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==Introduction==

|linkpage =Urinary System - Anatomy & Physiology

|linktext =URINARY SYSTEM

 

|maplink = Urinary System (Content Map) - Anatomy & Physiology

[[Image:sagkidlabelled.jpg|right|thumb|250px|<small><center>A labelled saggital section of a lamb kidney(Courtesy of Donal McNally - University of Nottingham)</center></small>]]

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==Common Anatomy==

==Common Anatomy==

[[Image:basicnormkidap.jpg|right|thumb|250px|<small><center>Histology section of a normal kidney (© RVC 2008)</center></small>]]

[[Image:basicnormkidap.jpg|right|thumb|250px|<small><center>Histology section of a normal kidney (© RVC 2008)</center></small>]]

[[Image:normkidcortap.jpg|right|thumb|250px|<small><center>Histology section of a normal renal cortex (© RVC 2008)</center></small>]]

[[Image:normkidcortap.jpg|right|thumb|250px|<small><center>Histology section of a normal renal cortex (© RVC 2008)</center></small>]]

[[Image:promaledogab.jpg|right|thumb|250px|<small><center>A prosection of the abdomen of a male dog (© UoN 2008)</center></small>]]

[[Image:promaledogab.jpg|right|thumb|250px|<small><center>A prosection of the abdomen of a male dog (© UoN 2008)</center></small>]]

[[Image:profemaledogab.jpg|right|thumb|250px|<small><center>A prosection of the abdomen of a female dog(© UoN 2008)</center></small>]]

[[Image:profemaledogab.jpg|right|thumb|250px|<small><center>A prosection of the abdomen of a female dog(© UoN 2008)</center></small>]]

* The kidney is the part of the urinary tract where blood is filtered and urine is produced.  

* The kidney is the part of the urinary tract where blood is filtered and urine is produced.  

* The kidneys are paired and lie in a retroperitoneal position.   

* The kidneys are paired and lie in a retroperitoneal position.   

* They are positioned in the caudo-dorsal abdomen.

* They are positioned in the caudo-dorsal abdomen.

* They lie within a splitting of the sublumbar fascia.  This also often contains a large quantity of fat to cushion and protect the kidneys from the pressure of other organs   

* They lie within a splitting of the sublumbar fascia.  This also often contains a large quantity of fat to cushion and protect the kidneys from the pressure of other organs   

* The right kidney is most cranial in all species except the pig.

* The right kidney is most cranial in all species except the pig and grasscutter.

* In species where the right kidney is most cranial it lies in a small fossa of the caudate liver lobe.

* In species where the right kidney is most cranial it lies in a small fossa of the caudate liver lobe.

* However the left kidney is the most mobile.

* However the left kidney is the most mobile.

* External zone

* External zone

* Internal zone (juxtamedullar)

* Internal zone (juxtamedullar)

* Contains the following parts of the [[The Nephron - Anatomy & Physiology| nephron]]

* Contains the following parts of the [[:Category:Nephron| nephron]]

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#The Renal Corpuscle| Renal corpuscle]]

** [[Nephron Microscopic Anatomy #The Renal Corpuscle| Renal corpuscle]]

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#Proximal Tubule| Proximal convoluted tubule]]

** [[Nephron Microscopic Anatomy #Proximal Tubule| Proximal convoluted tubule]]

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#The Distal Tubule| Distal convoluted tubule]]

** [[Nephron Microscopic Anatomy #The Distal Tubule| Distal convoluted tubule]]

** [[Useful definitions - Renal Anatomy & Physiology#M| Medullary Rays]]

** [[WikiWords#Urinary Section| Medullary Rays]]

===Renal Medulla===

===Renal Medulla===

* Contains medullary pyramids

* Contains medullary pyramids

* The part nearest the cortex is the base of the pyramid which narrows to form the inner part - renal papilla

* The part nearest the cortex is the base of the pyramid which narrows to form the inner part - renal papilla

* The medulla can be split into two parts, the outer and the inner

* The medulla can be split into two parts, the outer and the inner

* Different parts of the [[The Nephron - Anatomy & Physiology| nephron]] reside in these areas

