1. Principles of Biology BIOL 100C: Introductory Biology III The Excretory System Dr. P. Narguizian Fall 2012

2. Education-Portal: Online Video Excretory System http://education-portal.com/academy/lesson/excretory- system.htmlhttp://education-portal.com/academy/lesson/excretory- system.html

3. OSMOREGULATION AND EXCRETION Copyright © 2009 Pearson Education, Inc.  Osmoconformers –Have the same internal solute concentration as seawater –Many marine invertebrates are osmoconformers Animals balance the gain and loss of water and solutes through osmoregulation

4.  Osmoregulators control their solute concentrations  Freshwater fishes –Gain water by osmosis –Excrete excess water –Pump salt across their gills Copyright © 2009 Pearson Education, Inc. Animals balance the gain and loss of water and solutes through osmoregulation

5. Osmotic water gain through gills and other parts of body surface Uptake of salt by gills Uptake of some ions in food Excretion of large amounts of water in dilute urine from kidneys

6.  Saltwater fish –Lose water by osmosis –Drink seawater –Pump out excess salt Copyright © 2009 Pearson Education, Inc. Animals balance the gain and loss of water and solutes through osmoregulation

7. Osmotic water loss through gills and other parts of body surface Excretion of salt from gills Gain of water and salt from food and by drinking seawater Excretion of excess ions and small amounts of water in scanty urine from kidneys

8.  Land animals –Gain water by drinking and eating –Lose water by evaporation and waste disposal –Conserve water using –Kidneys –Behavior adaptations –Waterproof skin Copyright © 2009 Pearson Education, Inc. Animals balance the gain and loss of water and solutes through osmoregulation

9. EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes have evolved in animals  Nitrogenous wastes are toxic breakdown products of protein  Animals dispose of nitrogenous wastes in different ways Copyright © 2009 Pearson Education, Inc.

10.  Ammonia (NH 3 ) –Poisonous –Soluble in water –Easily disposed of by aquatic animals Copyright © 2009 Pearson Education, Inc. EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes have evolved in animals

11.  Urea –Less toxic –Easier to store –Some land animals save water by excreting uric acid –A virtually dry waste –Urea and uric acid take energy to produce Copyright © 2009 Pearson Education, Inc. EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes have evolved in animals

12. Nitrogenous bases —NH 2 Amino groups Amino acids Uric acid Birds and many other reptiles, insects, land snails Nucleic acids Proteins AmmoniaUrea Mammals, amphibians, sharks, some bony fishes Most aquatic animals, including most fishes

13. The urinary system plays several major roles in homeostasis  The excretory system –Expels wastes –Regulates water balance –Regulates ion balance Copyright © 2009 Pearson Education, Inc.

14.  Nephrons –Functional units of the kidneys –Extract a filtrate from the blood –Refine the filtrate to produce urine  Urine –Ureters drain the kidneys –Stored in the urinary bladder –Expelled through the urethra Copyright © 2009 Pearson Education, Inc. The urinary system plays several major roles in homeostasis

15. Aorta Inferior vena cava Renal artery and vein Urinary bladder Kidney Ureter Urethra

16. Renal pelvis Ureter Renal cortex Renal medulla

17. Renal cortex Bowman’s capsule To renal pelvis Collecting duct Renal artery Renal vein Tubule Renal medulla

18. Bowman’s capsule Arteriole from renal artery Arteriole from glomerulus Glomerulus Distal tubule Proximal tubule Branch of renal vein Capillaries From another nephron Loop of Henle with capillary network Collecting duct 3 1 2

19. Overview: The key processes of the urinary system are filtration, reabsorption, secretion, and excretion  Filtration –Blood pressure forces water and many small solutes into the nephron  Reabsorption –Valuable solutes are reclaimed from the filtrate Copyright © 2009 Pearson Education, Inc.

20.  Secretion –Excess H + and toxins are added to the filtrate  Excretion –The final product, urine, is excreted Copyright © 2009 Pearson Education, Inc. Overview: The key processes of the urinary system are filtration, reabsorption, secretion, and excretion

21. Filtration H 2 O, other small molecules Capillary Nephron tubule Reabsorption Secretion Urine Interstitial fluid Excretion

22.  Reabsorption in the proximal and distal tubules removes –Nutrients –Salt –Water  pH is regulated by –Reabsorption of HCO 3 – –Secretion of H + Blood filtrate is refined to urine through reabsorption and secretion Copyright © 2009 Pearson Education, Inc.

23.  High NaCl concentration in the medulla promotes reabsorption of water  Antidiuretic hormone (ADH) regulates the amount of water excreted by the kidneys Copyright © 2009 Pearson Education, Inc. Blood filtrate is refined to urine through reabsorption and secretion

24. Blood Proximal tubule Some drugs and poisons HCO 3 – Nutrients Medulla Bowman’s capsule Cortex H+H+ NaCl H2OH2O H 2 O NaCl HCO 3 – H + Urea Glucose Amino acids Some drugs Filtrate composition NaCl H2OH2O H2OH2O H2OH2O HCO 3 – H+H+ K+K+ Distal tubule 1 2 3 Reabsorption Secretion Filtrate movement Loop of Henle Collecting duct Urea Urine (to renal pelvis)

25. Freshwater Fish Land Animal Saltwater Fish Osmosis Gain water Lose water Excretion Pump in Salt Drinking Osmosis Excrete, pump out Drinking, eating Evaporation, urinary system

26. Urea

27. Bladder Ureter Kidney

28. (a)(b) (c) (d) (e) (f) (g) (h) (i) water and solutes endotherm involves processes of human kidney Homeostasis animal may be maintains balance of both done by requirements depend on mechanisms mostly mechanisms include heat production, insulation, countercurrent heat exchange may be ocean, fresh water, land reproduction (where embryo develops) depends on nitrogenous wastes involves removal of form may be

29. Bowman’s capsule To renal vein From renal artery (a)(b) Loop of Henle Glomerulus Tubule Capillaries Collecting duct (d) (c)

30. 1. Compare the osmoregulatory problems of freshwater fish, saltwater fish, and terrestrial animals. 2. Compare the three ways that animals eliminate nitrogenous wastes. 3. Describe the structure of the human kidney. 4. Explain how the kidney promotes homeostasis. 5.Describe four major processes that produce urine. 6.Describe the key events in the conversion of filtrate into urine. You should now be able to Copyright © 2009 Pearson Education, Inc.