Anatomy & Physiology
A practical map of the body's structures and systems
Lesson 18 of 20
Urinary system
The urinary system filters blood, removes certain wastes, and helps regulate fluid, electrolytes, and acid-base balance. The kidneys form urine through filtration and selective reabsorption and secretion. Urine travels through ureters to the bladder and exits via the urethra. Kidney function also contributes to blood pressure regulation and red-cell production signaling.
Key points
- Each kidney contains nephrons that filter blood and adjust the forming urine.
- Glomerular filtration moves water and small solutes into a nephron's tubule.
- Selective reabsorption returns needed substances from tubular fluid to blood.
- Ureters carry urine to the bladder; the urethra carries it out of the body.
- The kidneys help regulate blood volume and contribute to erythropoietin production.
Key terms
- Nephron
- Functional microscopic unit that forms urine in the kidney.
- Glomerulus
- Capillary network where filtration into the nephron begins.
- Ureter
- Tube carrying urine from a kidney to the bladder.
- Urethra
- Passage carrying urine from the bladder to the exterior.
- Reabsorption
- Return of filtered water or substances from a nephron tubule to blood.
Memory tip
Ureters arrive at the bladder; the urethra exits it.
Clinical note
Support client comfort and privacy; urinary symptoms should be referred to an appropriate clinician.
Unit checkpoint
Lock it in: match the terms, then test yourself.