* Different parts of the [[:Category:Nephron| nephron]] reside in these areas

* The outer medulla, which can be further divided into the outer and inner stripe, contains the following parts of the [[The Nephron - Anatomy & Physiology| nephron]]:

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#Proximal Tubule| Proximal straight tubules]]

The outer medulla can be further divided into the outer and inner stripe

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#The Distal Tubule| Distal straight tubule]]

 

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#The Loop of Henle| Loop of henle]]

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#Collecting Duct| Collecting ducts]]

This section located just inside the cortex contains the following parts of the [[:Category:Nephron| nephron]]:

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology #The Vasa Recta| Vasa recta]]

* [[Nephron Microscopic Anatomy #Proximal Tubule| Proximal straight tubules]]

* [[Nephron Microscopic Anatomy #The Distal Tubule| Distal straight tubules]]

* [[Nephron Microscopic Anatomy #The Loop of Henle| Thin descending and thick ascending limbs of the loop of henle]]

* [[Nephron Microscopic Anatomy #Collecting Duct| Outer medullary collecting ducts]]

* [[Nephron Microscopic Anatomy  #The Vasa Recta| Vasa recta]]

 

* [[Nephron Microscopic Anatomy #The Loop of Henle| Thin ascending and thick ascending limbs of the loop of henle]]

* [[Nephron Microscopic Anatomy #Collecting Duct| Outer medullary collecting ducts]]

 

 

 

* The inner medulla however only contains the following parts:

* The inner medulla however only contains the following parts:

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#The Loop of Henle| Loop of henle]]

** [[Nephron Microscopic Anatomy #The Loop of Henle| Loop of henle]]

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#Collecting Duct| Collecting ducts]]

** [[Nephron Microscopic Anatomy #Collecting Duct| Collecting ducts]]

** [[Microscopic Anatomy of the Nephron - Anatomy & Physiology #The Vasa Recta| Vasa recta]]

** [[Nephron Microscopic Anatomy #The Vasa Recta| Vasa recta]]

===Renal Pelvis===

===Renal Pelvis===

* All papillary ducts open here

* All papillary ducts open here

* The renal pelvis then drains into the ureters

* The renal pelvis then drains into the ureters

* Varies between species

* Varies between species

* Absent in cow

* Absent in cow

* Contains mucous glands in the horse

* Contains mucous glands in the horse

* The kidney is divided into [[Useful definitions - Renal Anatomy & Physiology | renal lobes]] from a structural point of view.

* These are then subdivided into [[The Nephron - Anatomy & Physiology| nephrons]], [[Useful definitions - Renal Anatomy & Physiology | a medullary ray]] and [[Microscopic Anatomy of the Nephron - Anatomy & Physiology#Collecting Duct| a collecting duct]] to form a [[Useful definitions - Renal Anatomy & Physiology | renal lobule]]

 

* The kidney is divided into [[WikiWords#Urinary Section| renal lobes]] from a structural point of view.

* These can then be divided into a renal pyramid and the piece of cortex above it

**These structures are visible grossly and are the region of the medulla which appears triangular in cross section. They are actually cone shaped and the pointed part which faces towards the renal pelvis is termed the apex and the part against the cortex the base.

* They can also be subdivided into [[WikiWords#Urinary Section| renal lobules]] comprising of [[:Category:Nephron| nephrons]], [[WikiWords#Urinary Section| a medullary ray]] and [[Nephron Microscopic Anatomy #Collecting Duct| a collecting duct]].

 

===Innervation===

===Innervation===

These species all have similar renal anatomy. Their kidneys are relatively short and thick and they are the traditional kidney bean shape. They have a smooth outer surface and have a single renal papilla.  The renal pelvis is large and irregular with recesses which are finger like processes.

These species all have similar renal anatomy. Their kidneys are relatively short and thick and they are the traditional kidney bean shape. They have a smooth outer surface and have a single renal papilla.  The renal pelvis is large and irregular with recesses which are finger like processes.

