Changes

==Reptile==

==Reptile==

===Gross Renal Anatomy of Lizards===

====Gross Renal Anatomy of Lizards====

Two kidneys are present in lizards but the caudal aspect of them is fused in many species.  Also the presence of a urinary bladder is species specific.

Two kidneys are present in lizards but the caudal aspect of them is fused in many species.  Also the presence of a urinary bladder is species specific.

===Gross Renal Anatomy of Snakes===

====Gross Renal Anatomy of Snakes====

* Snakes have paired kidneys with the right being most cranial.   

* Snakes have paired kidneys with the right being most cranial.   

** Urine is stored in either the distal colon or flared ends on each urethra

** Urine is stored in either the distal colon or flared ends on each urethra

===Gross Renal Anatomy of Chelonians===

====Gross Renal Anatomy of Chelonians====

Chelonians have an osmotically permeable bladder which can reabsorb water.  This structure acts as a buoyancy aid in aquatic turtles and helps reabsorb sodium.  Some species have paired accessory bladders off the main structure

Chelonians have an osmotically permeable bladder which can reabsorb water.  This structure acts as a buoyancy aid in aquatic turtles and helps reabsorb sodium.  Some species have paired accessory bladders off the main structure

===Microscopic Renal Anatomy of Reptiles===

====Microscopic Renal Anatomy of Reptiles====

Reptiles have no pelvis, pyramids, cortex or medulla and kidney is only made up of a few thousand nephrons with poorly developed glomeruli.  Few capillaries supply the kidneys and the nephrons have no loop of henle.  In squamate males a sexual segment between the distal tubule and collecting ducts is present.

Reptiles have no pelvis, pyramids, cortex or medulla and kidney is only made up of a few thousand nephrons with poorly developed glomeruli.  Few capillaries supply the kidneys and the nephrons have no loop of henle.  In squamate males a sexual segment between the distal tubule and collecting ducts is present.

===Nitrogenous Waste===

====Nitrogenous Waste====

Reptiles excrete nitrogenous waste mainly in the form of uric acid.  It is suspended in spheres complexed with protein and sodium (carnivorous diet) or potassium (herbivorous diet) along with mucoid substances (glycoprotein and mucopolysaccharides).  As a result their urine contains large quantities of protein.

Reptiles excrete nitrogenous waste mainly in the form of uric acid.  It is suspended in spheres complexed with protein and sodium (carnivorous diet) or potassium (herbivorous diet) along with mucoid substances (glycoprotein and mucopolysaccharides).  As a result their urine contains large quantities of protein.

===Uric Acid Secretion in Reptiles===

====Uric Acid Secretion in Reptiles====

Uric acid is secreted into the proximal tubules actively using potassium and into the bladder (where present) is response to H<sup+</sup> secretion.  The secretion of urate increases in response to a decrease in blood pH.  

Uric acid is secreted into the proximal tubules actively using potassium and into the bladder (where present) is response to H<sup+</sup> secretion.  The secretion of urate increases in response to a decrease in blood pH.  

In the urodeum urine moves via reverse peristalsis to the rectum where some protein is reabsorbed to be recycled

In the urodeum urine moves via reverse peristalsis to the rectum where some protein is reabsorbed to be recycled

===Post Renal Urine Modification in Reptiles===

====Post Renal Urine Modification in Reptiles====

Voided urine is not reflective of kidney function due to the transport of ions and water across the colon wall and the reabsorption of sodium / excretion of potassium and urates in the bladder.

Voided urine is not reflective of kidney function due to the transport of ions and water across the colon wall and the reabsorption of sodium / excretion of potassium and urates in the bladder.

===Reptilian Renal Adaptations for Water Conservation===

====Reptilian Renal Adaptations for Water Conservation====

* Very few nephrons therefore low GFR

* Very few nephrons therefore low GFR

* Water is reabsorbed from urine in the colon

* Water is reabsorbed from urine in the colon

===Reptilian Response to Dehydration===

====Reptilian Response to Dehydration====

* The afferent arteriole collapses in response to increased levels of arginine vasotocin

* The afferent arteriole collapses in response to increased levels of arginine vasotocin

* Renal portal blood perfuses the tubules

* Renal portal blood perfuses the tubules

===Reptilian Renal Portal System===

====Reptilian Renal Portal System====

* Similar to that of birds

* Similar to that of birds

* The renal portal vein bypasses the glomeruli of the kidneys

* The renal portal vein bypasses the glomeruli of the kidneys

*** Blood bypasses kidney

*** Blood bypasses kidney

===Reptilian Salt Glands===

====Reptilian Salt Glands====

* Similar to birds

* Similar to birds

* Sea turtles have modified tear glands which allow them to secrete salt from their eyes

* Sea turtles have modified tear glands which allow them to secrete salt from their eyes

===Other Roles of the Reptilian Kidney===

====Other Roles of the Reptilian Kidney====

* Activates vitamin D

* Activates vitamin D

* Synthesises Vitamin C

* Synthesises Vitamin C