pedicle area and the renal sinus area. But before that, But before that, don't leave this video.
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we still have a lot to do. If there is an anatomy video that you don't see here, If there is an anatomy video that you don't see here, but that you want to ask me for, but that you want to ask me for, you can comment below in this video. you can comment below in this video. I will surely read it and at some point I will make the video that you are requesting. I will surely read it and at some point I will make the video that you are requesting.
It's just that sometimes I don't have time to respond to everyone's comments or make the videos that everyone requests, It's just that sometimes I don't have time to respond to everyone's comments or make the videos that everyone requests, but I always take them into account. but I always take them into account. Speaking of the renal peduncle, Speaking of the renal peduncle, remember that in the previous video we talked about the hilum and the hilum was the area on the inner surface of the kidney or the inner edge where the structures enter or exit the kidney.
remember that in the previous video we talked about the hilum and the hilum was the area on the inner surface of the kidney or the inner edge where the structures enter or exit the kidney. So, So, those structures that enter and exit the kidney are what we call the renal pedicle. those structures that enter and exit the kidney are what we call the renal pedicle.
Basically, Basically, Lymphatics and nerves enter the kidney, Lymphatics and nerves enter the kidney, but these are structures that very few of us study. but these are structures that very few of us study. When we talk about the renal pelvic tract, When we talk about the renal pelvic tract, we almost always study a classic triad of three things. we almost always study a classic triad of three things. We are talking about a renal vein, We are talking about a renal vein, which is the most anterior structure that penetrates at the level of the pedicle.
which is the most anterior structure that penetrates at the level of the pedicle. Behind it we find the renal pelvis, Behind it we find the renal pelvis, which you may not be familiar with, which you may not be familiar with, but you will learn about it now. but you will learn about it now. It is better known as the pelvis of the ureter.
It is better known as the pelvis of the ureter. It is very incorrectly called the renal pelvis. It is very incorrectly called the renal pelvis. But that is what the anatomical list calls it. But that is what the anatomical list calls it.
Otherwise, Otherwise, it is ideally called the pelvis of the ureter. it is ideally called the pelvis of the ureter. This is posterior to the renal vein.
This is posterior to the renal vein. And the renal artery has a disposition that, And the renal artery has a disposition that, apart from being variable, apart from being variable, its terminal branches are intertwined with the renal vein and with the renal pelvis. its terminal branches are intertwined with the renal vein and with the renal pelvis.
That is the specific disposition of this renal pedicle. That is the specific disposition of this renal pedicle. If we look at it in this image, If we look at it in this image, we see the anterior renal vein again. we see the anterior renal vein again.
Remember that there is a video dedicated solely to the renal vein. Remember that there is a video dedicated solely to the renal vein. Behind it is the renal pelvis or pelvis of the ureter. Behind it is the renal pelvis or pelvis of the ureter.
And look at the even more posterior arrangement of the renal artery and its terminal branches that are penetrating at the level of the renal hilum. And look at the even more posterior arrangement of the renal artery and its terminal branches that are penetrating at the level of the renal hilum. Now speaking of the renal sinus, Now speaking of the renal sinus, remember that the entrance to, remember that the entrance to, let's say, let's say, the kidney, the kidney, to the internal part of the kidney was the hilum that was located on its internal or medial edge. to the internal part of the kidney was the hilum that was located on its internal or medial edge. Well, Well, That takes me to a space, That takes me to a space, a hollow literally, a hollow literally, which is a recess that is really the renal sinus.
which is a recess that is really the renal sinus. In that renal sinus we are going to see that it is also lined, In that renal sinus we are going to see that it is also lined, you see, you see, by the same renal capsule. by the same renal capsule.
It is lined by the renal capsule. It is lined by the renal capsule. At the level of that renal sinus is where we find the famous.
At the level of that renal sinus is where we find the famous. Look here in this section, Look here in this scene. section. before explaining that, Before explaining that, in this cross section, in this cross section, all this space that is there is the renal sinus. all this space that is there is the renal sinus.
And notice how the entire sinus is also lined by that renal capsule as such. And notice how the entire sinus is also lined by that renal capsule as such. There we also find a sedimentary tissue that is part of the pararenal tissue or paranefric tissue. There we also find a sedimentary tissue that is part of the pararenal tissue or paranefric tissue.
Very well, Very well, that is where we find the famous renal pelvis or pelvis of the ureter. that is where we find the famous renal pelvis or pelvis of the ureter. I'm going to explain the ureter to you in another video that we're going to watch. I'm going to explain the ureter to you in another video that we're going to watch.
So I'm going to explain how this ureter was previously the renal pelvis, So I'm going to explain how this ureter was previously the renal pelvis, how this renal pelvis was the major calyxes, how this renal pelvis was the major calyxes, and how the major calyxes were the minor calyxes. and how the major calyxes were the minor calyxes. I'm going to start from distal to proximal.
I'm going to start from distal to proximal. This renal pelvis is shaped like a vessel, This renal pelvis is shaped like a vessel, in fact, in fact, that's what they call it, that's what they call it, a funnel shape. a funnel shape. All the urine produced by the kidneys is captured by the renal pelvis and carried through the ureters to the bladder. All the urine produced by the kidneys is captured by the renal pelvis and carried through the ureters to the bladder.
So, So, This renal pelvis in its highest portion will measure 2-3 cm or 20-30 mm, this renal pelvis in its highest portion will measure 2-3 cm or 20-30 mm, as the LeTarget test says. as the LaTarget test says. And in its widest part it measures 1.5-2 cm.
And in its widest part it measures 1.5-2 cm. We're going to divide it into two portions. We're going to divide it into two portions.
