DOCSLIB.ORG

The Hormonal Control of Osmoregulation in Teleost Fish

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Hormonal Control of Osmoregulation in Teleost Fish Provided for non-commercial research and educational use. Not for reproduction, distribution or commercial use. This article was originally published in Encyclopedia of Fish Physiology: From Genome to Environment, published by Elsevier, and the attached copy is provided by Elsevier for the author’s benefit and for the benefit of the author’s institution, for non-commercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues who you know, and providing a copy to your institution’s administrator. All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution’s website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier’s permissions site at: http://www.elsevier.com/locate/permissionusematerial McCormick S.D. (2011) The Hormonal Control of Osmoregulation in Teleost Fish. In: Farrell A.P., (ed.), Encyclopedia of Fish Physiology: From Genome to Environment, volume 2, pp. 1466–1473. San Diego: Academic Press. ª 2011 Elsevier Inc. All rights reserved. Author's personal copy HORMONAL CONTROLS Hormonal Control of Metabolism and Ionic Regulation Contents The Hormonal Control of Osmoregulation in Teleost Fish Corticosteroids The Hormonal Control of Osmoregulation in Teleost Fish S D McCormick, USGS, Conte Anadromous Fish Research Center, Turners Falls, MA, USA Published by Elsevier Inc. Introduction: Salt and Water Balance in Fish Thyroid Hormones Cortisol The Special Case of Anadromy Prolactin Summary Growth Hormone and IGF-I Further Reading Glossary Insulin-like growth factor-I (IGF-I) A protein Adrenocorticotrophic hormone (ACTH) A protein hormone produced in the liver in response to growth hormone produced in the pituitary that causes release of hormone and acting on growth and ion regulation. cortisol from the interregnal. Na+,K+-ATPase (NKA, the sodium pump) Amajor Anadromy Life-history strategy entailing reproduction ATP-consuming ion pump that, directly or indirectly, drives and early rearing in freshwater followed by a significant many ion-regulatory processes, including maintaining growth phase in seawater. sodium and ion gradients across cell plasma membranes Apoptosis The process of programmed cell death. and being present at high levels in ionocytes. Cortisol The major corticosteroid of teleosts, produced Na+,K+,2Cl� cotransporter (NKCC) An ion- in the interrenal and acting on metabolism and ion translocating enzyme that utilizes a sodium gradient to regulation. transport Na+,K+, and Cl� into the cell. Cystic fibrosis transmembrane conductance Prolactin A protein hormone produced in the pituitary regulator (CFTR) An apical chloride channel involved acting on ion balance and reproduction. in chloride secretion. Receptor A signal transduction molecule that is Euryhaline Animals that physiologically adjust to a activated by a hormone. wide range of water salinity are considered euryhaline Stenohaline Describes an organism that cannot live in (eury ‘broad’; haline ‘salt’), in contrast to stenohaline environments that undergo large changes in salinity animals. (steno ‘narrow’). Growth hormone (GH) A pituitary protein hormone Thyroid hormones Thyroxine and triiodothyronine, controlling growth, metabolism, and ion regulation. produced in the thyroid gland and acting on Hormone Signaling molecule released by a cell that development and metabolism. either stimulates the cell of origin (autocrine), nearby Transactivation Binding of a transcription factor, such cells (paracrine), or travels via the bloodstream to as a receptor–ligand complex, to DNA resulting in distant cells (endocrine). increased gene transcription. 1466 Encyclopedia of Fish Physiology: From Genome to Environment, 2011, Vol. 2, 1466-1473, DOI: 10.1016/B978-0-1237-4553-8.00212-4 Author's personal copy Hormonal Control of Metabolism and Ionic Regulation | Osmoregulation in Teleost Fish 1467 Introduction: Salt and Water Balance As outlined above, the gills are the primary site of in Fish sodium and chloride transport, actively taking up salts in freshwater and excreting them in seawater. Most of Whether in freshwater or seawater, teleost fish maintain the recent work on the endocrine control of ion transport their plasma osmotic concentration at about one-third that in fish has focused on the gill, so this review will necessa­ of seawater (see also Osmotic, Ionic and Nitrogenous- rily be biased in this direction. It has been known for some Waste Balance: Osmoregulation in Fishes: An time that the mitochondrion-rich cell (also known as Introduction). In freshwater, this requires counteracting the chloride cell) is the site of salt secretion (see also the passive gain of water and loss of ions, and is accom- Role of the Gills: Morphology of Branchial Ionocytes plished through the production of large volumes of dilute and Osmotic, Ionic and Nitrogenous-Waste Balance: urine and active uptake of ions across the gills. In seawater, Mechanisms of Gill Salt Secretion in Marine Teleosts). teleosts must counteract the passive gain of ions and loss of There is substantial evidence indicating that the major water. This is accomplished by drinking seawater, absorb- transporters involved in salt secretion in the gill include ing water and salts across the gut, and excreting basolaterally located Na+,K+-ATPase (NKA, the sodium monovalent ions across the gills and divalent ions through pump) and