Bio2#9

Bio2#9

• 1.
  Introducción a lasformas y funcionamiento de los animales Digestión y nutrición Circulación e intercambio gaseoso Sistema inmunitario Osmoregulación y excresión Hormonos y sistema endócrino Reproducción Desarrollo (embriología) Sistema nervioso (mecanismos sensitivos y motores) Comportamiento 1. Formas y funcionamiento de los Animales
• 2.
  selectively permeable membrane ---Water Hyperosmotic side:Hypoosmotic: side: Higher solute concentration lower solute concentratIOn lower free H20 concentration Higher free H20 concentration .. Figure 44.2 Solute concentration and osmosis. .. Figu euryha All confor
• 3.
  Extretion of large amountsof water in dilute urine from kidneys Osmotic water gain through gills and other parts of body surface Uptake of salt ions by gills Uptake of water and some ions in food FRESH WATER Water • Salt [,., ] (a) Osmoregulation in a saltwater fish (b) Osmoregulation in a freshwater fish ... Figure 44.4 Osmoregulation in marine and freshwater bony fishes: a comparison. fishes, such as the cod in Figure 44,4a, constantly lose water by osmosis. Such fishes balance the water loss by drinking large amounts of seawater. They then make use of both their gills and kidneys to rid themselves ofsalts. In the gills, special- water animals must be hyperosmotic because animal cells can- not tolerate salt concentrations as low as those of lake or river water. Having internal fluids with an osmolarity higher than thatoftheirsurroundings, freshwater animals face the problem Desafios osmóticos
• 4.
  Evaporatio Feces Derived fr metabolis Ingested in food(7 Ingested in liquid (1.500) Urine (1.500) Water balance in a human (2.500 mUday) Feces (0,09) Evaporation (146) Ingested in food (O.2) Derived from metabolism (1 ,8) Urine (0.45) Water balance in a kangaroo rat (2 mUday) Water gain (ml) Water loss (ml) ... Figure 44.6 Water balance in two terrestrial mam Kangaroo rats. which live in the American Southwest, eat mos se€ds and do not drink water, A kangaroo rat gains water ma lOOllm I (b) Dehydrated tardigrade ... Figure 44.5 Anhydrobi05is. Tardigrades (water bears) inhabit temporary ponds and droplets of water in soil and on moist plants (SEMs). 100llm I (a) Hydrated tardigrade inactive state, dryas dust, for a decade or more. Just add water, and within hours the rehydrated tardigrades are moving about and feeding. Anhydrobiosis requires adaptations that keep cell mem- branes intact. Researchers are just beginning to learn how tardigrades survive drying out, but studies of anhydrobiotic Evaporation (900) Feces (100) Derived from metabolism (250) Ingested in food (750) Ingested in liquid (1.500) Urine (1.500) Water balance in a human (2.500 mUday) Feces (0,09) Evaporation (146) Ingested in food (O.2) Derived from metabolism (1 ,8) Urine (0.45) Water balance in a kangaroo rat (2 mUday) Water gain (ml) Water loss (ml) ... Figure 44.6 Water balance in two terrestrial mammals. Kangaroo rats. which live in the American Southwest, eat mostly dry se€ds and do not drink water, A kangaroo rat gains water mainly from cellular metabolism and loses water mainly by evaporation during gas exchange, In contrast. a human gains water in food and drink and loses the largest fraction of it in urine. lOOllm I (b) Dehydrated tardigrade ... Figure 44.5 Anhydrobi05is. Tardigrades (water bears) inhabit temporary ponds and droplets of water in soil and on moist plants (SEMs). 100llm I (a) Hydrated tardigrade inactive state, dryas dust, for a decade or more. Just add water, and within hours the rehydrated tardigrades are moving about and feeding. Anhydrobiosis requires adaptations that keep cell mem- branes intact. Researchers are just beginning to learn how tardigrades survive drying out, but studies of anhydrobiotic roundworms (phylum Nematoda) show that desiccated indi- viduals contain large amounts ofsugars. In particular, a disac- charide called trehalose seems to protect the cells by replacing the water that is normally associated with proteins and mem- Adaptación a la anhidrobiosis
• 5.
  Nucleic acids INitrogenous bases I I -NH1 Amino groups Amino acids I Proteins I / Mostaquatic Mammals, most Many reptiles animals, including amphibians, sharks, (including birds), most bony fishes some bony fishes insects, land snails j I +0 U /', H /NH2 HN C....- N, I II C=O NH, 0=( -PC ............C ......N / 'NH o N H , H Ammonia Urea Uric acid 4 3 4 E m p a e la e e c d n a tr d c sa c M so tá O C OH R NH2 CH Desaminación Amoniaco NH3 Amoniaco NH3 H2N NH2C O Urea H N N H C O C C HN N H O C O C Ácido úrico Se requiere más energía para producir Se requiere más agua para excretar Ciclo de la urea 15 pasos O C OH R O C Cetoácidos Purinas Aminoácidos Ácidos nucleicos Desechos nitrogenados
• 6.
