URINARY SYSTEM

Urinary System

Function = to form and eliminate urine Consists of:

Two kidneys Organs of excretion Regulate body fluids’ composition, volume, and pH Produce erythropoietin Produce renin

Two ureters Urinary bladder Urethra

The Kidneys

Located behind peritoneum in lumbar region

Adrenal glands rest on top Outer region = renal cortex Inner region = renal medulla Nephrons: Microscopic working units

of kidneys

Urine Formation

Blood pressure forces material through glomerular wall and capsule, into nephron

Glomerular filtrate consists of: Water Electrolytes Soluble wastes Nutrients Toxins

Urea = main waste material (byproduct of protein metabolism)

Urine Formation (con’t)

Waste material and toxins need to be eliminated

Water, electrolytes, nutrients returned to blood

Remaining fluid is urine Adjusted by pituitary hormone ADH

Removal of Urine

Urine Drained from renal pelvis Carried by ureter to urinary bladder before

release Urethra

Expulses urine when bladder muscle contracts Sphincters

Regulate urination Upper has involuntary function Lower functions under conscious control

Clinical Aspects of the Urinary System

Infections of urinary tract Organisms usually enter through urethra Usually colon bacteria in feces UTI’s more common in females Cystitis produced

Infections (con’t)

Infections of kidney and renal pelvis Pyelonephritis Symptoms include:

Dysuria Bacteriuria Pyuria

Urethritis Inflammation of urethra Associated with sexually transmitted diseases

Glomerulonephritis

Inflammation of kidney and glomeruli Specifically occurs after immunologic reaction Usually response to infection in another system Symptoms:

Hypertension Edema Oliguria (passage of small amounts of urine)

Dialysis

Hemodialysis = Cleansing of blood cleansed Passed over membrane surrounded by dialysate to

remove unwanted substances Peritoneal dialysis = fluids introduced to

peritoneal cavity Periodically withdrawn with waste products Process repeated

Urinary Stones (calculi)

Called urinary lithiasis Formed of calcium salts May result from:

Dehydration Infection Abnormal urine pH Urinary stasis Metabolic imbalances

Urinalysis

Simple, widely-used diagnosing process Urine examined and tested for:

Color Turbidity Specific gravity pH level Chemical components Cells, crystals, or casts