Difference between revisions of "Urea"
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| − | Also known as '''''Blood Urea | + | {{unfinished}} |
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| + | {| cellpadding="10" cellspacing="0" border="1" | ||
| + | | Also known as: | ||
| + | |'''Blood Urea Nitrogen - BUN''' | ||
| + | |- | ||
| + | | See also: | ||
| + | |'''[[Blood urea nitrogen - Reptiles|Urea in lizards]]''' | ||
| + | |} | ||
==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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Reduced urea concentration may occur due to: | Reduced urea concentration may occur due to: | ||
*Over-enthusiastic fluid therapy, diluting the urea present in the blood. | *Over-enthusiastic fluid therapy, diluting the urea present in the blood. | ||
| − | *Disease that cause polyuria and/or polydipsia may cause 'medullary washout' of urea. Common examples include pyschogenic polydipsia, [[Diabetes Insipidus|diabetes insipidus]] and [[Hyperadrenocorticism|Cushing's disease]]. | + | *Disease that cause polyuria and/or polydipsia may cause 'medullary washout' of urea. Common examples include pyschogenic polydipsia, [[Diabetes Insipidus|diabetes insipidus]] and [[Canine Hyperadrenocorticism - Cushing's Disease|Cushing's disease]]. |
*Reduced synthesis with [[Portosystemic Shunt|porto-systemic shunts]], [[Hepatic Microvascular Dysplasia|microvascular dysplasia]] or liver failure. | *Reduced synthesis with [[Portosystemic Shunt|porto-systemic shunts]], [[Hepatic Microvascular Dysplasia|microvascular dysplasia]] or liver failure. | ||
*A diet with a low protein content or malnutrition. | *A diet with a low protein content or malnutrition. | ||
| − | + | [[Category:Blood Biochemistry Changes]][[Category:To_Do_-_James]] | |
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| − | [[Category:Blood Biochemistry Changes]][[Category:To_Do_- | ||
Revision as of 12:23, 13 October 2010
 |
This article is still under construction. |
| 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:
- Over-enthusiastic fluid therapy, diluting the urea present in the blood.
- Disease that cause polyuria and/or polydipsia may cause 'medullary washout' of urea. Common examples include pyschogenic polydipsia, diabetes insipidus and Cushing's disease.
- Reduced synthesis with porto-systemic shunts, microvascular dysplasia or liver failure.
- A diet with a low protein content or malnutrition.