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'''Fundamental'Biology' '''''''''''''''BI'1101'''' ''''''''an'interdisciplinary'approach'to'introductory'biology' Anggraini'Barlian,' Iriawa-' Tjandra'Anggraeni' SITH4ITB' 1 Five'Levels'of'Organiza-on' Molecular' Cellular' Organismal' Popula-on' Ecological'System' 2 Learning outcomes After this lecture, you should be able to: 1. Describe four ways that heat is gained or lost by an animal. 2. Describe five categories of adaptations that help animals thermoregulate. 3. Compare the osmoregulatory problems of freshwater fish, saltwater fish, and terrestrial animals. 4. Compare the three ways that animals eliminate nitrogenous wastes. 5. Describe the structure and functions of the human kidney. 6. Explain how the kidney promotes homeostasis. 7. Describe four major processes that produce urine and the key events in the conversion of filtrate into urine. 8. Explain why a dialysis machine is necessary and how it works. 3 CONTROL OF BODY TEMPERATURE AND WATER BALANCE 4 5 Introduction • 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. © 2012 Pearson Education, Inc. 6 • Animals live nearly everywhere on Earth ! The extremely dry, frigid Arctic habitat or perpetual humidity of a tropical rain forest. • These habitats select for very different ways of regulating body temperature, conserving water, and disposing of wastes. • In hot, dry areas, an animal must conserve enough water for cells to function and, produce enough sweat to tolerate the heat. • At another extreme, frigid water surrounds an animal living in an Arctic freshwater lake. An animal in this habitat must continually pump excess water out of its body and conserve salts, all while surviving the cold. 7 Introduction • 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. © 2012 Pearson Education, Inc. 8 Big Ideas Thermoregulation Osmoregulation and Excretion 9 THERMOREGULATION © 2012 Pearson Education, Inc. 10 An animal s regulation of body temperature helps maintain homeostasis Thermoregulation is – the process by which animals maintain an internal temperature within a tolerable range ! requires the ability to balance heat gained from and lost to the environment – a form of homeostasis. " An animal maintain homeostasis by controlling how much heat it produces. When cells generate ATP in aerobic respiration they also produce metabolic heat. The more active the animal, the higher its metabolic rate and the more heat it produces. © 2012 Pearson Education, Inc. 11 An animal s regulation of body temperature helps maintain homeostasis • 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. 12 Heat is gained or lost in four ways • 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. 13 Figure 25.2 Evaporation Radiation Convection Conduction 14 Thermoregulation involves adaptations that balance heat gain and loss Five general categories of adaptations help animals thermoregulate. • 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. © 2012 Pearson Education, Inc. 15 16 Figure 25.3_UN01 17 Thermoregulation involves adaptations that balance heat gain and loss • Insulation is provided by – hair, – feathers, and – fat layers. • Circulatory adaptations include – increased or decreased blood flow to skin and – countercurrent heat exchange, with warm and cold blood flowing in opposite directions. © 2012 Pearson Education, Inc. 18 19 Figure 25.3_2 Blood from body core in artery Blood returning to body core in vein 35° 33°C 30° 27° 20° 18° 10° 9° Blood from body core in artery Blood returning to body core in vein 20 Thermoregulation involves adaptations that balance heat gain and loss • Evaporative cooling may involve – sweating, – panting, or – spreading saliva on body surfaces. • Behavioral responses – are used by endotherms and ectotherms and – include • moving to the sun or shade, • migrating, and • Bathing. © 2012 Pearson Education, Inc. 21 22 OSMOREGULATION AND EXCRETION © 2012 Pearson Education, Inc. 23 Animals balance the level of water and solutes through osmoregulation # 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. © 2012 Pearson Education, Inc. 24 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. 25 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. 