Urinary System

Urinary System

1. Five Major Functions

   • Excretion
   • Secretion of Hormones
   • Balance Electrolytes
   • Maintenance of pH balance
   • Regulation of water content of blood

2. Urine Formation

   • 1: Glomular Filtration: BP forces water, gluccose, amino acis, salts, urea, etc from glomerulus into bowman's capsule
   • 2: Tubular Reabsorption: Diffusion and Active Transport return water, glucose, amino acid, salts to blood at proximal convoluted tubule
     • Na actively absorbed, Cl passively follows
   • 3: Tubular Secretion: Active Transport moves H+ ions and creatinine from blood into distal convoluted tubule
     • MORE H+ ION secreted = LOWER pH

3. Hormonal Regulation of Water- Salt Balance

   • ADH: decreased ADH = lower water absorption, lower BP, and higher urine output
     • -produced by hypothalamus (regulated by thirst receptors), released by pituitary gland, INCREASED BP = DECREASED urine output
   • ANH (atrial natriuretic hormone): promotes Na+ and water EXCRETION to DECREASE BP
   • Aldosterone: produced by adrenal cortex, REABSORPTION of Na+ and water to INCREASE BP

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