  Tubule proto the external e flatwormshas osmotic uptak ... Figure44.1 Protonephrid bulb system Protonephridia a internal tubules mainly in osmor oSecretion. Other substances. such as toxins and excess ions, are extracted from body fluids and added to the contents of the excretory tubule. E)Reabsorption. The transport epithelium reclaims valuable substances from the filtrate and returns them to the body fluids. GFiltration. The excretory tubule collects a filtrate from the blood. Water and solutes are forced by blood pressure across the selectively permeable membranes of a cluster of capillaries and into the excretory tubule. Excretory tubule Capillary oExcretion. The altered filtrate (urine) leaves the system and the body. ... Figure 44.10 Key functions of excretory systems: an overview. Most excretory systems produce a filtrate by pressure- filtering body fluids and then modify the filtrate's contents, This diagram is modeled after the vertebrate excretory system. Panorama general de excresión
• 7.
  usually experience anet uptake of water by osmosis through 0-0'Components of a metanephridium oInternal openlOg f) Collecting tubule e8ladder oExternal operIlf19 ..._ .../ Coelom Capillary network ... Figure 44.12 Metanephridia of an earthworm. Each segment of the WOfm contaIns a pall" of metanephndid, wtuch collect coe!orTllc flUJd from the adjacent antffiOf segment. (Only one metanephnd,um of each pair IS shown here.) 962 UNIT Sfl/(N Animal Form and Function Sistema de excresión en invertebrados Opening in body wall } FI,m, bulb Nucleus of cap cell ___ Cilia Tubule ------r cell Interstitial fluid filters through membrane where cap cell and tubule cell interlock. Tubule ............... Tubules of protonephridia flatworms hasa low soluteconcentration, helping to balance the osmotic uptake ofwater from the environment. Ir ... Figure44.11 Protonephridia: the flame bulb system of a planarian. Protonephridia are branching internal tubules that function mainly in osmoregulation, CHAPTH fORTY·fOUR Osmoregulation and Excretion 961
• 8.
  Digestive tract A Reabsorption of H20,ions, and valuable organic molecules }H dIn gut ----, Midgut (stomach) Salt, water, and Feces and urine To anus JI" nitrogenous '" (wastes"" t Malpighian tubule HEMOLYMPH 0-0'Components of a metanephridium oInternal openlOg f) Collecting tubule e8ladder oExternal operIlf19 ..._ .../ Coelom Capillary network idia of an earthworm. Each pall" of metanephndid, wtuch collect antffiOf segment. (Only one hown here.) ... Figure 44.13 Malpighian tubules of insects. Malp'9hlan tubules are outpoekettnqs of the d'9f'SllVe tract that remove mtrOl'}f'I'lOUS wastes and funCllon In osmoregUlation. Sistema escretos en artrópodos e insectos
• 9.
  Structure of theMammalian Excretory System As a prelude to exploring kidney function, let's take acloser look at the routes that fluids follow in the mammalian excretory sys- ties to the outside near thevagina in females and through the pe- nis in males. Urination is regulated by sphincter muscles dose to the junction ofthe urethra and the bladder. Distal tubule - Collecting duct 4mm Peritubular capillaries AsCending--f""'J limb Descending limb Loop of Henle (d) Filtrate and blood flow Branch of renal vein Afferent arteriole from renal artery SEM (b) Kidney structure Renal medulla Renal Cortical nephron -nephron j. Figure 44.14 The mammalian excretory system. Ureter---f--- Posterior ----I.."'""" vena cava Renal artery -,[- and vein (c) Nephron types Urinary ---!--d---'I.; bladder __ Urethra (a) Excretory organs and major associated blood vessels Sistema excretor en mamíferos
• 10.
  NaCI H,O Urea Q Collecting duct NaCI eThick segment ofascending limb eThin segment of ascending 11mb ! i -- watercontinues as the ftltrate moves into the descending limb of the loop of Henle. Here numerous water channels formed by aquaporin proteins make the transport epithelium freely perm- eable to water. In contrast, there is a nearabsence ofchannels for NH, e Descending limb of loop of Henle oProximal tubule NaCI Nutrients HC03- H20 K+ INNER MEDULLA OUTER MEDULLA CORTEX -- ]K,y H,O Salts (NaCi and others) HC03- W Urea Glucose: amino acids Some drugs ..... transport ..... transport [ Filtrate .... Figure 44.15 The nephron atld collecting duct: regional functions of the transport epithelium. The numbered regions in this diagram are keyed to the cirded numbers in the text discussJon of kidney function. DSome cells lining tubules In the kidney synthesize organicsolutes to maintain normalcell volume. Where in the kidney wooldyou find these cells? &plain. Processing of filtrate in the proximal tubule helps maintain a relatively constant pH in body fluids. Cells ofthe transport epi- thelium secrete H+ but also synthesize and secrete ammonia, which acts as a buffer to trap H+ in the form ofammonium ionsFunciones del epitelio de transporte
• 11.
