Non-Protein Nitrogens (Urea, Uric Acid, Creatinine & Ammonia) Flashcards
4 types of Non-Protein Nitrogens
- Urea
- Creatinine
- Uric Acid
- Ammonia
NPN with the HIGHEST concentration in the blood
Urea
Major excretory product of protein metabolism.
Urea
Ammonia is bound with Carbon Dioxide to form
Carbamoyl Phosphate
This enzymatically catalyzed process is also an important pathway to reduce the levels of ammonia in the blood.
Urea Cycle
Urea is commonly termed as?
Since?
Blood Urea Nitrogen (BUN) since urea was based on the measurement of your Nitrogen
- Most of the urea in the glomerular filtrate is excreted in the ____________
- Some urea is reabsorbed by ________________ during passage of the filtrate through the renal tubules.
- Urine
- Passive Diffusion
Formula for Urea
BUN x 2.14
Protein will undergo ___________ to get amino acids.
Proteolysis
Amino acids will undergo _____________ or oxidative deamination to get ammonia
Transamination
- Transfer of your amino group
- Removal of your amino group
- Transamination
- Oxidative deamination
Urea is formed in the liver, especially in the __________
Hepatocytes
- A portion of your hepatocytes where the forming of Urea BEGINS
- A portion of your hepatocytes where the forming of Urea ENDS
- Mitochondria
- Cytoplasm
CO2 and NH3 is converted into
Carbamoyl Phosphate
The enzyme to catalyze carbamoyl phosphate is?
Carbamoyl Phosphate synthetase 1
Carbamoyl Phosphate will combine with ___________ to form ______________
- ornithine
- citrulline
the enzyme to catalyze Citrulline is
Ornithine transcarbamylase
another importance of the Urea Cycle is to prevent the accumulation of _________
Ammonia
2 Areas where your Urea can be excreted
- Kidneys
- GI tract (Gastro Intestinal)
90%, is present and can be detected in urine
Kidneys
10%, through the action of the bacteria, urea will be converted back to ammonia which then be reabsorbed and recycled in the liver
GI tract
Concentration of urea in the blood is affected by the:
- Protein content of the diet
- Rate of protein metabolism
- Renal function and Perfusion
Passage of your fluid through your blood vessels to an organ or tissue.
Perfusion
2 types of Urea Disorders
- Azotemia
- Uremia
Elevation of urea in the blood
Azotemia
Azotemia + renal failure
Uremia
3 causes of Azotemia in the blood:
- Prerenal
- Renal
- Postrenal
Occurs as a result of reduced renal blood flow
Prerenal
Occurs as a result of decreased renal function
Renal
Occurs due to obstruction of urine flow anywhere in the urinary tract by renal calculi, tumors of the bladder or prostate, or severe infection.
Postrenal
5 examples of Prerenal Azotemia
- Congestive Heart failure
- Shock, hemorrhage
- Dehydration
- Increased protein catabolism
- high-protein diet
2 examples of Renal Azotemia
- Acute and chronic renal failure
- Renal disease, glomerular nephritis and tubular necrosis
Inflammation in your glomerulus;
no proper filtration of urea
Nephritis
Death in body tissue;
tubules cannot reabsorb properly
Necrosis
1 Example of a Postrenal Azotemia
Urinary tract obstruction
4 causes of decreased concentration of Urea
- Low protein intake
- Severe vomiting and diarrhea
- Liver disease
- Pregnancy (due to hormonal changes)
Normal BUN/Creatinine ratio
10:1 to 20:1
Formed from creatine and creatine phosphate in the muscle;
Released to the plasma in proportion to muscle mass
Creatinine
Creatinine is synthesized by 3 amino acids which are:
- Arginine
- Glycine
- Methionine
The 3 Amino acids will undergo transamination forming:
Guanidinoacetic acid
The transamination between the 3 amino acids and guanidinoacetic acid is catalyzed by the enzyme:
L-Arginine:glycine amidinotransferase (AGAT)
Creatine with the help of creatine kinase will form phosphocreatine aka ____________
Creatine Phosphate
Creatinine is a byproduct of ________ and ___________
Creatine & Phosphocreatine
3 Clinical applications of Creatinine measurement
- Determine the sufficiency of kidney function
- Determine the severity of kidney damage
- Monitor the progression of kidney disease
4 reasons why Creatinine is a nice measurement.
- it is filtered by the glomerulus
- it is neither reabsorbed nor secreted
- relatively constant in the plasma/blood
- not affected by anything unlike urea that is affected by diet
3 Muscle diseases on Creatinine:
- Muscular dystrophy
- Poliomyelitis
- Trauma
It is the progressive weakness and loss of muscle mass
Muscular dystrophy
It affects our spinal cord that can cause paralysis
Poliomyelitis
Product of the catabolism of PURINE NUCLEIC ACIDS (Guanine & Adenosine)
Uric Acid
Relatively insoluble in plasma and in high concentrations, can be deposited in the joints and tissue causing pain and inflammation
Uric Acid
Example of an inflammation caused by Uric Acid
Gouty Arthritis
5 causes in increased concentration of Uric Acid
- Gout
- Treatment of myeloproliferative disease with cytotoxic drugs
- Hemolytic and proliferative processes
- Purine-rich diet
- Increased tissue catabolism and starvation
8 diseases caused by Enzyme deficiencies on uric acid:
- Lesch-Nyhan syndrome
- Phosphoribosyltransferase synthetase deficiency
- Glycogen storage disease type-1
- Fructose intolerance
- Toxemia in pregnancy
- Lactic acidosis
- Chronic renal disease
- Drugs and poisons
4 causes in decreased concentration of Uric Acid
- Liver disease
- Defective tubular reabsorption
- Chemotherapy with Azathioprine
- Overtreatment with allopurinol
Pain and inflammation of the joints due to precipitation of monosodium urates
Gout
Produced in the deamination of amino acids during protein metabolism
Ammonia
Consumed by the parenchymal cells of the liver in the production of urea.
Ammonia
3 clinical application of ammonia measurement
- Hepatic failure
- Reye’s syndrome
- Inherited defects in the urea cycle
Disease that is common in children;
Acute metabolic disorder of the liver;
A child’s blood sugar would typically drop, while the level of ammonia and acidity in The body would increase;
Liver may swell and may develop fatty deposits
Reye’s syndrome
Cerebral Edema;
Intracranial HTN;
Neuronal Dysfunction
Hepatic Encephalopathy
The result of overproduction of uric acid and may be exacerbated by a purine-rich diet, drugs, and alcohol
Hyperuricemia
Less common than hyperuricemia and is usually secondary to severe liver disease or defective tubular reabsorption.
Hypouricemia
