Changes

Also known as '''''Blood Urea Nitrogen — BUN

 

| Also known as:

|'''Blood Urea Nitrogen - BUN'''

==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.

==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.

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 [[Canine Hyperadrenocorticism - Cushing's Disease|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 [[Hyperadrenocorticism|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_Sample]][[Category:Dog]][[Category:Cat]][[Category:Cattle]][[Category:Sheep]][[Category:Horse]][[Category:Pig]][[Category:Donkey]][[Category:To_Do_-_James]]

 

 

 

[[Category:Blood Biochemistry Changes]][[Category:To_Do_-_Blood]]