1. © 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey Chapter 25 Control of Body Temperature and Water Balance

2.  During cold winters, bears are often dormant.  Physiological processes aid homeostasis, keeping the body temperature about 5ºC below normal. –Body fat and dense fur provide insulation. –Blood flow to extremities is reduced. –Nitrogen-containing wastes are metabolized differently. Introduction © 2012 Pearson Education, Inc.

3.  Homeostasis is the maintenance of steady internal conditions despite fluctuations in the external environment.  Examples of homeostasis include –thermoregulation—the maintenance of internal temperature within narrow limits, –osmoregulation—the control of the gain and loss of water and solutes, and –excretion—the disposal of nitrogen-containing wastes. Introduction © 2012 Pearson Education, Inc.

4. Figure 25.0_1 Chapter 25: Big Ideas Thermoregulation Osmoregulation and Excretion

5. Figure 25.0_2

6. THERMOREGULATION © 2012 Pearson Education, Inc.

7.  Thermoregulation is –the process by which animals maintain an internal temperature within a tolerable range and –a form of homeostasis. 25.1 An animal’s regulation of body temperature helps maintain homeostasis © 2012 Pearson Education, Inc.

8.  Ectothermic animals –gain most of their heat from external sources and –include many fish, most amphibians, lizards, and most invertebrates.  Endothermic animals –derive body heat mainly from their metabolism and –include birds, mammals, a few reptiles and fish, and many insects. 25.1 An animal’s regulation of body temperature helps maintain homeostasis © 2012 Pearson Education, Inc.

9.  Heat exchange with the environment may occur by –conduction—the transfer of heat by direct contact, –convection—the transfer of heat by movement of air or liquid past a surface, –radiation—the emission of electromagnetic waves, or –evaporation—the loss of heat from the surface of a liquid that is losing some of its molecules as a gas. 25.2 Heat is gained or lost in four ways © 2012 Pearson Education, Inc.

10. Figure 25.2 Evaporation Conduction Radiation Convection

11. 25.3 Thermoregulation involves adaptations that balance heat gain and loss  Five general categories of adaptations help animals thermoregulate. © 2012 Pearson Education, Inc.

12.  Increased metabolic heat production occurs when –hormonal changes boost the metabolic rate in birds and mammals, –birds and mammals shiver, –organisms increase their physical activity, and –honeybees cluster and shiver. 25.3 Thermoregulation involves adaptations that balance heat gain and loss © 2012 Pearson Education, Inc.

13. Figure 25.3_UN01

14.  Insulation is provided by –hair, –feathers, and –fat layers. 25.3 Thermoregulation involves adaptations that balance heat gain and loss © 2012 Pearson Education, Inc.

15.  Circulatory adaptations include –increased or decreased blood flow to skin and –countercurrent heat exchange, with warm and cold blood flowing in opposite directions. 25.3 Thermoregulation involves adaptations that balance heat gain and loss © 2012 Pearson Education, Inc.

16. Figure 25.3_1

17. Figure 25.3_2 Blood from body core in artery Blood returning to body core in vein Blood from body core in artery Blood returning to body core in vein 35  30  20  10  33  C 27  18  99

18.  Evaporative cooling may involve –sweating, –panting, or –spreading saliva on body surfaces. 25.3 Thermoregulation involves adaptations that balance heat gain and loss © 2012 Pearson Education, Inc.

19.  Behavioral responses –are used by endotherms and ectotherms and –include –moving to the sun or shade, –migrating, and –bathing. 25.3 Thermoregulation involves adaptations that balance heat gain and loss © 2012 Pearson Education, Inc.

20. OSMOREGULATION AND EXCRETION © 2012 Pearson Education, Inc.

21.  Osmoregulation is the homeostatic control of the uptake and loss of water and solutes such as salt and other ions.  Osmosis is one process whereby animals regulate their uptake and loss of fluids. 25.4 Animals balance the level of water and solutes through osmoregulation © 2012 Pearson Education, Inc.

22. 25.4 Animals balance the level of water and solutes through osmoregulation  Osmoconformers –have body fluids with a solute concentration equal to that of seawater, –face no substantial challenges in water balance, and –include many marine invertebrates. © 2012 Pearson Education, Inc.

23. 25.4 Animals balance the level of water and solutes through osmoregulation  Osmoregulators –have body fluids whose solute concentrations differ from that of their environment, –must actively regulate water movement, and –include –many land animals, –freshwater animals such as trout, and –marine vertebrates such as sharks. © 2012 Pearson Education, Inc.

24. 25.4 Animals balance the level of water and solutes through osmoregulation  Freshwater fish –gain water by osmosis (mainly through gills), –lose salt by diffusion to the more dilute environment, –take in salt through their gills and in food, and –excrete excess water in dilute urine. © 2012 Pearson Education, Inc.

25. Figure 25.4_1 Fresh water Excretion of large amounts of water in dilute urine from kidneys Uptake of salt ions by gills Uptake of some ions in food Osmotic water gain through gills and other parts of body surface

26.  Saltwater fish –lose water by osmosis from the gills and body surface, –drink seawater, and –use their gills and kidneys to excrete excess salt. 25.4 Animals balance the level of water and solutes through osmoregulation © 2012 Pearson Education, Inc.

