1. The Urinary System Glen Hookey Eric Kolker Justin Loeb Michael Ross Uston—Period 5

2. Overview

3. Animals and Waste Filter body fluid for toxins and unnecessary substances Kidneys (bp, activation of vitamin D, erythropoietin, wastes) Nitrogenous waste

4. Transport Epithelium Manage solute levels Line many channels inside the body Comprised of special epithelial cells Can move solutes against gradient

5. Nitrogenous Wastes Three types: Ammonia, Urea, Uric Acid Ammonia –Highly toxic, diluted with large supplies of water Urea –Low toxicity, energy cost (used by mammals) Uric Acid –Low toxicity, water insoluble, excreted as a paste

6. Excretory Processes Filtration –One layer of transport epithelium (large molecules removed); filtrate Reabsorption –Active transport (glucose, amino acids, etc.) Secretion –Materials added to excretory tubule Excretion –Expelled as urine

7. Filtrate/Urine Pathway

8. Kidney Filters substances form blood Adjusts filtrate’s composition Returns most substances to blood

10. Nephron Functional unit Packed tubules Surrounded by capillaries Filters blood

11. Bowman’s Capsule Start of Nephron Glomerulus Filtration into lumen: –Water, salts bicarbonate, hydrogen ions, urea, glucose, amino acids

12. Proximal Tubule pH maintained Reabsorption Reabsorbs Na+  osmosis

13. Loop of Henle Descending –Water Ascending –Thin & Thick –Passive & Active

14. Distal Tubule pH regulation Sodium, calcium, potassium

15. Collecting Duct Subject to hormonal controls Diseases Concentration of filtrate

16. Urine Composition Excess water and solutes Ions Urea Neurotransmitters Histamine Drugs/toxins

17. Osmoregulation Solute gradient Bends in nephron Membrane selective permeability Diffusion Active transport Salt

18. Solute Gradient Membrane selective permeability Interstitial fluid Filtrate Active transport Diffusion

19. Nephron Overview Proximal Tubule Descending Loop of the henle Ascending Loop of the henle Distal Tubule Collecting duct

20. Gradient Overview

21. Gradient #1: Proximal tubule Blood –~300 mosm/L Interstitial fluid: –~300 mosm/L Filtrate: –~300 mosm/L –In: Hydrogen ions Ammonia –Out: Bicarbonate Salt Water Nutrients Potassium ions In cortex Volume decreased Osmolarity stays constant

22. Gradient #2: Descending Loop of the Henle –Interstitial fluid 300 - 1200 mosm/L –Filtrate 300 - 1200 mosm/L In –N/A Out –Water –Membrane permeable only to water –Salt concentration increases –Water diffuses out

23. Gradient #3: Ascending Loop of the Henle Ascending loop –Interstitial fluid 1200 - 300 mosm/L –Filtrate 1200 - 200 mosm/L In –N/A Out –Salt –Membrane permeable only to Salt –Salt concentration decreases –Filtrate osmolarity lowered to increase osmolarity of interstitial fluid

24. Gradient #4: Distal tubule Interstitial fluid –300 mosm/L Filtrate –100 mosm/L –In Potassium ions Hydrogen ions –Out Salt Water Bicarbonate Filtrate at lowest osmolarity Key role in determination of pH of urine

25. Gradient #5: Collection duct Interstitial fluid –300 - 1200 mosm/L Filtrate –300 - 1200 mosm/L –In N/A –Out Salt Urea Water Final stage Controls final salt output Low salt Water diffuses Concentrated filtrate

27. Regulation #1: ADH Antidiuretic hormone Hormone Activated by hypothalamus at high blood osmolarity Decreases water loss –More permeability to water

28. Regulation #2: RAAS Renin-angiotensin- aldosterone system Angiotensin II Activated at low blood pressure/volume Decreases water loss –Constricts capillaries –More reabsorption of salt

29. Regulation #3: ANF Atrial natriuretic factor Opposite of ADH and RAAS –Triggered by high blood pressure/volume –Inhibits NaCl absorption –Increased water loss through urine Disables ADH

31. Ureter Lining of ureter Smooth-muscle cells contractions Ureter crosses bladder wall Ureter in Micturition

32. Urinary Bladder Storage organ Bladder in micturition Brain cells Structure

33. Urethra Function and location Cells of Urethra External Meatus

34. Abnormalities of the Renal System Acute Chronic Congenital

35. Congenital Problems Horseshoe kidneys –Functions as one kidney Has to be cautious of rigorous activity

36. Acute Problems Usually reversible Examples: stones, infections, tumors, inflammation, acute renal failure Detected by urinalysis or by pain and fever

37. Urinary Tract Infection (UTI) Occurs anywhere along the urinary tract (kidneys, bladder) Women more prone than men; shorter urethra Pain and fever Treated with antibiotics

40. Tumors and Stones Most tumors in kidneys and bladder are malignant Smokers are prone to bladder tumors Stones- intensely painful Can be passed but some require surgery or ultrasound

43. Trauma Kidneys damaged by physical trauma People with one kidney have to avoid potentially dangerous activities Blood in urine

44. Chronic Kidney Failure Dialysis (3 days a week; 4 hours) –Cleans blood Only cure is transplantation