1. Urinary System http://www.youtube.com/watch?NR=1&v=_NO8n48AKJY&f eature=endscreenhttp://www.youtube.com/watch?NR=1&v=_NO8n48AKJY&f eature=endscreen start at 36 seconds

2. Major Players: Kidneys Help maintain homeostasis: 1.Make hormones & enzymes 2. Excrete wastes – Filter out gallons of fluid from the blood – Wastes and extra ions are put in urine 3. Maintain purity/regulate concentrations of fluids – Needed substances are returned to blood – Maintain balance of salt & water and acids & bases

4. Major Players: Ureters 2 tubes (~30 cm long X ½ cm wide) Drain urine from kidneys  bladder Smooth muscle moves urine via peristalsis Kidney stones cause PAIN when they get here!

5. Collapsible muscular sac (2-3 in. when empty, holds 1 pint of urine) Made of transitional epithelium ***Males the prostate gland surrounds neck where bladder empties Major Players: Bladder

6. Major Players: Urethra Tube carries urine from bladder  outside Internal urethra sphincter- involuntary (smooth muscle), prevents urine from leaking out External urethra sphincter- voluntary (skeletal muscle)

7. Urination Bladder collects urine until ~200 ml of urine has entered activates stretch receptors bladder does reflex contractions urine passes through involuntary internal urethral sphincter to top of urethra person feels urge to go Micturition- act of emptying the bladder

8. When you get the urge to go… Incontinence - lack voluntary control of the external sphincter – toddlers  can’t control sphincter – sleeping children  aren’t awakened by the stimulus Keep external sphincter closed causing bladder contractions to stop; When 200-300 ml more accumulates urge to pee returns! Relax external urethral sphincter and urinate