Nitrogen Compounds Flashcards
What is renal disease?
When something is physically wrong with the kidneys, but the function may not be affected
What is renal failure?
When something is functionally wrong with the kidney, at least 75% of total nephron population is non-functional
What happens to the kidneys in renal failure?
The kidneys are no longer able to maintain the regulatory, excretory and endocrine functions required
What happens to hormone production to kidneys in renal failure?
The kidney produces less erythropoietin hormone, which results in anemia especially in cats
What is the result of renal failure?
It results in retention of nitrogenous solutes and derangement of fluid, electrolyte, and acid balance
What is azotemia?
A build up of waste in the blood due to failure of kidneys and an increased concentration of non-protein nitrogenous waste products in the blood
What us pre-renal azotemia?
A problem occurring before the kidney involving impaired blood flow to the kidney
What is pre-renal azotemia due to?
A decrease in glomerular filtration rate from circulatory disturbances causing decreased renal perfusion
What is renal azotemia?
A primary failure of the kidney which results from decreased GFR, check functionality with a specific gravity
What is post-renal azotemia?
When the urine does not leave the body and results from obstruction or rupture of urinary outflow tracts and hyperkalemia
What is uremia?
A condition involving abnormally high levels of waste products in the blood from a critical loss of functioning nephrons
What are the clinical signs of uremia?
- PU/PD
- Mild non-regenerative anemia
- Vomiting
- Weight loss
- Depression
What is ammonia?
Produced from dietary proteins and by catabolism of proteins and nitrogenous wastes in peripheral tissues
What converts amino acids and urea into ammonia?
Gastrointestinal micro-organisms in the colon and cecum which are then absorbed into the portal circulation
How much ammonia is shunted to the liver?
80-90% and then it is converted into urea via the urea cycle
What peripheral tissues metabolize 10-20% of ammonia?
The kidneys, heart and brain
How is ammonia measured?
With arterial blood collection and heparinized plasma samples
What can result of increased ammonia?
Ammonia is toxic to the CNS and is one cause of hepatic encephalopathy (damage to the CNS due to the build up of ammonia)
What could be a physiologic normal body function that would result in elevated ammonia?
A high protein diet, can also result in increase GFR and urea excretion
What kind of artifact may result in a increased ammonia?
It may not be an accurate number
What kind of disease may result in an increased ammonia level?
It can be a liver shunt, dehydration or a tumor
How is urea formed?
2 NH3 molecules are combined with 1 molecule of CO2
What is the chemical formula of urea?
CO(NH2)2
What is urea?
The end product of protein and amino acid catabolism
How is urea metabolized?
Synthesized in the liver using ammonia derived from amino acids
How is urea excreted?
By the kidneys which is the most important route of urea excretion
Where is urea filtered?
At the glomeruli and requires no metabolic work by the kidneys because glomerular filtration is driven by cardiac output
How is urea concentration measured?
As blood urea nitrogen, and is a screen for decreased GFR
What are the non-renal factors contributed to increased BUN?
- High protein meal
- Hemorrhage into gastrointestinal tract
- Increased catabolism (breakdown of protein)
- Drugs
What are the renal factors contributing to increased BUN?
- Pre-renal: shock, dehydration, congestive heart failure
- Primary: kidney is not functioning properly
- Post-renal: Urethral obstruction, ruptured bladder
What are some reasons that could contribute to a decreased BUN?
- Low protein diet
- Severe liver disease of portosystemic shunting
- Anabolic steroids due to building protein instead of breaking it down
What is creatinine?
Spontaneous, non-enzymatic breakdown product of phosphocreatine in muscle and is released into the blood from muscle at a constant rate
Which gender tends to have more creatinine?
Males due to higher muscle mass
Where is creatinine excreted?
By glomerular filtration and the rate of excretion is relatively constant and a good estimate of GFR
What is creatinine a measurement of?
It is a screen for decreased GFR?
What might be some reasons for increased creatinine?
- Non renal: massive muscle necrosis and prolonged strenuous exercise
- Pre-renal: shock, dehydration, congestive heart failure
- Post-renal: urethral obstruction, ruptured bladder
What does an increased BUN:creatinine ratio suggest?
Non-renal azotemia, may be due to an increased protein diet
What does a decreased BUN:creatinine ratio suggest?
Chronic liver failure
What are plasma proteins?
Total proteins consist of albumins and globulins, also includes fibrinogen
What could decreased plasma protein level indicate?
- Glomerular disease
- Liver disease
- Starvation
- Malabsorption
- Hemorrhage
What organ produces albumin?
The liver
What could a increased plasma protein level indicate?
- Severe dehydration
- Neoplasia (lymphoma and plasm
- Infection
What is albumin?
It contributes to plasma colloid oncotic pressure and synthesized in the liver and catabolized by all metabolically active tissues, serves as a carrier protein for many insoluble organize substances
What can contribute for hypoalbuminemia?
- Physiologic: low protein diet
- Increased loss: kidney, liver, gut and bleeding
- Catabolism
Where are globulins produced?
- Alpha and beta are synthesized by the liver, and gamma globulins are produced by b-lymphocytes and plasma cells
What does a high total protein with a normal A:G ratio indicate?
Dehydration
What does a high total protein with a low A:G ratio suggest?
Hyperglobulinemia
What us hyperglobulinemia?
Decreased gamma globulins are seen when there is a deficiency of immunoglobulins
