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Renal System

The renal system consists of:

  • The kidneys and their constituent nephrons.
  • The ureters.
  • The urinary bladder.
  • The urethra.

Duties of the renal system include:

  • Alter amount and composition of urine to maintain blood volume and electrolyte levels.
  • Excrete soluble waste.
  • Produce erythropoietin for red blood cell formation.
  • Activate vitamin D for calcium absorption.

Damage to the renal system usually follows three phases:
1. Oliguria due to damaged tissue and low glomerular filtration rate.
2. Polyuria due to immature replacement tissue.
3. Convalescence as function returns to normal.

Nephrons

The functional unit of the kidney.

% of kidney function is determined by the % of nephrons remaining. Test of kidney function use the blood urea nitrogen/serum creatinine ratio.

Renal function remains intact, and so loss is difficult to diagnose, so long as > 25% of nephrons remain. Otherwise...

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