Module 11.1 - Urinary System PDF
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Module 11.1 covers the urinary system and osmoregulation in animals. It discusses the balance of water and solute uptake and loss, and how different animals adapt to various environments. The document also covers concepts like osmosis and osmolarity.
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ODULE 11.1: THE URINARY M SYSTEM - smoregulators: Expend energy to control water O EXCRETION & OSMOREGULATION...
ODULE 11.1: THE URINARY M SYSTEM - smoregulators: Expend energy to control water O EXCRETION & OSMOREGULATION uptake and loss in ahyperosmoticorhypoosmotic environment. (Ex: sockeye salmon) SMOREGULATION O Itisbasedlargelyonbalancingtheuptakeandloss arine Animals M of water and solutes. Most marineinvertebrates are osmoconformers. T he driving force for movement of solutes and any marine vertebrates and some marine M water is a concentration gradient of one or more invertebrates are osmoregulators. solutes across the plasma membrane. Marinebony fishes are hypoosmoticto seawater. hysiological systems of animals operate in a fluid P They balance water loss by drinking large environment. amounts of seawater and eliminating the ingested salts through their gills and kidneys. elative concentrations of water and solutes must R bemaintained within fairly narrow limits. smosis:Processbywhichwaterentersandleaves O cells. smolarity: The solute concentration of a solution, O determines the movement of water across a selectively permeable membrane. Isoosmotic: Water molecules will cross the F reshwater Animals membrane at equal rates in both directions if They constantly take inwaterbyosmosisfromtheir there are two solutions. hypoosmotic environment. ifferinOsmolarity:Thenetflowofwaterisfrom D T hey lose salts by diffusion and maintain water the hypoosmotic to the hyperosmotic solution. balance bydrinkingalmostnoneasmajorityofitis excreted at large amounts of dilute urine. S alts lost by diffusion arereplacedinfoodsandby uptake across the gills. OSMOREGULATORY CHALLENGES & MECHANISMS smoconformers: Consisting only some of marine O animals, are isoosmotic with theirsurroundingsand do not regulate their osmolarity. 14 Animals That Live in Temporary Waters x: Nasal glands of marine birds, which remove E excess sodium chloride from the blood. nhydrobiosis: Consisting This is an adaptation A where some aquatic invertebrates in temporary pondslosealmostalltheirbodywaterandsurvivein a dormant state. T his allows invertebrates to be able to survive in extreme conditions. (Ex: Tardigrade) nanimal’snitrogenouswastesreflectitsPhylogeny A and Habitat Land Animals Animals excrete nitrogenous wastes in different daptationstoreducewaterlossarekeytosurvival A forms: (1) ammonia, (2) urea, or (3) uric acid. on land. Toxicity:Ammonia (NH3) > Urea > Uric acid ody coverings of most terrestrial animals help B prevent dehydration. nergy Expenditure (Conversion): E Ex: Waxy layer of exoskeletons, keratinized Ammonia (NH3) < Urea < Uric acid skin cells, shells of snails esertanimalsgetmajorwatersavingsfromsimple D anatomical features and behaviors such as nocturnal lifestyle. L and animals maintain water balance by eating moist food and producing water metabolically through cellular respiration. NERGETICS OF OSMOREGULATION E Osmoregulators must expend energy to maintain osmotic gradients. T he amount of energy differs based on the following: Howdifferenttheanimal’sosmolarityisfrom its surroundings How easily water and solutes move across quatic animals are able to utilize their A the animal’s surface environment to take in lots of water so that when The work required to pump solutes across their waste is released, the ammonia is already the membrane diluted through the environment. Transport Epithelia in Osmoregulation pithelial cells specialized for moving solutes in E specific directions. T hese are typically arranged into complex tubular networks. 15 EXCRETORY PROCESSES rotonephridia: It is anetworkofdead-endtubules P connected to external openings. xcretorySystems:Itregulatesthesolutemovement E between internal fluids and the external T he smallest branches of the network are capped environment. Most produce urine by refining a by a cellular unit called aflame bulb. filtratederived from body fluids. T hese tubules excrete a dilutefluidandfunctionin T he key functions of most excretory systems areof osmoregulation. the following: Filtration:Filtering of body fluids Reabsorption:Reclaiming valuable solutes ecretion: Adding nonessential solutes and S wastes to the filtrate xcretion: E Processed filtrate containing nitrogenous wastes is released from the body. T he cilia inside the flame bulb draws in interstitial fluid. The interstitial fluid will then be filtered and absorbed by the flame bulb. The waste will then pass through the tubule and will then exit through the opening in the wall. etanephridia: It consists of