Na+,K+,2Cl� cotransporter (NKCC), and an the kidney. It has been estimated that 95% of teleost apical Cl� channel that is homologous with the cystic species are stenohaline, living wholly in either freshwater fibrosis transmembrane conductance regulator (CFTR) or seawater. The remaining 5% are euryhaline, having the (Figure 1). capacity to tolerate a wide range of salinities. This trait is The site and mechanisms involved in ion uptake by the widespread among teleost lineages and has apparently gill in freshwater are less certain. Both mitochondrion - rich evolved many times, and may be one reason that teleosts cells and pavement cells may be involved in sodium and can be found in almost all aquatic habitats. chloride uptake (see also Osmotic, Ionic and Growth hormone/IGF-I Prolactin Cortisol Cortisol + H + Na PVC + − H − HCO3 Cl PVC + Na l l e PVC c y − r Cl o s Stem cell + s e Na c c A + + K + + + K + K K K K + K − Cl + − Na Cl + + + − + Na + Na Na + Cl Na + + Na Na + Na Na Na Seawater Freshwater (ion secretion) (ion uptake) Figure 1 Morphology, transport mechanisms, and hormonal control of gill chloride cells in freshwater and seawater. Chloride cells are characterized by numerous mitochondria and an extensive tubular system that is continuous with the basolateral membrane. In seawater, mitochondrion-rich cells are generally larger and contain a deep apical crypt, whereas in freshwater, there is a broad apical surface containing numerous microvilli. Growth hormone and cortisol can individually promote the differentiation of the seawater chloride cell, and also interact positively to control epithelial transport capacity. Prolactin inhibits the formation of seawater chloride cells and promotes the development of freshwater chloride cells. Cortisol also promotes acclimation to freshwater by maintaining ion transporters and chloride cells, and by interacting to some degree with prolactin PVC, pavement cell. Reproduced from McCormick SD (2001) Endocrine control of osmoregulation in teleost fish. American Zoologist 41: 781–794. Author's personal copy 1468 Hormonal Control of Metabolism and Ionic Regulation | Osmoregulation in Teleost Fish Nitrogenous-Waste Balance:MechanismsofIon in vitro. Cortisol has also been shown to increase the Transport in Freshwater Fishes). Chloride is exchanged transcription and abundance of the major transport pro­ � for HCO3 at the apical surface and leaves at the basolateral teins involved in salt secretion by the gill: NKA, NKCC, membrane moving downhill on an electrical gradient (the and CFTR. The effect of exogenous cortisol generally chloride cell being more negative than the blood). Sodium requires several days to reach its peak, suggesting that cell may enter the gill epithelia by exchange with H+,or proliferation and differentiation are required for its com­ throughanapicalNa+ channel coupled to an apical H+­ plete action. In the intestine, exogenous cortisol ATPase, and pass into the bloodstream at the basolateral gill stimulates NKA activity, together with ion and water surface through NKA. Recent work suggests that in some absorption, thus improving acclimation to high environ­ species there is also a Na+/Cl� co-transporter on the apical mental salinity. An increased drinking response after surface that is involved in ion uptake. More direct evidence transfer to seawater has been observed in salmonids trea­ is needed to be certain of the roles and location of these ted with cortisol. transporters involved in ionuptakeinteleosts. Changes in circulating cortisol in response to There are three primary lines of evidence for the increased environmental salinity are reported for many involvement of hormones in ion regulation. The first teleost species. The clearance rate (the inverse of the involves the treatment of animals (in vivo) or isolated amount of time a compound remains in circulation) of tissues (in vitro) with hormones and examining ion reg­ cortisol also increases in seawater, suggesting
Load more

Recommended publications
  • Article Evolutionary Dynamics of the OR Gene Repertoire in Teleost Fishes
    bioRxiv preprint doi: https://doi.org/10.1101/2021.03.09.434524; this version posted March 10, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Article Evolutionary dynamics of the OR gene repertoire in teleost fishes: evidence of an association with changes in olfactory epithelium shape Maxime Policarpo1, Katherine E Bemis2, James C Tyler3, Cushla J Metcalfe4, Patrick Laurenti5, Jean-Christophe Sandoz1, Sylvie Rétaux6 and Didier Casane*,1,7 1 Université Paris-Saclay, CNRS, IRD, UMR Évolution, Génomes, Comportement et Écologie, 91198, Gif-sur-Yvette, France. 2 NOAA National Systematics Laboratory, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560, U.S.A. 3Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20560, U.S.A. 4 Independent Researcher, PO Box 21, Nambour QLD 4560, Australia. 5 Université de Paris, Laboratoire Interdisciplinaire des Energies de Demain, Paris, France 6 Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, 91190, Gif-sur- Yvette, France. 7 Université de Paris, UFR Sciences du Vivant, F-75013 Paris, France. * Corresponding author: e-mail: [email protected]. !1 bioRxiv preprint doi: https://doi.org/10.1101/2021.03.09.434524; this version posted March 10, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Abstract Teleost fishes perceive their environment through a range of sensory modalities, among which olfaction often plays an important role.