The kidney of the feline is relatively bigger than the other species and is quite distinctive because the sub-capsular veins which run towards the hilum are visible.

The kidney of the feline is relatively bigger than the other species and is quite distinctive because the sub-capsular veins which run towards the hilum are visible. The size of the kidney can be estimated by palpation or via imaging. On a ventrodorsal radiograph, normal kidney size is usually between two to three times the length of second lumbar vertebra, 3 - 4.5 centimetres.

===Bovine===

===Bovine===

The kidneys of the bovine do not lose their foetal lobulation.  In fact the surface of each kidney is divided into approximately 12 lobules.    The right kidney is flattened and ellipsoidal where as the left kidney is thicker at the caudal end than the cranial.  Each kidney is surrounded by the capsula adiposa; a layer of fat.  Despite what it’s externally lobulated appearance may suggest the cortex of the bovine kidney is continuous and the kidney is of multipyramidal type.  The bovine kidney has no renal pelvis but rather the [[Ureters - Anatomy & Physiology | Ureters]] enters the kidney and divide into a cranial and caudal branch.  These branches then subdivide and the papilla at the apex of the pyramids open and drain into these.

 

The kidneys of the bovine do not lose their foetal lobulation.  In fact the surface of each kidney is divided into approximately 12 lobules.    The right kidney is flattened and ellipsoidal where as the left kidney is thicker at the caudal end than the cranial.  Each kidney is surrounded by the capsula adiposa; a layer of fat.  Despite what it’s externally lobulated appearance may suggest, the cortex of the bovine kidney is continuous and the kidney is of multipyramidal type.  The bovine kidney has no renal pelvis but rather the [[Ureters - Anatomy & Physiology | Ureters]] enters the kidney and divide into a cranial and caudal branch.  These branches then subdivide and the papilla at the apex of the pyramids open and drain into these.

The right ureter leaves the kidney and passes along the roof of the abdomen to the pelvis in a fairly standard pattern.  The left ureter however moves across the dorsal surface of its kidney to return to the midline and follow a course as if the kidney was located on the left.  (both kidneys in the bovine are located on the right see the anatomical landmarks section for further details)

The right ureter leaves the kidney and passes along the roof of the abdomen to the pelvis in a fairly standard pattern.  The left ureter however moves across the dorsal surface of its kidney to return to the midline and follow a course as if the kidney was located on the left.  (both kidneys in the bovine are located on the right see the anatomical landmarks section for further details)

===Porcine===

===Porcine===

The kidneys are dorsoventrally flattened.  The renal pelvis opens into quite a large space of two major calicyes from which bud about 10 minor calyces.  These attach to one renal papillae each.  The kidneys have a smooth surface.

 

The kidneys are dorsoventrally flattened.  The renal pelvis opens into quite a large space of two major calyces from which bud about 10 minor calyces.  These attach to one renal papilla each.  The kidneys have a smooth surface.

===Equine===

===Equine===

Medially to the right kidney you will find the caudal vena cava and the right adrenal gland can be found dorsolateral to this structure but still medially to the kidney.  Ventrally can be found the Descending [[Duodenum - Anatomy & Physiology|duodenum]] with the right pancreatic limb more towards the ventromedial aspect.  In females the right ovary can be found caudoventrally.

Medially to the right kidney you will find the caudal vena cava and the right adrenal gland can be found dorsolateral to this structure but still medially to the kidney.  Ventrally can be found the Descending [[Duodenum - Anatomy & Physiology|duodenum]] with the right pancreatic limb more towards the ventromedial aspect.  In females the right ovary can be found caudoventrally.

The '''Cranial pole''' of the left kidney contacts the [[Stomach and Abomasum - Anatomy & Physiology | Greater curvature of stomach]] it also contacts the [[Spleen - Anatomy & Physiology|spleen]] on its dorsomedial aspect as well as potentially contacting the left limb of the pancreas.  The left adrenal gland can be found at the medial aspect of the cranial pole.  The '''Caudal pole''' of the left kidney contacts the [[Small Intestine - Anatomy & Physiology|Small intestine]] and the Descending [[Colon - Anatomy & Physiology|colon]].  At its caudoventral aspect in females is found the left Ovary.

