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Dobrynya Shiryaev
Dobrynya Shiryaev

Arcuate Vein Of The Kidney

The urinary system is responsible for removing toxins, metabolic wastes and excess ions from the blood stream byway of urine. The primary organs producing urine are the kidneys. About 200 liters of fluid is filtered by the kidneys on a daily basis. These two bean shaped organs are positioned posterior to the peritoneal cavity, anterior to the dorsal wall and at about the height of the 12th ribs and spans between the T12 and L3 vertebrae. In summary the kidneys regulate the total volume of water in the body and the totalconcentration of solutes in that water (osmolality). They regulate the various ion concentrations in the extracellular fluids. They help maintain long-term acid-base balance. They remove foreign substances such as drugsand toxins. They produce renin and erythropoietin, which regulate blood pressure and red blood production, respectively.They help produce sugars via gluconeogenesis and convert vitamin D into its active form. While the kidneys form the urine, they are not, however, responsible for removing the urine from the body. The urinary systemhas three other important components namely: ureters, which are responsible for draining the urine fromthe kidneys into the urinary bladder, which temporarily stores the urine produced in the kidneys. Lastly,the urine is drained from the urinary bladder and voided from the body by way of the urethra, the last majorcomponent of the urinary system.

arcuate vein of the kidney

As mentioned in the introduction, the kidneys are bean shaped organs used to filter the body's blood supply.It is positioned posterior to the peritoneal cavity, anterior to the dorsal wall and at about the height of the 12th ribs and spans between the T12 and L3 vertebrae. A frontal section of the kidneys will reveal the following important components:

The image on the right is that of a nephron. To view enlarged image in a new window, simply click on image. (image by Orin James).Millions of nephrons can be found in the kidney. These are the functional units of the kidneys that produce urine. Majority of the components that comprisethe nephron can be found in the renal cortex. These include the renal corpuscle, proximal and distal convoluted tubules and parts of the nephron loop and collecting duct. The nephron loop and collecting duct continue into the renal medulla. It is important to note that although the major components of the nephronare found in the cortex, some nephrons may have these closer to the cortex-medulla junction than to the cortex. In the case where the major components are closer to the cortex-medulla junction, these will be called juxtamedullary nephrons. These tend to have a longer nephron loop/Loop of Henle and its efferent artery willfeed into the vasa recta. In the case where the major components of the nephron may be found further from the cortex-medulla junction, these will be calledcortical nephrons. They tend to have a shorter nephron loop/Loop of Henle than the juxtamedullary nephron. Their efferent arteries feed into peritubularcapillaries rather than the vasa recta capillaries. See The Renal Corpuscle here.

  • The image on the right is a photomicrograph of the tissue found in the renal cortex of the kidney (200x). It shows the renal corpuscle, proximal and distal convoluted tubles of the nephron. To view enlarged image in a new window, simply click on image. (image by Orin James).Distal Convoluted Tubules

  • Glomerulus

  • Parietal Layer of Glomerular/Bowman's Capsule:

  • Glomerular/Bowman's Capsule Space

-O. James

The ureters are responsible for conveying urine from the kidneys to the bladder. The bladder has three layers of tissue: Mucosa, which is composed of a transitional epitheliumand lamina propia. The second layer is Muscularis, which is composed of internal longitudaland external circular smooth muscle layers. This layer allows urine to be actively transported tothe bladder via muscular contractions. The third layer is Adventitia, which is the outermostcovering of the ureter.

Urine produced in kidneys are then drained, of ureters (1), into the bladder, which is a smooth, collapsible, muscular sac that temporarily stores urine ( 2, 3, 4,5, & 6). The bladder can collect up to about 200ml, before stretch receptors are activated. At this point impulses caused by contractions are sent to the parasympathetic division of the nervous system. As contractions continue urine may be forced past the internal sphincter (7) into superior part of the urethra. At this point the individual may feel the need to void. The individual may, however, not find it convenient to void at that point and inhibit the opening of this sphincter. If voiding is inhibited, bladder contractions may cease temporarily and the bladder may store another 200 to 300 ml of urine. After thisamount has been collected, the micturition reflex will be once again initiated. Once voiding has been initiated, urine will leave the body via the urethra. The length of the urethra differs between males and females. In males the urethra also runs the length of the penis and may reach a length of about 8 inches, while in females the urethra lies anterior to the vaginal opening and posterior to the clitoris, extending only about 1.5 inches long.

