1. THE URINARY SYSTEM Chapter 25

2. Introduction Urology is the branch of medicine that deals with the urinary system. There are three functions of the urinary system: Regulates volume, composition, and pH of body fluids. Excretes metabolic wastes. Regulates blood pressure, RBC production, synthesizes calcitriol, and performs gluconeogenesis.

3. Basic Gross Anatomy Two kidneys Two ureters Urinary bladder Urethra

4. External Anatomy of the Kidneys Within the muscular wall of the back between T12-L3. Renal hilus Connective tissue layers: Renal capsule Adipose capsule Renal fascia

5. Internal Anatomy of the Kidneys Renal Cortex Renal Medulla Renal pyramids Renal papillae Renal columns Renal Pelvis With major calyces and minor calyces

6. Blood Supply of the Kidney

7. Nephron Anatomy Renal Corpuscle Glomerulus Bowman’s capsule Renal Tubules Proximal convoluted tubule (PCT) Loop of Henle Distal convoluted tubule (DCT)

8. Renal Corpuscle

9. Filtration Membrane

10. Podocytes

11. Filtration Membrane

12. Renal Tubules

14. Types of Nephrons Cortical Nephrons Juxtamedullary nephrons

15. Renal Physiology Occurs in Three Steps: Non-selective filtration Tubular reabsorption Tubular secretion

16. NON-SELECTIVE FILTRATION Step 1

17. Renal Physiology

18. Non-Selective Filtration

19. Glomerular Filtration Rate

20. REABSORPTION Step 2A

21. Tubular Reabsorption

24. Tubular Reabsorption at the PCT Glucose, lactate, amino acids and vitamins – 100% Bicarbonate ions – 90% Water and sodium ions – 65% Potassium ions – 55% Chloride ions – 50% Others are hormonally controlled

25. Tubular Reabsorption

27. Countercurrent Mechanism

28. Tubular Reabsorption

29. Tubular Reabsorption at the Loop Chloride – 35% Potassium – 30% Sodium ions – 25% Water – 10%

30. Tubular Reabsorption

32. Tubular Reabsorption at the DCT Water – 25% Chloride – 10% Sodium ions – 10%

33. Tubular Reabsorption

35. SECRETION Step 2B

36. Tubular Secretion

37. Regulation by Hormones Antidiuretic hormone (ADH) Aldosterone Atrial natriuretic peptide (ANP) Renin and Angiotensin II

38. Urine Formation Urine composition 90-95% water Solutes constitute the other 5% Metabolic wastes (urea, uric acid, and creatinine) Ions (Na +, K +, PO 4 3-, SO 4 2-, Ca 2+, Mg 2+ ) Toxins and pigments (urochrome) Hormones Urine characteristics Yellow in color Slightly aromatic or ammonia odor pH slightly acidic (can vary from 4.5 to 8.0) Specific gravity 1.001 to 1.035

39. Abnormal Urine Constituents

40. Ureters

41. Urinary Bladder and Urethra

42. Micturition

44. Homeostatic Imbalances Ptosis Hydronephrosis Pyelitis Pyelonephritis Anuria & Hyperuria Hypospadias Diabetes insipidus Cystocele Renal calculi Urethritis Cystitis Incontinence Urinary retention Horseshoe kidney Polycystic kidney Renal infarct