The '''Cranial pole''' of the left kidney contacts the [[Monogastric Stomach - Anatomy & Physiology|greater curvature of stomach]] it also contacts the [[Spleen - Anatomy & Physiology|spleen]] on its dorsomedial aspect as well as potentially contacting the left limb of the pancreas.  The left adrenal gland can be found at the medial aspect of the cranial pole.  The '''Caudal pole''' of the left kidney contacts the [[Small Intestine Overview - Anatomy & Physiology|Small intestine]] and the Descending [[Colon - Anatomy & Physiology|colon]].  At its caudoventral aspect in females is found the left Ovary.

===Ruminants===

===Ruminants===

===Internal Vascularisation===

===Internal Vascularisation===

Once the renal artery enters the kidney is divides into the interlobar arteries.  These pass through the gaps between the renal pyramids as the reach the junctions between the cortex and medullar they branch into the arcuate arteries which move over the base of the pyramids.  From these come the interlobular arteries which supply the individual lobules of the cortex.  These arteries then branch many times to supply individual glomeruli.  The capillaries of the glomerulus then rejoin to form one vessel which then forms the [[Peritubular Capillaries - Anatomy & Physiology|peritubular capillaries]] of that nephron.  The interlobular arteries are examples of end arterioles and there are few anastomoses.  Obstruction of one of these arterioles causes ischaemic damage in the kidneys.  This is also potentially the case with the interlobar arteries.

Once the renal artery enters the kidney is divides into the interlobar arteries.  These pass through the gaps between the renal pyramids as the reach the junctions between the cortex and medullar they branch into the arcuate arteries which move over the base of the pyramids.  From these come the interlobular arteries which supply the individual lobules of the cortex.  These arteries then branch many times to supply individual glomeruli.  The capillaries of the glomerulus then rejoin to form one vessel which then forms the [[Glomerular Apparatus and Filtration - Anatomy & Physiology#Pressure in the Peritubular Capillaries|peritubular capillaries]] of that nephron.  The interlobular arteries are examples of end arterioles and there are few anastomoses.  Obstruction of one of these arterioles causes ischaemic damage in the kidneys.  This is also potentially the case with the interlobar arteries.

==The Endocrine Function of The Kidney==

 

|dragster =[[Comparative Kidney Anatomy Dragster resource]]

The endocrine function of the kidneys comprises the production and release of two hormones - [[Erythropoiesis - WikiBlood#Regulation|Erythropoietin]] and [[Juxtaglomerular Cells of The Distal Tubule - Renal Physiology #Renin| Renin]] both from the [[Juxtaglomerular Cells of The Distal Tubule - Renal Physiology |juxtaglomerular complexes]].  It is also responsible for the regulation of the [[Calcium Homeostasis - Anatomy & Physiology #Active Vitamin D Synthesis |activation of vitamin D]]

|flashcards = [[Macroscopic Renal Anatomy - Renal Flash Cards - Anatomy & Physiology]]

|videos = [[Video: Feline Abdomen|Feline Abdomen potcast]]<br>[[Video: Bovine Pregnant Uterus|Bovine pregnant uterus potcast]]<br>[[Video: Bovine liver potcast 2|Bovine liver potcast 2]]<br>[[Video: Feline abdominal and pelvic cavity potcast|Feline abdominal and pelvic cavity potcast]]<br>[[Video: Bovine pregnant uterus potcast 2|Bovine pregnant uterus potcast 2]]<br>[[Video: Lateral view of the pelvic cavity and reproductive tract of the cow potcast|Lateral view of the pelvic cavity and reproductive tract of the cow potcast]]

==Renal Pathology==

==Webinars==

The pathology of the kidney is beyond the scope of this section but can be found [[Urinary System - Pathology| here]]

[[Category:Kidney - Anatomy & Physiology]][[Category:Bullet Points]]