1. Chapter 20
Urinary System

2. Function Waste removal Maintains water and electrolyte balance
Regulates pH

3. Structure 2 Kidneys Reddish brown Bean shaped
Lateral to vertebral column
Structure
Cortex – outer edge
Medulla – internal tissue containing nephrons
Nephrons – tiny tubules that allow kidneys to function

4. Structure Continued

5. Structure Continued 2 Ureters – tube from each kidney to the bladder
Bladder – holding tank
Urethra – tube to the outside of the body

6. Urine Formation Nephrons Regulate water and electrolyte concentrations
Remove waste from the blood

7. Urine Formation Continued
Urine Content Not Found in Plasma
Urea – breakdown of amino acids
Uric Acid – by product of amino acid metabolism
High sulfate
High phosphate
*All glucose is supposed to get reabsorbed
*95% water

8. Water Intake Water Output
30% = moist food
10% = metabolism
Regulated by thirst
Hypothalamus
Water loss = increase in extracellular osmotic pressure
Thirst occurs at 1% of total body (or when the body is dehydrated by 1%)
60% = urine
6% = feces
6% = sweat
28% = evaporation from skin/breathing
Regulated by urine production
ADH (antidiuretic hormone) present

9. Electrolyte Intake
Electrolyte Output
Food
Beverages
Metabolic reactions
Salt cravings
Sweat
Feces
Kidney and urine production
Hormone aldosterone (controls water excretion)