Renal cell carcinoma, especially the clear cell type, often gains access to large tumor-draining veins while the primary tumor is still intrarenal.1, 2 This propensity for intravenous growth can be extensive, initially involving sinus veins, proceeding to the main renal vein, continuing into the vena cava, and on occasion, reaching the right ventricle.3, 4, 5 This impressive tendency for intravenous growth can also involve the renal venous system in regions of the kidney distant from the primary tumor. When this occurs it may not always be recognized as an intravenous process. One author (SB) first recognized this phenomenon several years ago. It is briefly mentioned in two recent publications but has not been reported in detail.6, 7 This study investigates the incidence and defines the gross and histological features of retrograde venous invasion.

Main renal vein invasion was defined as tumor in an enlarged vein visible at the renal hilum before opening the specimen. Retrograde venous invasion was defined as rounded or elongated nodules of tumor separated from the primary tumor by uninvolved renal parenchyma. Tumor nodules must be in a location that conforms to the normal venous outflow of the kidney, that is, between renal pyramids or at the cortical-medullary junction.

Two blocks of tissue from each case of retrograde venous invasion were stained with a short panel of histochemical and immunohistochemical stains in an attempt to demonstrate the intravascular nature of the tumor nodules. These stains included elastic van Gieson stain, Masson trichrome stain, desmin and CD31. Stained sections were reviewed for evidence of vein wall and endothelial cell lining.

In all cases with retrograde venous invasion the unopened nephrectomy specimen had grossly obvious main renal vein involvement. By opening the specimens through the venous system, contiguous venous involvement from the main renal vein to the primary tumor was evident (Figures 1 and 2). In addition, contiguous venous involvement from the main renal vein to sinus veins, and proximal, to veins exiting the cortex from non-tumorous areas was readily visible in 7/9 cases (Figures 1 and 2). In two cases additional parallel sections were required to clearly demonstrate the process (Figure 3).

This clear-cell carcinoma invaded the inferior vena cava, the main renal vein (M) and sinus veins (large arrow). Nodules of retrograde venous invasion tumor are also present within the renal parenchyma (small arrow). P, primary tumor.

(a) This clear-cell carcinoma shows a partially necrotic primary tumor (P) and confluent sinus invasion (S). Adjacent to the primary tumor, tumor invades intralobar veins and multiple arcuate veins (arrows). (b) There are thick cylinders of tumor between the renal pyramids and arcades of tumor arrayed along the corticomedullary junction (arrows). All tumor nodules represent intravascular tumor.

This clear-cell renal cell carcinoma showed extensive sinus vein invasion on the initial section. This additional parallel section shows obvious retrograde venous invasion (arrows) with arcade of nodules draped around renal pyramids. Notice that the primary tumor is largely necrotic while the intravenous tumor appears viable. P, primary tumor.

(a) This arcuate vein contains tumor. It was located in a pole opposite the primary tumor. Grossly, it could be mistaken for a second primary tumor. P, renal pyramid. (b) This section from the tumor in panel a confirms that it is an arcuate vein located at the corticomedullary junction.

Microscopically, retrograde venous invasion was recognized by the combination of location, relationships and evidence of pre-existing vein. Location refers to the presence of tumor nodules between renal pyramids or bracketed by renal medulla and cortex, the normal location of intralobar and arcuate veins (Figures 4b, 6 and 7). Tumor extending from arcuate veins into one or more interlobular vein tributaries, was frequently identified (Figure 8). Relationship refers to the frequent presence of an artery adjacent to rounded tumor nodules, pertinent because renal arteries travel parallel to renal veins (Figures 6 and 7). When tumor nodules were small involving arcuate and intralobular veins, there was often a zone of separation between tumor and the vein wall, an obvious endothelial cell lining visible (Figures 4b, 8 and 9).

Identification of a pre-existing vein structure was impossible when an endothelial-lined zone of separation between tumor and vein wall was absent, as renal parenchymal veins lack appreciable smooth muscle media or elastica.1 This was affirmed with Masson trichrome and elastic stains and with staining for desmin. When retrograde venous invasion involved intralobar veins between the renal pyramids, a short interrupted segment of apparent vein wall smooth muscle media could be demonstrated by trichrome and desmin stains in some cases. However, when tumor involved arcuate veins and cortical interlobular veins, no vein wall smooth muscle media was ever apparent (Figure 10). Similarly, elastic stains failed to highlight a venous structure in any sized vein (Figure 11). 041b061a72


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