    [Show full text]
  • A Review of Salinity Problems of Organisms in United States Coastal Areas Subject to the Effects of Engineering Works
    Gulf and Caribbean Research Volume 4 Issue 3 January 1974 A Review of Salinity Problems of Organisms in United States Coastal Areas Subject to the Effects of Engineering Works Gordon Gunter Gulf Coast Research Laboratory Buena S. Ballard Gulf Coast Research Laboratory A. Venkataramiah Gulf Coast Research Laboratory Follow this and additional works at: https://aquila.usm.edu/gcr Part of the Marine Biology Commons Recommended Citation Gunter, G., B. S. Ballard and A. Venkataramiah. 1974. A Review of Salinity Problems of Organisms in United States Coastal Areas Subject to the Effects of Engineering Works. Gulf Research Reports 4 (3): 380-475. Retrieved from https://aquila.usm.edu/gcr/vol4/iss3/5 DOI: https://doi.org/10.18785/grr.0403.05 This Article is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Gulf and Caribbean Research by an authorized editor of The Aquila Digital Community. For more information, please contact [email protected]. A REVIEW OF SALINITY PROBLEMS OF ORGANISMS IN UNITED STATES COASTAL AREAS SUBJECT TO THE EFFECTS OF ENGINEERING WORKS’ bY GORDON GUNTER, BUENA S. BALLARD and A. VENKATARAMIAH Gulf Coast Research Laboratory Ocean Springs, Mississippi ABSTRACT The nongaseous substances that normally move in and out of cells are metabolites, water and salts. The common salts in water determine its salinity, and the definition of sea water salinity and its composition are discussed. The relationships of salinity to all phyla of animals living in the coastal waters are reviewed, with emphasis on the estuaries of the Gulf and Atlantic coasts of the United States, which are particularly influenced by coastal engineering works and changes of salinity caused thereby.
    [Show full text]
  • Online Dictionary of Invertebrate Zoology Parasitology, Harold W
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Armand R. Maggenti Online Dictionary of Invertebrate Zoology Parasitology, Harold W. Manter Laboratory of September 2005 Online Dictionary of Invertebrate Zoology: S Mary Ann Basinger Maggenti University of California-Davis Armand R. Maggenti University of California, Davis Scott Gardner University of Nebraska-Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/onlinedictinvertzoology Part of the Zoology Commons Maggenti, Mary Ann Basinger; Maggenti, Armand R.; and Gardner, Scott, "Online Dictionary of Invertebrate Zoology: S" (2005). Armand R. Maggenti Online Dictionary of Invertebrate Zoology. 6. https://digitalcommons.unl.edu/onlinedictinvertzoology/6 This Article is brought to you for free and open access by the Parasitology, Harold W. Manter Laboratory of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Armand R. Maggenti Online Dictionary of Invertebrate Zoology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Online Dictionary of Invertebrate Zoology 800 sagittal triact (PORIF) A three-rayed megasclere spicule hav- S ing one ray very unlike others, generally T-shaped. sagittal triradiates (PORIF) Tetraxon spicules with two equal angles and one dissimilar angle. see triradiate(s). sagittate a. [L. sagitta, arrow] Having the shape of an arrow- sabulous, sabulose a. [L. sabulum, sand] Sandy, gritty. head; sagittiform. sac n. [L. saccus, bag] A bladder, pouch or bag-like structure. sagittocysts n. [L. sagitta, arrow; Gr. kystis, bladder] (PLATY: saccate a. [L. saccus, bag] Sac-shaped; gibbous or inflated at Turbellaria) Pointed vesicles with a protrusible rod or nee- one end. dle. saccharobiose n.
