Changes

==Introduction==

==Introduction==

The kidneys are paired organs which reside in the dorsal abdomen.  One on the left and one on the right.  Their role is to filter the blood through the glomerulus to form what is known as the filtrate.  This filtrate is then on the whole reabsorbed along the nephron until what is left comprises compounds superfluous to the requirements of the organism.  Some compounds, normally fully reabsorbed, are on occasion present in the body in excess.  The kidney tubules are able to respond to this excess and excrete such compounds in greater amounts.  This is how the kidneys play a major role in the homeostasis of the organism.  The kidneys also plays a vital role in the total water balance of the organism.  Varying their excretion of water in relation to the hydration status of the animal.

The kidneys are paired organs which reside in the dorsal abdomen.  One on the left and one on the right.  Their role is to filter the blood through the glomerulus to form what is known as the filtrate.  This filtrate is then on the whole reabsorbed along the nephron until what is left comprises compounds superfluous to the requirements of the organism.  Some compounds, normally fully reabsorbed, are on occasion present in the body in excess.  The kidney tubules are able to respond to this excess and excrete such compounds in greater amounts.  This is how the kidneys play a major role in the homeostasis of the organism.  The kidneys also plays a vital role in the total water balance of the organism.  Varying their excretion of water in relation to the hydration status of the animal.

* 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]]

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

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

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

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

===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

====Outer Medulla====

====Outer Medulla====

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

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

=====The Outer Stripe=====

=====The Outer Stripe=====

This section located just inside the cortex contains the following parts of the [[The Nephron - Anatomy & Physiology| nephron]]:

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

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

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

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

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

* Renal Pyramids are important descriptor of part of the kidney.

* Renal Pyramids are important descriptor of part of the kidney.

**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.

**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 [[The Nephron - Anatomy & Physiology| nephrons]], [[WikiWords#Urinary Section| a medullary ray]] and [[Nephron Microscopic Anatomy #Collecting Duct| a collecting duct]].

* 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]].

* In some species the kidneys are described as '''multipyramidal''' this means they have multiple lobes and pyramids.  Others are described as '''unipyramidal''' meaning they only have one lobe and pyramid.

* In some species the kidneys are described as '''multipyramidal''' this means they have multiple lobes and pyramids.  Others are described as '''unipyramidal''' meaning they only have one lobe and pyramid.

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===

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.

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.

==Revision==

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

|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]]

|OVAM = [http://www.onlineveterinaryanatomy.net/content/urinary-system-and-comparative-kidneys A PowerPoint presentation on the urinary system and comparative kidneys.]

 

[[Category:Kidney - Anatomy & Physiology]]

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