Chapter 20: Urinary System

Urinary system

The body system responsible for removing waste products and maintaining fluid and electrolyte balance.

Kidneys

Bean-shaped organs that filter blood to form urine and regulate water, salt, and pH levels.

Nephron

The functional unit of the kidney responsible for filtering blood and forming urine.

Glomerulus

A network of capillaries in the nephron where blood filtration begins.

Bowman's capsule

A cup-shaped structure that surrounds the glomerulus and collects filtered fluid.

Renal tubule

The part of the nephron where reabsorption and secretion occur after filtration.

Proximal convoluted tubule

The first segment of the renal tubule where most reabsorption occurs.

Loop of Henle

The portion of the renal tubule that concentrates urine by reabsorbing water and salts.

Distal convoluted tubule

The final segment of the renal tubule involved in further ion exchange.

Collecting duct

A tube that receives urine from multiple nephrons and transports it to the renal pelvis.

Renal pelvis

The funnel-shaped reservoir in the kidney that collects urine and channels it to the ureter.

Ureter

A tube that carries urine from each kidney to the bladder.

Urinary bladder

A muscular sac that stores urine until it is excreted.

Urethra

A tube that carries urine from the bladder to the outside of the body.

Micturition (urination)

The process of expelling urine from the bladder through the urethra.

Filtration

The movement of fluid and dissolved substances from the glomerulus into Bowman’s capsule.

Reabsorption

The return of substances from the renal tubule to the blood.

Secretion

The transfer of substances from the blood into the renal tubule for excretion.

Urine

A liquid waste product formed by the kidneys and excreted through the urinary tract.

Antidiuretic hormone (ADH)

A hormone that increases water reabsorption in the kidneys.

Aldosterone

A hormone that promotes sodium and water reabsorption and potassium excretion by the kidneys.

Diuretic

A substance or medication that increases urine output.

Homeostasis (in urinary context)

The urinary system’s role in maintaining internal fluid, electrolyte, and acid-base balance.

Renin

An enzyme released by the kidneys that helps regulate blood pressure.

Erythropoietin (EPO)

A hormone produced by the kidneys that stimulates red blood cell production.

Urinalysis

A test that examines the content and characteristics of urine.

Glucosuria

The presence of glucose in the urine, often a sign of diabetes.

Hematuria

The presence of blood in the urine.

Proteinuria

The presence of abnormal amounts of protein in the urine.

Urinary tract infection (UTI)

An infection anywhere along the urinary tract, most commonly in the bladder or urethra.

Cystitis

Inflammation of the bladder, usually due to infection.

Urethritis

Inflammation of the urethra.

Pyelonephritis

A bacterial infection of the kidney and renal pelvis.

Renal failure

A condition in which the kidneys lose the ability to function effectively.

Hemodialysis

A treatment that uses a machine to filter waste from the blood when kidneys fail.

Kidney stones

Hard mineral deposits that form in the kidneys and may block urine flow.

Incontinence

The inability to control urination voluntarily.