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PATHOLOGY OF THE URINARY SYSTEM
Pierre-Yves Daoust (AVC 410N, daoust@upei.ca)
Systemic Pathology I (VPM 221) Fall semester 2011
(http://atlantic.ccwhc.ca → people, for handouts and slides)
STRUCTURE AND FUNCTION
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the kidneys show significant anatomic variation among animal species:
externally: single organ, or distinct lobation; internally: unipyramidal or multipyramidal;
e.g.
dogs, cats, horses, small ruminants: unipyramidal kidney;
pigs: multipyramidal kidney, but no external lobation (like humans);
cattle: multipyramidal kidney, with external lobation;
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the renal parenchyma is divided into cortex, medulla and pelvis (papilla);
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20-25% of cardiac output passes
through the kidneys;
1,000-2,000 L of blood are filtered by the human kidneys daily (entire plasma volume about
100 times per day) → produce ~ 200 L of glomerular filtrate → > 99% reabsorbed by tubules
→ output of ~ l L of urine per day. In humans at rest, ~10% of the body’s energy
consumption is devoted to reabsorption necessitated by this high renal glomerular filtration
rate.
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Functional anatomy of the urinary system:
The kidney is the central organ involved in the maintenance of a constant extracellular environment
in the body. Its principal function is the regulation of
water and electrolyte balance; it also plays a
major role in the excretion of metabolic waste products. Its working principle is to produce a large
volume of protein-free glomerular filtrate from which it reabsorbs the constituents needed by the
body.
uriniferous tubule
