Orina

Orina, commonly referred to in English as urine, is a liquid waste produced by the kidneys as part of the body's regulation of fluid balance, electrolyte levels, and toxin elimination. It is mainly water but contains dissolved substances such as urea, creatinine, uric acid, electrolytes (sodium, potassium, chloride), and various organic compounds. In healthy adults, daily urine production typically ranges from about 0.9 to 2.0 liters, influenced by fluid intake, environment, diet, and metabolic state.

Formation and flow: Urine is produced through kidney processes that begin with filtration of blood in the glomeruli. The filtrate then undergoes reabsorption and secretion in the renal tubules, yielding a concentrated final urine that drains into the collecting ducts and the renal pelvis. From there it travels via the ureters to the bladder and is excreted through the urethra during urination.

Physical characteristics: Urine is usually pale yellow and clear, with color and odor affected by hydration, diet, medications, and health. Normal pH ranges roughly from 4.5 to 8. Specific gravity typically falls between about 1.005 and 1.030.

Clinical relevance: Urinalysis is a common diagnostic tool. Routine testing examines color, clarity, odor, pH, specific gravity, and the presence of substances such as protein, glucose, ketones, blood, bilirubin, nitrites, and leukocytes. Microscopic examination can reveal cells, crystals, bacteria, or casts. Abnormal findings may indicate urinary tract infections, kidney disease, diabetes, liver disorders, dehydration, or other medical conditions.

Collection and handling: Urine samples may be random, clean-catch midstream, or 24-hour collections. Proper labeling and appropriate storage or prompt analysis are important to ensure reliable results. The term orina is used in several languages for urine; in English the term is urine.