The urinary system consists of the kidneys, ureters, bladder, and urethra, and it is responsible for filtering the blood and eliminating waste from the body in the form of urine. The kidneys contain millions of nephrons that filter blood to remove waste and regulate water and electrolyte levels. Urine is transported from the kidneys to the bladder via the ureters and is then excreted through the urethra. Diseases can impact kidney function and sometimes require dialysis or transplantation.

1. Urinary System
Can you hold it long enough for me to
get through this lecture?

2. QUICK REVIEW OF ELIMINATION
• Lungs eliminate CO2
• Sweat glands
eliminate excess
heat, salt
• Digestive tract-
indigestible solids,
bacteria
• Urinary tract is the
main system of
elimination

3. A little vocab
• Uria or Ur- urine
• Cyst- bladder
• Nephr or Ren- kidney
• Dys- painful

4. • Anuria
– Without urine
• Cystitis
– Inflammation of the bladder
• Dysuria
– Painful urination
• Hematuria
– Blood I urine
• Hydronephrosis
– > water in kidney
• Renal
– Pertaining to kidney

5. The Urinary Tract
• Urinary tract consists of 2
kidneys, 2 ureters, one
bladder and one urethra.
• Kidney location:
– Retroperitoneal
– Dorsal wall of abdominal
cavity
– 12th thoracic and 3rd lumbar
vertebrae
• Urethra
– 1.5 inches in women, 8 inches
in men

6. • Outer layer- Cortex
• Inner layer- Medulla
• Calyx- collects urine
as it is formed, join
together to form the
ureter

7. • Kidneys filter blood- 2, 000 L/day (500 gal)
– remove waste products and reabsorb water, other
valuable substances.
– 1.5 L of urine/day
• Metabolism produces toxic substances- esp
nitrogen containing waste as a by-product of
protein breakdown
• We eliminate nitrogen as urea- water soluble

8. • The main
functional unit of
the kidney is
called the
NEPHRON.
• 1 million per
kidney
• Most of nephron
located in renal
cortex
• Loop of Henle is
located in the
renal medulla

9. • Capillaries in glomerulus
filter blood- Bowman’
capsule collects ultra filtrate
• Through passive and active
diffusion, 95% of water is
reabsorbed, along with K,
Na, Ca
• Other things are actively
excreted, like drugs.
• Excretion is controlled by
hormones such as ADH
from hypothalamus

10. • Urine is made in 4
steps
2. Filtration
3. Reabsorption
4. Secretion
5. Excretion
A urinalysis is the most
common non-
invasive medical test
ordered

11. Diseases of the Kidney
• Acute Kidney failure- sudden loss of function
– Causes: nephritis, shock, injury, heart failure or
poisoning
– Symptoms: anuria or oliguria. Uremia, nausea,
coma, death
• Chronic Kidney failure- gradual loss of function
due to hypertension (high blood pressure) or
endocrine disease
• Cystitis- inflammation of the urinary bladder

12. Dialysis, Kidney transplant
• Hemodialysis- serves as an “artificial
kidney” 2-3x/week for 2-4 hours
• Peritoneal dialysis- uses patient’s own
peritoneal lining to filter blood
• Kidney transplant- need suitable donor.
Only need one, but must take anti-
rejection drugs for the life of the patient