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The Urinary System
Chapter 26
Functions
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Regulating blood volume and blood pressure
Regulated concentration of sodium, potassium,
chloride, etc.
Stabilizes blood pH
Conserves nutrients and gets rid of waste
Assists liver in detoxifying poisons
Organization
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Excretion- removal of waste from body fluids
Elimination- discharge of these wastes from
the body
Kidneys
Ureters
Urinary bladder
Urethra
Kidneys
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Hilus- medial indentation, location of entry
and exit of renal artery and vein
Nephron- microscopic tubular structures,
begins process of urine production, 1.25
million in each kidney
Nephron
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Renal Corpuscle- region called Bowman’s
capsule, which is a network of capillaries
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Blood pressure forces fluid and dissolved solutes
out of the capillaries
The filtrate enters the renal tubule
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Reabsorption of useful organics, 90% of the water
Secretion of any waste products
Renal Physiolgy
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Urea- most abundant organic waste, created by
the breakdown of amino acids
Creatinine- generated by the breakdown of
creatine phosphate, used in muscle contraction
Uric acid- formed from nitrogenous bases of
RNA
Water must be used to get rid of these waste
products
Control of Urine Volume
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Regulated by reabsoption of water
ADH (anti-diuretic hormone)- highter
circulating levels increase amount of
reabsorption of water
Composition of normal urine
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pH = 6
Water = 93-97%
Color = clear yellow