Urinary System

Urinary System

1. Kidneys

   • 2x large, reddish, bean-shaped organs
   • located on the posterior abdominal wall
   • 2 parts encapsulated by a dense irregular connective tissue capsule
     • Outer Cortex
     • Medulla
   • Highly vascularized
   • medially-located renal hilum
     • Ureters
       • Moves urine from the kidneys to the bladder
         • Mucosa is distensible
           • transitional epithelium and a fibroelastic lamina propria
           • Muscularis externa
             • undergoes rhythmic peristaltic contractions to move urine down the ureter towards the bladder
             • an inner longitudinal layer
             • outer circular layer
             • consists of smooth muscle in two layers
               • The opposite orientation to that found in the GI tract
             • Contains transitional epithelium
     • Blood vessels and ureters enter and exit the kidney
   • multi-lobular organ
     • Renal pyramids
       • functional lobes
       • triangular sections of the medulla
         • apex pointing into the center of the kidney
           • Collects urine @ each apex
             • urine flows into minor calyx
               • then major calyx
       • each is separated from its neighbouring renal pyramids by renal columns
       • uriniferous tubules
         • Transverse between
         • functional units of the kidneys
         • Nephrons
           • cortical nephrons
           • juxtamedullary nephrons
         • Collecting Tubules
           • drains urine into the renal pelvis and then exits by the ureter
   • Main Functions
     • Production of glomerular filtrate from the blood
     • Modification of the filtrate to produce urine

2. Bladder

3. Production of urine allows the body to maintain various homeostatic functions

   • regulates plasma volume and blood pressure by regulating urine volume
     • (plasma volume and urinary volume are inversely related)