  How the human tesurine: the two- o solutes contribute to interstitial fluid: NaCI Osmolarity of f Henle maintains the interstitial NaCl, which increases in fluid and decreases in the (mOsm/l) diffuses into the 300 medulla from the 100 of the urea in the filtrate I 300 ing dUd and is excreted). H,o NaCI H,O Iee trips between the irst down, then up, and CORTEX he colleding duo. As the 0 200 400 ollecting duo past H,o NaCi H,o reasing osmolarity. more NaCIhe duo by osmosis, I t Ig the solutes, including H,o NaCI H,o hind in the filtrate. NaCI drug furosemide blocks or Na' and CI in the H,O NaCi H,o e loop of Henle. What OUTER 0 400 600 600 MEDULLA pect this drug fO have H,O NaCi H,O IUrea H,O NaCI oJ H,O I I0 j 900 }I Urea IH,O NaCI H,o I'.y INNER Urea MEDULLA 1,200 1,200 Aoive transport 1.200 Passive transport Modelo de concentración de solutos
• 12.
  the water-selective channelsformed byaquaporins. Binding of ADH to receptor molecules leads to a temporary increase in the number ofaquaporin molecules in the membranes ofcol- disturb water balance by inhibiting ADH release, leading to ex- cessive urinary water loss and dehydration (which may cause some of the symptoms ofa hangover). Normally, blood osmo- // Hypothalamus nDrinking reduces blood osmolarity @to set POint. '"Increased Pituitary gland Distal tubule - { 'I H20 reab- STIMULUS'sorption helps prevent further Increase in blood osmolarity '- osmolarity Increase . Collecting duct Homeostasis: Blood osmolarity (300 mOsrrv1..) oVesicles containing aquaporin water channels are inserted into membrane lining lumen. INTERSTITIAL FlUID to membrane ADH receptof. ADH cAMP receptor eReceptor / ·_"""'!-_:"'_Jactivates cAMP second- messenger Second messenger system. Signaling molecule I-Storage f': vesicle COlLECTING DUCT CELL • Exocytosis_ . / / water H20 channels + Aquaporin channels "H20_ enhance reabsorption of water from collecting duct. COLLECTING DUCT LUMEN (b) ADH acts on the collecting duet of the kidney to promote increased reabsorption of water, Osmoreceptors in hypothalamus trigger release of ADH. Thirst r:;::::- (a) The hypothalamus contributes to homeostasIs for blood osmolarity by triggering thirst and ADH release, 970 UNIT SEVEN Animal Form and Function ... Figure 44.19 Regulation of fluid retention by antidiuretic hormone (ADH). STIMULUS: low blood volume or blood pressure (for example. due to dehydration or blood loss) Homeostasis: Blood pressure. Juxtaglomerular apparatus (JGA) Adrenal gland JGA releases renin sure by constricting arterioles, which decreases blood flow to many capillaries, including those ofthe kidney. Angiotensin II also stimulates the adrenal glands to release a hormone called aldosterone. This hormone acts on the nephrons' distal Liver jj 17 20 18 196 Permeability (p.m/s) Aquaporin protein j None Wild·type aquaporin Aquaporin mutant 2 Aquaporin mutant 1 Injected RNA SOURCE p, M T. Deen et ill,. Requirement of human renill for of unne, xierlce 26492-95(1994). cakulated the permeability of the oocytes to water, CONCLUSION Because each mutation inactivates aquaporin as awater channel, the patient's disorder can be attributed to these mutations. RESULTS oPrepare copies Aquaporin /'of human aqua- porin genes: Promoter two mutants plus wild type f) Synthesize RNA Mutant 1 Mutant 2 Wild type transcripts. I I I H,O (controll 8 Inject RNA I into frog oocytes, oTransfer to 10 mOsm solution and observe results. _iW"'I. If you measured ADH levels in patients with ADH re- ceptor mutations and in patients with aquaporm mutations. what would you expect to find. compared with wild-type subjects? volume ... Figure 44.21 Regulation of blood volume and pressure by the renin-angiotensin-aldosterone system (RAAS). (HAPTH fORTY·fOUR Osmoregulation and Excretion 971 Regulación hormonal
• 13.
  ción del cuerpoc 10 Describir la regul por la hormona a aldosterona y el p El sistema urinari urinaria y conducto rio humano se mue la “parte baja de la gigantes de color ro riñón está cubierto La porción externa médula renal. La m nicas denominadas una papila renal. C conductos colecto Cuando se pro res por una papila r embudo. Luego, la conductos que con órgano extraordina de orina. El vaciado queño al de una nu epitelio especializad y expandirse de ma Durante la mic uretra, un conduc HÍGADO TODAS LAS CÉLULAS Descomposición de hemoglobina Desechos produci- dos Respiración celular Dese- chos Ácido úrico Urea Pigmentos biliares Agua Bióxido de carbono Órganos de excre- ción RIÑÓN SISTEMA DIGESTIVO PIEL PULMONES Aire exhalado que contiene vapor de agua y bióxido de carbono SudorHecesOrinaExcreción Descomposición de ácidos nucleicos Desaminación de aminoácidos (b) Eliminación de desechos metabólicos en humanos y otros mamíferos terrestres. Para conservar agua, los mamíferos producen