Osmoregulation and Disposal of Metabolic Wastes

1. Osmoregulation and Disposal of Metabolic Wastes Chapter 47

2. Learning Objective 1 • How do the processes of osmoregulationand excretioncontribute to fluid and electrolyte homeostasis?

3. Fluid-Electrolyte Homeostasis • Osmoregulation • active regulation of osmotic pressure of body fluids • maintains fluid and electrolyte homeostasis • Excretion • process of ridding body of metabolic wastes

4. Learning Objective 2 • Contrast the benefits and costs of excreting ammonia, uric acid, or urea

5. Nitrogenous Wastes • Ammonia (toxic) • excreted mainly by aquatic animals • Urea (less toxic) • synthesis requires energy • excretion requires water • Uric acid (less toxic) • excreted as semisolid paste (conserves water)

6. Nitrogenous Wastes

7. Amino acids Nucleic acids Deamination Keto acids Purines Ammonia Urea cycle 15 steps Ammonia Urea Uric acid More energy needed to produce More water needed to excrete Fig. 47-1, p. 1013

8. Nucleic acids Amino acids Deamination Keto acids Purines Ammonia Urea cycle 15 steps Ammonia Urea Uric acid More energy needed to produce More water needed to excrete Stepped Art Fig. 47-1, p. 1013

9. Learning Objective 3 • Compare osmoconformers and osmoregulators

10. Osmoconformers • Most marine invertebrates • Salt concentration of body fluids varies with changes in sea water

11. Osmoregulators • Some marine invertebrates • especially in coastal habitats • Maintain optimal salt concentration despite changes in salinity of surroundings

12. KEY CONCEPTS • Osmoregulation is the process by which organisms control the concentration of water and salt in the body so that their body fluids do not become too dilute or too concentrated

13. Learning Objective 4 • Describe protonephridia, metanephridia, and Malpighian tubules • Compare their functions

14. Nephridial Organs • Help maintain homeostasis • by regulating concentration of body fluids • osmoregulation • excretion of metabolic wastes

15. Protonephridia • Tubules with no internal openings • in flatworms and nemerteans • Interstitial fluid enters blind ends • flame cells (cells with brushes of cilia) • Cilia propel fluid through tubules • Excess fluid exits through nephridiopores

16. Protonephridia

17. Flame cells Protonephridial network Nephridiopores Excretory tubule Flatworm Fig. 47-2ab, p. 1014

18. Nucleus Cytoplasm Cilia (“flame”) Movement of interstitial fluid Excretory tubule Fig. 47-2c, p. 1014

19. Metanephridia • Tubules open at both ends • in most annelids and mollusks • Fluid from coelom moves through tubule • needed materials reabsorbed by capillaries • Urine exits body through nephridiopores • contains wastes

20. Metanephridia

21. Tubule Anterior Posterior Gut Funnel Capillary network Septum Nephridiopore Fig. 47-3, p. 1014

22. Malpighian Tubules 1 • Extensions of insect gut wall • blind ends lie in hemocoel • Tubule cells actively transport uric acid from hemolymph into tubule • water follows by diffusion • Contents of tubule pass into gut

23. Malpighian Tubules 2 • Water and some solutes reabsorbed in rectum • Malpighian tubules effectively conserve water • contribute to success of insects as terrestrial animals

24. Malpighian Tubules

25. Gut Malpighian tubules Waste Rectum Hindgut Midgut Water and needed ions Fig. 47-4, p. 1014

26. KEY CONCEPTS • Excretory systems have evolved that function in both osmoregulation and in disposal of metabolic wastes

27. Learning Objective 5 • Relate the function of the vertebrate kidney to the success of vertebrates in a wide variety of habitats

28. The VertebrateKidney • Excretes nitrogenous wastes • Helps maintain fluid balance by adjusting salt and water content of urine

29. Adaptation to Habitats • Freshwater, marine, terrestrial habitats • different problems for maintaining internal fluid balance, excretion of nitrogenous wastes • Structure and function of vertebrate kidney • adapted to various osmotic challenges of different habitats

30. KEY CONCEPTS • The vertebrate kidney maintains water and electrolyte balance and excretes metabolic wastes

31. Learning Objective 6 • Compare adaptations for osmoregulation in freshwater fishes, marine bony fishes, sharks, marine mammals, and terrestrial vertebrates

32. Freshwater Fishes • Take in water osmotically • excrete large volume of hypotonic urine

33. Loses salt by diffusion Water gain by osmosis Drinks no water Salt uptake by gills Large volume of hypotonic urine Kidney with large glomeruli Fig. 47-5a, p. 1015

34. Marine Bony Fishes • Lose water osmotically • Compensate by drinking sea water and excreting salt through their gills • Produce only a small volume of isotonic urine

35. Gains salts by diffusion Water loss by osmosis Drinks salt water Small volume of isotonic urine Salt excreted through gills Kidney with small or no glomeruli Fig. 47-5b, p. 1015

36. Sharks and Other Marine Cartilaginous Fishes • Retain large amounts of urea • allows them to take in water osmotically through their gills • Excrete large volume of hypotonic urine

37. Water gain by osmosis Salt-excreting gland Salts diffuse in through gills Some salt water swallowed with food Large volume of hypotonic urine Kidney with large glomeruli—reabsorbs urea Fig. 47-5c, p. 1015

38. Marine Mammals • Ingest sea water with their food • produce concentrated urine

39. Terrestrial Vertebrates • Must conserve water • adaptations include efficient kidneys • Endotherms • have a high metabolic rate • produce large volume of nitrogenous wastes

40. LIVER ALL CELLS Hemoglobin breakdown Wastes produced Breakdown of nucleic acids Cellular respiration Deamination of amino acids Uric acid Water Bile pigments Carbon dioxide Wastes Urea Organs of excretion SKIN KIDNEY LUNGS DIGESTIVE SYSTEM Exhaled air containing water vapor and carbon dioxide Excretion Sweat Urine Feces Fig. 47-6b, p. 1016

41. KEY CONCEPTS • Freshwater, marine, and terrestrial animals have different adaptations to meet the challenges of these diverse environments

42. Learning Objective 7 • Describe (or label on a diagram) the organs of the mammalian urinary system • Give the functions of each

43. The Urinary System • Principal excretory system in mammals • Mammalian kidneys produce urine • passes through ureters • to urinary bladder for storage • Urine is released from the body (urination) • through the urethra

44. Human Urinary System

45. Adrenal gland Right kidney Left renal artery Right renal vein Left kidney Inferior vena cava Abdominal aorta Ureteral orifices Right and left ureters Urinary bladder Urethra External urethral orifice Fig. 47-7, p. 1017

46. Kidney Structure 1 • Renal cortex • outer portion of kidney • Renal medulla • inner portion of kidney • contains 8 to 10 renal pyramids • Renal pyramids • tip of each pyramid is a renal papilla

47. Kidney Structure 2 • Urine flows into collecting ducts • which empty through a renal papilla into the renal pelvis (funnel-shaped chamber) • Nephrons • functional units of kidney • each kidney has more than 1 million

48. Internal Kidney Structure

49. Renal pyramids (medulla) Capsule Renal cortex Renal medulla Renal artery Renal vein Renal pelvis Ureter Internal structure of the kidney. Fig. 47-8a, p. 1018

50. Distal convoluted tubule Juxtamedullary nephron Cortical nephron Capsule Proximal convoluted tubule Renal cortex Glomerulus Bowman’s capsule Artery and vein Loop of Henle Renal medulla Collecting duct Papilla Juxtamedullary and cortical nephrons. Fig. 47-8b, p. 1018