1. The Urinary System

2. Functions of the Urinary System
Elimination of waste products
Nitrogenous wastes
Toxins
Drugs
Regulate aspects of homeostasis
Water balance
Electrolytes
Acid-base balance in the blood
Blood pressure
Releases erythropoietin

3. Urinary System Two Kidneys Two Ureters Urinary Bladder Urethra
Perform all filtering functions (but not excretion)
Two Ureters
Bring urine from Kidneys to Urinary Bladder
Urinary Bladder
Holds Urine until excretion
Can stretch
Urethra
Moves urine from bladder to outside of body

4. Organs of the Urinary System
kidneys
ureters
Organs of the Urinary System
urinary bladder
urethra

5. Kidney Location Against the dorsal body wall (retroperitoneal)
Superior dorsal region
(T12 to L3)
The right kidney is slightly lower than the left (due to position of the liver)
*An adrenal gland sits atop each kidney

6. Kidney Anatomy (External)
Renal hilum (hilus- singular)
A medial indentation where several structures enter or exit the kidney (ureters, renal artery, renal vein)

7. Coverings of the Kidneys
Renal Capsule
Surrounds each kidney
Perirenal fat capsule
Surrounds the kidney and cushions against blows
Renal fascia
Outermost capsule that helps hold the kidney in place against the muscles of the trunk wall

8. Regions of the Kidney(Internal)
Renal cortex—outer region
Renal medulla—inside the cortex
Renal pelvis—inner collecting tubes, lead to the ureter

9. Internal Kidney Structures
Renal or medullary pyramids -triangular shaped striped regions of tissue in the medulla
Calyx(ces) -cup-shaped structures, drain urine from pyramids into pelvis
Renal columns -extensions that separate the pyramids in the medulla

10. Figure 15.2b

11. Blood Supply
One-quarter of the total blood supply of the body passes through the kidneys each minute