27. Figure 25.4_2 Gain of water and salt ions from food and by intake of seawater Osmotic water loss through gills and other parts of body surface Salt water Excretion of excess ions and small amounts of water in concentrated urine from kidneys Excretion of salt from gills

28.  Land animals –face the risk of dehydration, –lose water by evaporation and waste disposal, –gain water by drinking and eating, and –conserve water by –reproductive adaptations, –behavior adaptations, –waterproof skin, and –efficient kidneys. 25.4 Animals balance the level of water and solutes through osmoregulation © 2012 Pearson Education, Inc.

29. 25.5 EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes has evolved in animals  Metabolism produces toxic by-products.  Nitrogenous wastes are toxic breakdown products of proteins and nucleic acids.  Animals dispose of nitrogenous wastes in different ways. © 2012 Pearson Education, Inc.

30.  Ammonia (NH 3 ) is –poisonous, –too toxic to be stored in the body, –soluble in water, and –easily disposed of by aquatic animals. 25.5 EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes has evolved in animals © 2012 Pearson Education, Inc.

31.  Urea is –produced in the vertebrate liver by combining ammonia and carbon dioxide, –less toxic, –easier to store, and –highly soluble in water. 25.5 EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes has evolved in animals © 2012 Pearson Education, Inc.

32.  Uric acid is –excreted by some land animals (insects, land snails, and many reptiles), –relatively nontoxic, –largely insoluble in water, –excreted as a semisolid paste, conserving water, but –more energy expensive to produce. 25.5 EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes has evolved in animals © 2012 Pearson Education, Inc.

33. Figure 25.5 Proteins Ammonia Nitrogenous bases NH 2 (amino groups) Nucleic acids Urea Uric acid Mammals, most amphibians, sharks, some bony fishes Birds and many other reptiles, insects, land snails Most aquatic animals, including most bony fishes Amino acids

34. 25.6 The urinary system plays several major roles in homeostasis  The urinary system –forms and excretes urine and –regulates water and solutes in body fluids.  In humans, the kidneys are the main processing centers of the urinary system. © 2012 Pearson Education, Inc.

35.  Nephrons –are the functional units of the kidneys, –extract a fluid filtrate from the blood, and –refine the filtrate to produce urine.  Urine is –drained from the kidneys by ureters, –stored in the urinary bladder, and –expelled through the urethra. 25.6 The urinary system plays several major roles in homeostasis © 2012 Pearson Education, Inc. Animation: Nephron Introduction

36. Figure 25.6 Aorta Kidney The urinary system Inferior vena cava Renal artery (red) and vein (blue) Ureter Urethra Urinary bladder Renal cortex Renal medulla Renal pelvis Ureter The kidney Proximal tubule Bowman’s capsule Tubule Collecting duct To renal pelvis Branch of renal artery Branch of renal vein Renal cortex Renal medulla Capillaries Glomerulus Distal tubule From another nephron Bowman’s capsule Arteriole from renal artery Arteriole from glomerulus Branch of renal vein Loop of Henle with capillary network Detailed structure of a nephron 1 3 2 Orientation of a nephron within the kidney Collecting duct

37. Figure 25.6_1 Aorta Kidney The urinary system Inferior vena cava Renal artery (red) and vein (blue) Ureter Urethra Urinary bladder

38. Figure 25.6_2 Renal cortex Renal medulla Ureter Renal pelvis The kidney

39. Figure 25.6_3 Bowman’s capsule Tubule Collecting duct To renal pelvis Branch of renal artery Branch of renal vein Renal cortex Orientation of a nephron within the kidney Renal medulla

40. Figure 25.6_4 Proximal tubule Glomerulus Distal tubule Collecting Duct From another nephron Bowman’s capsule Arteriole from renal artery Arteriole from glomerulus Branch of renal vein Loop of Henle with capillary network Detailed structure of a nephron Capillaries 1 3 2

41. 25.7 Overview: The key processes of the urinary system are filtration, reabsorption, secretion, and excretion  Filtration –Blood pressure forces water and many small molecules through a capillary wall into the start of the kidney tubule.  Reabsorption –refines the filtrate, –reclaims valuable solutes (such as glucose, salt, and amino acids) from the filtrate, and –returns these to the blood. © 2012 Pearson Education, Inc.

42. Figure 25.7 Reabsorption SecretionExcretion Urine To renal vein Filtration Nephron tubule Capillary Interstitial fluid H 2 O, other small molecules Bowman’s capsule From renal artery

43. Figure 25.7_1 Filtration Nephron tubule Capillary Interstitial fluid H 2 O, other small molecules Bowman’s capsule From renal artery

44. Figure 25.7_2 ReabsorptionSecretion Excretion Urine To renal vein Capillary Nephron tubule

45.  Substances in the blood are transported into the filtrate by the process of secretion.  By excretion the final product, urine, is excreted via the ureters, urinary bladder, and urethra. 25.7 Overview: The key processes of the urinary system are filtration, reabsorption, secretion, and excretion © 2012 Pearson Education, Inc.