One portion that remains inside the renal sinus, One portion that remains inside the renal sinus, which would be the portion that is in green here, which would be the portion that is in green here, which is the intrarenal portion, which is the intrarenal portion, and a portion that remains outside, and a portion that remains outside, the renal sinus, the renal sinus, which is what we see, which is what we see, which would be the extrarenal portion. which would be the extrarenal portion. Very good.
Very good. Aside from those portions, Aside from those portions, we're going to see a base whose base faces into the renal sinus. we're going to see a base whose base faces into the renal sinus. The base is where the major calyx is empty.
The base is where the major calyx is empty. Then it narrows in an area called the neck until it finally reaches the vertex, Then it narrows in an area called the neck until it finally reaches the vertex, which is the final part of the renal pelvis when it becomes the ureter. which is the final part of the renal pelvis when it becomes the ureter.
I was trying to find the anatomical point where I stopped calling it the renal pelvis and started calling it the ureter, I was trying to find the anatomical point where I stopped calling it the renal pelvis and started calling it the ureter, and I really couldn't find it. and I really couldn't find it. I couldn't find it in the books or online.
I couldn't find it in the books or online. If any of you know where I theoretically stop calling it the renal pelvis and start calling it the ureter, If any of you know where I theoretically stop calling it the renal pelvis and start calling it the ureter, let me know in this video so that I can learn it too. let me know in this video so that I can learn it too.
These are the structures that make up or into which the renal pelvis is divided. These are the structures that make up or into which the renal pelvis is divided. It also consists of two surfaces, It also consists of two surfaces, an anterior surface that we're seeing here and one that's exactly the same as this one, an anterior surface that we're seeing here and one that's exactly the same as this one, but that's behind the posterior surface.
but that's behind the posterior surface. It is said that it is actually flattened when there is no urine at this level of the renal pelvis, It is said that it is actually flattened when there is no urine at this level of the renal pelvis, but it bulges, but it bulges, it literally bulges when the production of urine that passes through the renal pelvis increases. it literally bulges when the production of urine that passes through the renal pelvis increases.
Then we would have two edges, Then we would have two edges, an upper edge, an upper edge, C, C, which is rather convex upwards and a lower edge that is concave downwards and that is much shorter than the upper edge. which is rather convex upwards and a lower edge that is concave downwards and that is much shorter than the upper edge. Speaking then of the major calyxes, Speaking then of the major calyxes, these major calyxes are 2 to 3. these major calyxes are 2 to 3. Remember that calyx means that it has the shape of a cup.
Remember that calyx means that it has the shape of a cup. So, So, these three major calyxes are going to be the ones that bring the urine from the minor calyxes and take it to the urethral pelvis. these three major calyxes are going to be the ones that bring the urine from the minor calyxes and take it to the urethral pelvis.
So, So, it would be formed by an upper major calyx, it would be formed by an upper major calyx, which is this one that we are seeing here, which is this one that we are seeing here, which is oblique downwards, which is oblique downwards, a middle major calyx. a middle major calyx. This would be the upper major calyx. This would be the upper major calyx. This is the middle major calyx, This is the middle major calyx, which is said to be horizontal and that generally drains two or a maximum of three minor calyxes from the middle portion of the kidney.
which is said to be horizontal and that generally drains two or a maximum of three minor calyxes from the middle portion of the kidney. The upper major calyx drains four to five minor calyxes from the upper portion of the kidney. The upper major calyx drains four to five minor calyxes from the upper portion of the kidney. Finally, Finally, the lower major calyx is oblique upwards and also drains three to four minor calyxes from the lower portion of the kidney. the lower major calyx is oblique upwards and also drains three to four minor calyxes from the lower portion of the kidney.
So, So, these are the famous major calyxes. these are the famous major calyxes. In order for these major calyxes to form, In order for these major calyxes to form, the minor calyxes had to join first.
the minor calyxes had to join first. Remember that we came from proximal, Remember that we came from proximal, from distal to proximal. from distal to proximal. So, So, there will be approximately 7 to 14 minor calyxes for each kidney.
there will be approximately 7 to 14 minor calyxes for each kidney. They have an upper end that is the part of the calyx, They have an upper end that is the part of the calyx, that is, that is, of the cup that fits over the renal pyramid where this famous structure that I explained to you at the end of the last slide is embedded, of the cup that fits over the renal pyramid where this famous structure that I explained to you at the end of the last slide is embedded, which was, which was, do you remember that I said it was somewhat whitish? do you remember that I said it was somewhat whitish?
Very good. Very good. So, So, those corrective tubules that penetrate or exit this structure, those corrective tubules that penetrate or exit this structure, which was the apex of this Malpighi pyramid, which was the apex of this Malpighi pyramid, end at the level of that minor calyx, end at the level of that minor calyx, specifically the upper extremity. specifically the upper extremity. Then the upper extremity is the one that will join the rest of the lower extremities and is the one that will end for the subsequent formation of the major calyxes.
Then the upper extremity is the one that will join the rest of the lower extremities and is the one that will end for the subsequent formation of the major calyxes. This structure here whose name I had forgotten specifically the renal papilla, This structure here whose name I had forgotten specifically the renal papilla, which fits on the upper extremity of those minor calyxes. which fits on the upper extremity of those minor calyxes.
That was the entire video for the second installment of the kidney. That was the entire video for the second installment of the kidney. I remind you to go watch the video on the renal artery and vein.
I remind you to go watch the video on the renal artery and vein. Don't forget to subscribe to the video, Don't forget to subscribe to the video, give it a like if you liked it and you can follow me on my social networks such as Instagram at ajanuisosacuteinches1315. give it a like if you liked it, and you can follow me on my social networks such as Instagram at agenuisosacuteenches1315. See you in the next videos. See you in the next videos.
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