The core vocabulary of the kidneys, bladder and urinary tract — defined in clear English for healthcare learners.
Last updated: September 9, 2026
The urinary system filters the blood and removes waste as urine. This page defines the essential terms in plain English, from anatomy to common conditions and procedures.
| Term | Definition |
|---|---|
| Kidney | The organ that filters blood to produce urine. |
| Nephron | The kidney’s tiny filtering unit. |
| Ureter | The tube carrying urine from a kidney to the bladder. |
| Bladder | The organ that stores urine. |
| Urethra | The tube carrying urine out of the body. |
| Glomerulus | The cluster of tiny vessels in a nephron where filtering begins. |
| Urea | A waste product filtered from the blood into the urine. |
| Creatinine | A waste product used to measure kidney function. |
| Dialysis | A treatment that filters the blood when the kidneys fail. |
| Hematuria | Blood in the urine. |
| Proteinuria | Excess protein in the urine. |
| Dysuria | Painful or difficult urination. |
| Oliguria | Abnormally low urine output. |
| Polyuria | Excessive urine output. |
| Incontinence | A loss of bladder control. |
| Nephritis | Inflammation of the kidney. |
| Pyelonephritis | A kidney infection. |
| Cystitis | Inflammation of the bladder, usually from infection. |
| Nephrolithiasis | Kidney stones. |
| Renal failure | A loss of the kidneys’ ability to filter blood. |
| Cystoscopy | A camera examination of the bladder. |
| Nephrectomy | Surgical removal of a kidney. |
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Yes. This vocabulary is core to US health programs — nursing school and NCLEX prep, pre-med, and medical assistant training. MediLearn lets you drill these terms with quizzes and flashcards using spaced repetition.
The organ that stores urine.
Painful or difficult urination.
Inflammation of the bladder, usually from infection.