Urine Composition and Components

Urine Composition

• Urine consists of 95% water and 5% solutes.

Organic Composition

• Key organic components include urea, creatinine, uric acid, hippuric acid, and various other substances.

Inorganic Composition

• Major inorganic components are sodium chloride, potassium, sulfate, phosphate, ammonium, magnesium, and calcium.

Urea

• A significant metabolic waste produced in the liver from protein and amino acid breakdown; accounts for 60-90% of nitrogenous waste in urine.

Creatinine

• A nitrogenous byproduct found in muscle tissue, indicative of muscle metabolism.

Uric Acid

• A precursor to kidney stones; results from nucleic acid breakdown in food and during cellular decomposition.

Hippuric Acid

• A compound formed from benzoic acid, excreted in higher amounts with vegetarian diets.

Other Substances

• Urine may also contain small quantities of carbohydrates, pigments, fatty acids, mucin, enzymes, and hormones.

Sodium Chloride

• The primary salt in urine, levels fluctuate according to dietary intake.

Potassium

• Present in urine mainly as chloride, sulfate, and phosphate salts.

Sulfate

• Derived from the metabolism of amino acids.

Phosphate

• Mainly exists as sodium compounds that help balance pH in the blood.

Ammonium

• Comes from protein metabolism and glutamine in kidneys; its concentration varies with blood and fluid acidity.

Magnesium and Calcium

• Both minerals are found as chloride, sulfate, and phosphate salts in urine.

Normal Daily Volume

• Typical urine output ranges from 1200 to 1500 mL per day.

Normal Day/Night Ratio

• Urine production is often at a 2:1 or 3:1 ratio during the daytime compared to nighttime.

Diuresis

• Refers to the increased production of urine.

Polyuria

• Defined as urine output exceeding 2000 mL per day.

Oliguria

• Characterized by reduced urine output, which indicates potential health issues.