26 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. Uptake of some ions in food Osmotic water gain through gills and other parts of body surface Uptake of salt ions by gills Fresh water Excretion of large amounts of water in dilute urine from kidneys 27 25.4 Animals balance the level of water and solutes through osmoregulation • Saltwater fish – lose water by osmosis from the gills and body surface, – drink seawater, and – use their gills and kidneys to excrete excess salt. Gain of water and salt ions from food and by intake of seawater Osmotic water loss through gills and other parts of body surface Excretion of salt from gills Salt water Excretion of excess ions and small amounts of water in concentrated urine from kidneys 28 Animals balance the level of water and solutes through osmoregulation • 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. © 2012 Pearson Education, Inc. 29 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 EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes has evolved in animals • Ammonia (NH3) is – – – – poisonous, too toxic to be stored in the body, soluble in water, and easily disposed of by aquatic animals. © 2012 Pearson Education, Inc. 31 EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes has evolved in animals • Urea is – produced in the vertebrate liver by combining ammonia and carbon dioxide, – less toxic, – easier to store, and – highly soluble in water. © 2012 Pearson Education, Inc. 32 EVOLUTION CONNECTION: A variety of ways to dispose of nitrogenous wastes has evolved in animals • 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. 33 © 2012 Pearson Education, Inc. Proteins Amino acids Nitrogenous bases Nucleic acids NH2 (amino groups) Most aquatic animals, including most bony fishes Mammals, most amphibians, sharks, some bony fishes Birds and many other reptiles, insects, land snails Uric acid Ammonia Urea 34 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 The urinary system plays several major roles in homeostasis • 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. © 2012 Pearson Education, Inc. 36 Figure 25.6 Renal cortex Renal medulla Aorta Inferior vena cava Renal artery (red) and vein (blue) Ureter Kidney Renal pelvis Urinary bladder Urethra The urinary system Bowman s capsule Glomerulus Arteriole from renal artery 1 Ureter Proximal tubule Capillaries 3 Arteriole from glomerulus From another nephron Branch of renal vein 2 Distal tubule Collecting duct Loop of Henle with capillary network Detailed structure of a nephron The kidney Bowman s capsule Tubule Renal cortex Branch of renal artery Branch of renal vein Collecting duct Renal medulla To renal pelvis Orientation of a nephron within the kidney 37 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. 38 Figure 25.7 Bowman s From capsule renal artery Filtration Reabsorption Secretion Excretion Nephron tubule H2O, other small molecules Urine Interstitial fluid To renal vein Capillary 39 Figure 25.7_1 From Bowman s Filtration renal capsule artery Nephron tubule H2O, other small molecules Interstitial fluid Capillary 40 Figure 25.7_2 Reabsorption Secretion Excretion Nephron tubule Urine Capillary To renal vein 41 25.7 Overview: The key processes of the urinary system are filtration, reabsorption, secretion, and excretion • 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. © 2012 Pearson Education, Inc. 42 Blood filtrate is refined to urine through reabsorption and secretion • Reabsorption in the proximal and distal tubules removes – nutrients, – salt, and – water. • pH is regulated by – reabsorption of HCO3– and – secretion of H+. • High NaCl concentration in the medulla promotes reabsorption of water. 43 © 2012 Pearson Education, Inc. Figure 25.8_1 Bowman s capsule Proximal tubule Nutrients H2O NaCl HCO3 Blood Cortex Filtrate composition H 2O Salts (NaCl and others) HCO3H+ Urea Glucose Amino acids Some drugs Some H+ drugs and poisons Medulla Reabsorption Secretion Filtrate movement 44 Figure 25.8_2 Proximal tubule Nutrients H2O NaCl HCO3 Cortex 1 Distal tubule H 2O NaCl HCO3K+ H+ Some H+ drugs and poisons 3 Collecting duct Medulla Interstitial Loop of fluid Henle 2 NaCl NaCl H 2O NaCl Urea H 2O Reabsorption Secretion Filtrate movement Urine (to renal pelvis) 45 Hormones regulate the urinary system • 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. © 2012 Pearson Education, Inc. 46 47 CONNECTION: Kidney dialysis can be lifesaving • 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. © 2012 Pearson Education, Inc. 48 Figure 25.9_1 Line from artery to apparatus Pump Line from apparatus to vein Tubing made of a selectively permeable membrane Dialyzing solution Fresh dialyzing solution Used dialyzing solution (with urea and excess ions) 49 Figure 25.9_2 50