Difference between revisions of "Urea"

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Also known as '''''Blood Urea Nitrogen — BUN
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| Also known as:
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|'''Blood Urea Nitrogen - BUN'''
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| See also:
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|'''[[Blood urea nitrogen - Reptiles|Urea in lizards]]'''
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==Description==
 
==Description==
 
Urea is a form of nitrogenous waste formed from [[Ammonia|ammonia]] via the urea cycle in the liver.  It freely crosses lipid membranes and is filtered into the glomerular filtrate in the renal glomerulus.  A proportion of this filtered urea is reabsorbed passively before final excretion and it forms a vital of the concentration gradient needed to prevent passive diuresis.
 
Urea is a form of nitrogenous waste formed from [[Ammonia|ammonia]] via the urea cycle in the liver.  It freely crosses lipid membranes and is filtered into the glomerular filtrate in the renal glomerulus.  A proportion of this filtered urea is reabsorbed passively before final excretion and it forms a vital of the concentration gradient needed to prevent passive diuresis.
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==Clinical Significance==
 
==Clinical Significance==
 
An increase in serum concentrations of urea and creatinine is known as '''[[Azotaemia|azotaemia]]''' and it is found almost exclusively in animals with kidney disease.
 
An increase in serum concentrations of urea and creatinine is known as '''[[Azotaemia|azotaemia]]''' and it is found almost exclusively in animals with kidney disease.
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*A diet with a low protein content or malnutrition.
 
*A diet with a low protein content or malnutrition.
  
 
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[[Category:Blood Biochemistry Changes]][[Category:To_Do_-_James]]
 
 
 
 
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[[Category:Blood Biochemistry Changes]][[Category:To_Do_-_Blood]]
 

Revision as of 19:41, 13 November 2010



Also known as: Blood Urea Nitrogen - BUN
See also: Urea in lizards

Description

Urea is a form of nitrogenous waste formed from ammonia via the urea cycle in the liver. It freely crosses lipid membranes and is filtered into the glomerular filtrate in the renal glomerulus. A proportion of this filtered urea is reabsorbed passively before final excretion and it forms a vital of the concentration gradient needed to prevent passive diuresis.

Clinical Significance

An increase in serum concentrations of urea and creatinine is known as azotaemia and it is found almost exclusively in animals with kidney disease.

Blood urea coentration may be elevated independently of creatinine for the following reasons:

  • Gastro-intestinal haemorrhage, as with gastro-duodenal ulceration.
  • Diet with high protein or purine content, such as liver.
  • Increased catabolism of body tissues, particularly muscle, which may occur in pyrexic animals or those with systemic disease.

Reduced urea concentration may occur due to: