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.

===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

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===

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

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

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

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

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[[Category:Kidney - Anatomy & Physiology]]

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