Non-Protein Nitrogens (NPNs)

Urea

The NPN present in the highest concentration in blood

• Major excretory product of protein metabolism

Glomerulus

After urea is carried in the blood to the kidney, it is then readily filtered from the plasma by the:

• Renal function and perfusion

• Protein content of your diet

• Rate of protein catabolism

The concentration of urea in the plasma is determined by:

Azotemia

An elevated concentration of urea in the blood is termed:

Uremia

Very high plasma urea concentration accompanied by renal failure is called:

Distal tubules

Uric acid is filtered by the glomerulus and secreted by the ____________ in the urine.

Proximal tubules

Urea is mostly reabsorbed in:

• Liver disease

• Defective tubular reabsorption (Fanconi)

• Chemotherapy

• Allopurinol overtreatment

Decreased concentration of urea

Creatinine / Creatine

It is excreted in plasma at a constant rate related to muscle mass

10:1 to 20:1

What is the normal BUN/Creatinine ratio?

>20:1

In prerenal disease, the BUN/Creatinine ratio can reach:

True renal disease

Both BUN and creatinine rise together in:

Ammonia

Formed through the deamination of amino acids during protein metabolism

Free ammonia

What type of ammonia is toxic?