1. Kidney Objective: Nephron Anatomy and Function

2. Nephron Anatomy consists of Renal corpuscle Renal tubule

3. Renal corpuscle 1.Glomerulus 2.Bowman’s capsule Bowman’s capsule Glomerulus

4. Renal tubule 1.Proximal convoluted tubule (PCT) Proximal Convoluted (twisted) tubule

5. Renal tubule 2.Loop of Henle Loop of Henle

6. Renal tubule 3.Distal convoluted tubule (DCT) Distal Convoluted tubule

7. Collecting tubule Collecting tubule

8. Nephron Function Three Processes - 1. Filtration (blood to capsule) 2. Reabsorption (return to blood) 3.Secretion (added to urine)

9. 1. Filtration In Renal corpuscle  Glomerulus → Bowman’s capsule  Filters from blood 180 liters/day (45 gallons) [barrel is 55 gallons]

10. Filtration (cont)  To Bowman’s capsule:  Water  Amino acids  Glucose  Urea  Na, K, Cl  Hormones  Vitamins

11. Filtration (cont)  What doesn’t cross  Blood cells  Medium to Large proteins

12. 2. Reabsorption Peritubular capillaries → PCT, DCT, & Loop of Henle Most of water Glucose Na K Cl Amino acids Vit & Hormones PCT Loop of Henle

13. 3. Secretion Peritubular capillaries → PCT and DCT Urea H+ (pH) Toxins –Drugs –Antibiotics

14. Secretion (cont) Peritubular capillaries → Collecting tubules

15. Daily Totals  Filtration ~ 180 liters filtered out/day  Reabsorption ~ 179 liters returned to the blood/day  ~ 1 liter excreted as urine/day (0.78 mL/min)

16. Ureter  Connects kidney to bladder  10-12 inches long  Made of smooth muscle  Uses peristalsis  Rhythmic contractions of muscle

17. Bladder  hollow, muscular  Capacity:  700-800 mL (average)  Made of:  Transitional epithelium  Stretchy!  Smooth muscle

18. Sphincters  Internal  Smooth muscle  Autonomic (Automatic)  Controlled by spinal cord

19. Sphincters  External  Skeletal muscle  Cerebral control  Micturition  Expel urine from bladder