46. Figure 25.7 Reabsorption SecretionExcretion Urine To renal vein Filtration Nephron tubule Capillary Interstitial fluid H 2 O, other small molecules Bowman’s capsule From renal artery

47.  Reabsorption in the proximal and distal tubules removes –nutrients, –salt, and –water.  pH is regulated by –reabsorption of HCO 3 – and –secretion of H +. 25.8 Blood filtrate is refined to urine through reabsorption and secretion © 2012 Pearson Education, Inc.

48.  High NaCl concentration in the medulla promotes reabsorption of water. 25.8 Blood filtrate is refined to urine through reabsorption and secretion © 2012 Pearson Education, Inc. Animation: Bowman’s Capsule and Proximal Tubule Animation: Collecting Duct Animation: Effect of ADH Animation: Loop of Henle and Distal Tubule

49. Figure 25.8 Bowman’s capsule Blood Nutrients H 2 O NaCl Proximal tubule Some drugs and poisons Cortex Medulla Interstitial fluid Loop of Henle H2OH2O Filtrate composition Reabsorption Filtrate movement Secretion Distal tubule 1 2 NaCl Urea H2OH2O 3 KK HH Collecting duct Urine (to renal pelvis) H2OH2O NaCl HCO 3  H 2 O Salts (NaCl and others) HCO 3  H  Urea Glucose Amino acids Some drugs HCO 3  HH

50. Figure 25.8_1 Blood Filtrate composition Reabsorption Filtrate movement Secretion Bowman’s capsule Nutrients H 2 O NaCl HCO 3  Proximal tubule Some drugs and poisons Cortex Medulla HH H 2 O Salts (NaCl and others) HCO 3  H  Urea Glucose Amino acids Some drugs

51. Figure 25.8_2 Reabsorption Filtrate movement Secretion Nutrients NaCl HCO 3  Some drugs and poisons Cortex Medulla Proximal tubule Interstitial fluid Loop of Henle H2OH2O NaCl Urea H2OH2O Collecting duct Urine (to renal pelvis) Distal tubule H2OH2O NaCl HCO 3  1 3 2 H2OH2O HH H K  

52.  Antidiuretic hormone (ADH) regulates the amount of water excreted by the kidneys by –signaling nephrons to reabsorb water from the filtrate, returning it to the blood, and –decreasing the amount of water excreted.  Diuretics –inhibit the release of ADH and –include alcohol and caffeine. 25.9 Hormones regulate the urinary system © 2012 Pearson Education, Inc.

53.  Kidney failure can result from –hypertension, –diabetes, and –prolonged use of common drugs, including alcohol.  A dialysis machine –removes wastes from the blood and –maintains its solute concentration. 25.10 CONNECTION: Kidney dialysis can be lifesaving © 2012 Pearson Education, Inc.

54. Figure 25.9 Line from artery to apparatus Pump Tubing made of a selectively permeable membrane Dialyzing solution Fresh dialyzing solution Used dialyzing solution (with urea and excess ions) Line from apparatus to vein

55. Figure 25.9_1 Line from artery to apparatus Pump Tubing made of a selectively permeable membrane Dialyzing solution Fresh dialyzing solution Used dialyzing solution (with urea and excess ions) Line from apparatus to vein

56. Figure 25.9_2

57. 1.Explain how bear physiology adjusts during dormancy. 2.Describe four ways that heat is gained or lost by an animal. 3.Describe five categories of adaptations that help animals thermoregulate. 4.Compare the osmoregulatory problems of freshwater fish, saltwater fish, and terrestrial animals. You should now be able to © 2012 Pearson Education, Inc.

58. 5.Compare the three ways that animals eliminate nitrogenous wastes. 6.Describe the structure and functions of the human kidney. 7.Explain how the kidney promotes homeostasis. 8.Describe four major processes that produce urine. 9.Describe the key events in the conversion of filtrate into urine. 10.Explain why a dialysis machine is necessary and how it works. You should now be able to © 2012 Pearson Education, Inc.

59. Figure 25.4_UN01

60. Figure 25.UN01 35  33  C 27  30  20  10  99 18 

61. Figure 25.UN02 Freshwater Fish Osmosis Gain Water Drinking, eating Saltwater Fish Land Animal Evaporation, urinary system Drinking Osmosis Excretion Pump in Excrete, pump out Lose Water Salt

62. Figure 25.UN03 Urea

63. Figure 25.UN04 Kidney Ureter Bladder

64. Figure 25.UN05 Homeostasis involves processes of (a) (b) (d) animal may be maintains balance of water and solutes human kidney both done by (c) involves removal of nitrogenous wastes (e) (f) (g) form may be depends on reproduction (where embryo develops) (i) may be endotherm mechanisms include requirements depend on mechanisms mostly (h) heat production, insulation, countercurrent heat exchange ocean, fresh water, land

65. Figure 25.UN06 (a) (b) Bowman’s capsule From renal artery To renal vein Glomerulus Tubule Capillaries Loop of Henle (d) (c) Collecting duct