THE URINARY SYSTEM Chapter 20 – Page 774

Function  Maintain homeostasis through composition, pH, and volume  Excretes foreign substances.

Structures of the System  Kidney’s – create urine by filtering the blood

Structures of the System  Ureters – carry urine from kidney to urinary bladder

Structures of the System  Urinary bladder – stores urine

Structures of the System  Urethra – tube emptying the urinary bladder

Catheter

Kidney Stones

Prevention  Drink enough water to form 2 quarts of urine in every 24-hour period.

Incontinence  The loss of bladder control  Temporary urinary incontinence  Alcohol  Caffeine  Over-hydration  Dehydration  Medication

Permanent Incontinence  After childbirth  Changes with aging  Hysterectomy  Enlarged prostate  Prostate cancer  Neurological disorders  obstructions

The Nephron

Structures of the Nephron Glomerulus: mechanically filters blood Bowman's Capsule: mechanically filters blood Proximal Convoluted Tubule: Reabsorbs 75% of the water, salts, glucose, and amino acids Loop of Henle: Countercurrent exchange, which maintains the concentration gradient Distal Convoluted Tubule: Tubular secretion of H ions, potassium, and certain drugs.

Kidney Functions (All occur in NEPHRONS 1,250,000 / kidney) Filtration - High pressure at the glomerulus filters:___ out of the blood into the filtrate a. Water b. Glucose c. Salts d. Amino Acids e. Urea

Kidney Functions (All occur in NEPHRONS 1,250,000 / kidney) Reabsorption (From filtrate) – Loop of Henle 99% water (178 liters/day) 100% glucose (180 g/day) 91% salts (1 300 g/day) 100% amino acids 50% urea

Kidney Functions (All occur in NEPHRONS 1,250,000 / kidney) Secretion (From blood stream to the distal tubule) - Uric acid - Creatine - H + - Ammonia

Kidney Functions (All occur in NEPHRONS 1,250,000 / kidney) Excretion (Collecting ducts carry urine toward ureters) a. Water b. Salts c. Uric acid d. Urea e. Ammonia f. Creatine

Urine Composition