Urinary System 1 Functions 1 Excretion 2 Elimination

Urinary System 1

Functions 1. Excretion 2. Elimination 3. Homeostatic Regulation 2

Metabolic Wastes 1. Urea 2. Creatinine 3. Uric Acid 3

Urinary System v Kidney regions: 1. Cortex Ø Ø Ø Direct filtration cortical nephrons juxtamedullary nephrons 2. Medulla Ø 3. Reabsorption, Secretion Pelvis excretion 4

Overview of Urinary System n 1. 2. 3. Flow Filtration Reabsorption Secretion 5

Glomerular Filtration n Filtration membrane n Net Filtration Pressure: n n Glomerular hydrostatic pressure (HPg) (GBHB) Colloid osmotic pressure (OPg) (BCOP) Capsular hydrostatic presure (HPg) (CHP) Glomerular Filtration Rate (GFR) 6

Tubular Reabsorption n Reabsorption of organic nutrients n Reabsorption of ions, water, and some molecules. n Water reabsorption - osmotic changes due to active transport of sodium ions. n Molecule reabsorption - secondary active transport initiated by ions. Types of Active Transport 1. Co-transport 2. Countertransport 7

Types of carrier mediated transport 1. Facilitated diffusion 2. Active Transport (secondary active) 1. Cotransport (symport) 2. Countertransport (antiport) 8

Tubular Secretion n Disposes of unwanted solutes Regulation of Urine Concentration and Volume • countercurrent mechanism • osmotic gradients • Diuretics 9

Maintaining Homeostasis Balances: Water/salt p. H Blood pressure 10