Memmler’s A&P

Chap 22The Urinary System

The urinary system p464

• Excretion• Systems active in excretion– Urinary system– Digestive system– Respiratory system– Integumentary system

Organs of urinary system p464• Two kidneys• Two ureters• One urinary bladder• One urethra

Functions of the kidneys p464• Excretion• Water balance• Acid-base balance • Blood pressure regulation• Regulation of red blood cell production

The kidney 465

• Located in retroperitoneal space

• Divided into 2 regions: – Renal medulla– Renal cortex

• Nephrons: functional unit of kidneys

The Nephron p466

• Glomerulus • Convoluted tubule• Peritubular

capillaries • Blood pressure is

the force that causes filtration.

Formation of urine p470• Glomerular filtration• Tubular reabsorption• Tubular secretion• Concentration of urine

Glomerular filtration p468

Formation of urine p468

Renal control of blood pressure p471• Renin: initiates the process that activates

angiotensin, a protein made by the liver that elevates blood pressure.

• Angiotensin: promotes the release of aldosterone and ADH and stimulates thirst, raising blood pressure by increasing blood volume.

p471-472

•Ureters •Urinary bladder•Urethra

Urine p473• Normal constituents– Nitrogenous waste

products (urea, creatinine)– Electrolytes– Pigment

Measure of dissolved substances in urine is called specific gravity

• Abnormal constituents– Glucose (glucosuria)– Albumin (proteinuria)– Blood (hematuria)– Ketones– WBCs (pyuria) – Casts (in larger numbers)

Disorders of urinary system p474• Kidney stones (renal calculi) treated by lithotripsy• Renal failure: chronic or acute– Acute renal failure: fast onset– Chronic renal failure: slow gradual loss of function

• Symptoms of chronic renal failure:– Dehydration– Edema– Electrolyte imbalance– Hypertension– Anemia– Uremia

Dialysis p475 • Hemodialysis• Peritoneal

dialysis

Disorders p477• Cystitis• Tumors• Urinary incontinence – Stress incontinence– Urge incontinence– Overflow incontinence– Enuresis

• Urethritis• Cystoscopy

Effects of aging p479• Kidneys lose some of their ability to concentrate

urine• Decrease in number and size of nephrons• Elderly people get more urinary tract infections than

young people: confusion• Prostatic hypertrophy• Decreased muscle tone in bladder and urinary

sphincters: urinary incontinence

Incontinence

Catheterization