tubules that collect M coelomic fluid and produce dilute urine for excretion. It functions in excretion and osmoregulation. Each segment of an earthworm has a pair of open-ended metanephridia. SURVEY OF EXCRETORY SYSTEMS S ystemsthatperformbasicexcretoryfunctionsvary widely among animal groups. T hese include: protonephridia, metanephridia, malpighian tubules, and kidneys. T he cilia d raws coelomic fluid from the internal opening. The fluid will then pass through the 16 ollecting tubule. It will then be stored in the c bladder until released from the external opening. alpighian Tubules: It removes nitrogenous waste M from hemolymph in insects and other terrestrial arthropods. It functions in osmoregulation. Insects produce a relatively dry waste matter, mainly uric acid, an important adaptation to terrestrial life. Some insects canalsotakeupwater from the air. T ake note of the renal cortex, renal medulla, and renalpelvis.Urineisexcretedintherenalpelvis.The Nephron is the site of the four processes. T he NEPHRON is organized for stepwise processing of blood filtrate T he filtrate produced in #1 Bowman’s capsule (Glomerulus) contains: (1) salts, (2) glucose, (3) amino acids, (4) vitamins, (5) nitrogenous wastes, and (6) other small molecules. S alt, water, and nitrogenous waste will be transported by transport epithelia to the lumen of theMalpighianTubules.Itwillthenpassthroughthe rectum for reabsorption and the feces and uric acid will then be excreted from the anus. IDNEYS K The excretory organs of vertebrates, function in both excretion and osmoregulation. The numerous tubules of kidneys are highly organized. Italsoincludesductsandotherstructuresthatcarry urine fromthetubulesoutofthekidneyandoutof T he blood is filtered in the Bowman’s capsule the body. (which contains the Glomerulus) 17 From Blood Filtrate to Urine ncethefiltratehasexitedtheBowman’scapsule, O it will then enter the Proximal Tubule. scending Limb of the Loop of Henle: Salt but not A water is able to diffuse from the tubule into the roximal Tubule: Reabsorption of ions, water, and P interstitial fluid. The filtrate becomes exceedingly nutrients takes place in the proximal tubule. dilute. escending Limb of the Loop of Henle: D istal Tubule: Regulates the K+ and NaCl D Reabsorption of water continues through the concentrations of body fluids. The controlled channels formed by aquaporin proteins. movementofions(H+ andHCO3-)contributestopH regulation. ovement is driven by the high osmolarity of the M interstitialfluid,whichishyperosmotictothefiltrate. 6 Collecting Duct: This carries filtrate through the # This allows for rapid reabsorption of water. The medulla to the renal pelvis. Its main task is filtrate becomes exceedingly concentrated. reabsorbing solutes and water. Urine is hyperosmotic to body fluids (concentrated again). Concentrating Urine in the Mammalian Kidney s the filtrate flows to the descending limb of the A loopofHenle,solutesbecomemoreconcentrated due to water leaving the tubule by osmosis. 18 aCldiffusingfromtheascendinglimbmaintainsa N mphibians: Kidney functionissimilartofreshwater A high osmolarity in the interstitial fluid of the renal fishes.Theyconservewateronlandbyreabsorbing medulla. water from the urinary bladder. T he countercurrent multiplier system involving the arine Bony Fishes: They are hyperosmotic M loopofHenlemaintainsahighsaltconcentrationin compared totheirenvironment.Theirkidneyshave the Kidney. small glomeruli and some lack it entirely. Filtration rates are lowand very little urine is excreted. OMEOSTATIC REGULATION OF THE KIDNEY H A combination of nervous and hormonal controls manages the osmoregulatory functions of the mammalian kidney. T hese controls contribute to homeostasis for blood pressure and blood volume. ntidiuretic Hormone (ADH) / Vasopressin: A Osmoreceptor cells in the hypothalamus monitor bloodosmolarityandregulatereleaseofADHfrom the posterior pituitary. hen osmolarity rises above its set point, ADH W release into the bloodstream increases. ADAPTATIONS OF VERTEBRATE KIDNEYS TO DIVERSE inding of ADH to receptors leads to a temporary B ENVIRONMENTS increaseinthenumberofaquaporinproteinsinthe Variations in nephron structure and functionequip membrane of collecting duct cells. the kidneys of different vertebrates for osmoregulation in various habitats. T his reduces urine volume and lowers blood osmolarity. ammals: Those that inhabit dry environments M havelongloopsofHenle.Thoseinfreshwaterhave relatively short loops. irds: They have shorter loops of Henle than B mammalsdo,butconservewaterbyexcretinguric acid instead of urea. (Uric acid is the bestformof waste to reduce water loss due to its high energy conversion) eptiles: They excrete nitrogenous waste as uric R acid.Otherreptileshaveonlycorticalnephronsbut reabsorb water from wastes in the cloaca. F reshwater Fishes: They conserve salt in their distal tubules and excrete large volumes of very dilute urine. 19
