1. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dee Unglaub Silverthorn, Ph.D. H UMAN P HYSIOLOGY PowerPoint ® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 19 The Kidneys

2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Excretory System: Anatomy Review Figure 19-1: Anatomy Summary: The Urinary System Kidney Cortex Medulla Pelvis Nephrons Ureter Bladder Urethra

3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 3 processes of the nephron are: filtration, reabsorption and secretion. Figure 19-2: Filtration, reabsorption, secretion, and excretion

4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Kidney Functions: Overview Figure 19-3: The excretion of a substance depends on the amount that was filtered, reabsorbed, and secreted

5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings FILTRATION Glomerulus + Bowman's Capsule = Renal corpuscle Figure 19-4: Structure of the renal corpuscle 3 barriers to filtration: 1.Glomerular capillary endothelium 2.Basal lamina (acellular; collagen and glycoproteins) 3. Epithelium of Bowman’s capsule (podocytes) Fenestrated capillaries Filtration slits

6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Have actin and can contract to alter filtration.

7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Glomerular Flow Rate (GFR): average GFR is 125 mls/min! Figure 19-6: Filtration pressure in the renal corpuscle Glomerular Capillary Hydrostatic pressure out (55 mmHg) Colloid osmotic pressure in ( 30 mmHg) Bowman’s Capsule pressure “Back” hydrostatic pressure in (15 mmHg) Net Filtration 10 mmHg GFR  180L/day (about 1% is excreted) Do you urinate 180L/day???

8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Glomerular Flow Rate (GFR) Figure 19-5: The filtration fraction urine

9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 19-9: The juxtaglomerular apparatus Regulation of GFR: Tubuloglomerular FB Macula densa + juxtaglomerular cells = Juxtaglomerular apparatus

10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings

11. Reabsorption: Can be ACTIVE or PASSIVE Passive diffusion in: molecules travel down their concentration/electrochemical gradients. Active Transport : molecules pushed against their gradients. Must use primary or secondary active transport. Reabsorption of: Sodium Urea Glucose

12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Sodium Reabsorption: Primary Active Transport Figure 19-11: Sodium reabsorption in the proximal tubule Proximal tubule

13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Reabsorption: Secondary Active Transport of glucose Figure 19-12: Sodium-linked glucose reabsorption in the proximal tubule Na + linked 2 0 transport A lot of “stuff” follows sodium out of the tubule lumen. Symports make this happen Glucose Ions Amino acids Proximal tubule, key site

14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Reabsorption: Passive Transport of Urea IN the proximal tubule 1. sodium and other solutes are reabsorbed. 2. Water follows. When water leaves, no urea has left yet. You have smaller volume with same amount of urea. Urea concentration is higher. 3. NOW urea will be reabsorbed passively down its concentration gradient.

15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Reabsorption: The concept of saturation Saturation – refers to the maximum rate of transport (of glucose, or something) that occurs when all available carriers are occupied with substrate.

16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Saturation; a closer look Glucose on a carrier Blood nephron Glucose Glucose carrier

17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Reabsorption: Receptors can Limit Figure 19-15: Glucose handling by the nephron