    [Show full text]
  • J. Mar. Biol. Ass. UK (1958) 37, 7°5-752
    J. mar. biol. Ass. U.K. (1958) 37, 7°5-752 Printed in Great Britain OBSERVATIONS ON LUMINESCENCE IN PELAGIC ANIMALS By J. A. C. NICOL The Plymouth Laboratory (Plate I and Text-figs. 1-19) Luminescence is very common among marine animals, and many species possess highly developed photophores or light-emitting organs. It is probable, therefore, that luminescence plays an important part in the economy of their lives. A few determinations of the spectral composition and intensity of light emitted by marine animals are available (Coblentz & Hughes, 1926; Eymers & van Schouwenburg, 1937; Clarke & Backus, 1956; Kampa & Boden, 1957; Nicol, 1957b, c, 1958a, b). More data of this kind are desirable in order to estimate the visual efficiency of luminescence, distances at which luminescence can be perceived, the contribution it makes to general back• ground illumination, etc. With such information it should be possible to discuss. more profitably such biological problems as the role of luminescence in intraspecific signalling, sex recognition, swarming, and attraction or re• pulsion between species. As a contribution to this field I have measured the intensities of light emitted by some pelagic species of animals. Most of the work to be described in this paper was carried out during cruises of R. V. 'Sarsia' and RRS. 'Discovery II' (Marine Biological Association of the United Kingdom and National Institute of Oceanography, respectively). Collections were made at various stations in the East Atlantic between 30° N. and 48° N. The apparatus for measuring light intensities was calibrated ashore at the Plymouth Laboratory; measurements of animal light were made at sea.
    [Show full text]
  • Report on the First Scotian Shelf Ichthyoplankton Program
    NOT TO BE CITED WITHOUT PRIOR REFERENCE TO THE AUTHOR (S) International Commission for a the Northwest Atlantic Fisheries Serial No. 5179 ICNAF Res. Doc. 78/VI/21 (D.c.1) ANNUAl MEETING - JUNE 1978 Report on the First Scotian Shelf Ichthyoplanktoll Program (SSIP) Workshop, 29 August to 3 September 1977, St. Andrews, N. B. Sponsored by Department of Fisheries and Environment Marine Fish Division Resource Branch, Maritimes Bedford Institute of Oceanography Dartmouth, Nova Scotia TABLE OF CONTENTS Page Abstract 2 Terms of Reference 2 Introduction 4 Oceanographic Regime •••••..••••.•.•.•••••••..••••••.••..•. 4 Overview of Present Approaches ••••••••••••••••••..•••.•••• 6 - Canada 6 - United States of America 13 - Un! ted Kingdom 19 - Federal Republic of Germany......................... 24 Sampling Recommendations 25 Sorting Protocols 26 Planning Sessions 26 Summary and Resolutions ••••••••.•..••...•••.••••...•.•.•.• 27 References 28 List of participants 30 Convener P. F. Lett Rapporteur: J. F. Schweigert C2 - 2 - ABSTRACT The Scotian Shelf ichthyoplankton workshop was organized to draw on expertise from other prevailing programs and to incorporate any new ideas on ichthyoplankton ecology and sampling 8S it might relate to the stock-recruitment problem and fisheries management. Experts from a number of leading fisheries laboratories presented overviews of their ichthyoplankton programs and approaches to fisheries management. The importance of understanding the eJirly life history of most fish species was emphasized and some pre! iminary reBul
    [Show full text]
  • Freshwater Fish of New River, Belize
    FRESHWATER FISH OF NEW RIVER, BELIZE Belize is home to an abundant diversity of freshwater Blue Tilapia fish species and is often considered a fisherman’s Oreochromis aureus, Tilapia paradise. The New River area is a popular freshwater Adult size: 13–20 cm (5–8 in) fishing destination in the Orange Walk district of northern Belize. Here locals and visitors alike take to the lagoons and waterways for dinner or for good sportfishing. This guide highlights the most popular species in the area and will help people identify and understand these species. A fishing license is required for all fishers, so before casting be sure to check the local laws and regulations. Tarpon Victor Atkins Megalops atlanticus This edible, fleshy fish can be identified by its overall blue Adult size: 1-2.5 m (4-8 ft) color. Adults can weigh up to 2.7kg (6 lbs). This exotic cichlid is abundant in both fresh and brackish waters. Mayan Cichlid Cichlasoma urophthalmus, Pinta Adult size: 25–27 cm (10–11 in) Albert Kok Tarpon are large fish that can weigh up to 127kg (280 lbs). They are covered in large, silver scales and have no spines in their fins, and have a broad mouth with a prominent lower jaw. Tarpon are fighters and may jump out of the water DATZ. R. Stawikowski several times when hooked. They are found in fresh and saltwater. This popular food fish has dark vertical bars and a large black eyespot with a blue border at the tail base. The first Bay Snook dorsal and anal fins have many sharp spines.
    [Show full text]
  • Fish Feeding and Dynamics of Soft-Sediment Mollusc Populations in a Coral Reef Lagoon
    MARINE ECOLOGY PROGRESS SERIES Published March 3 Mar. Ecol. Prog. Ser. Fish feeding and dynamics of soft-sediment mollusc populations in a coral reef lagoon G. P. Jones*, D. J. Ferrelle*,P. F. Sale*** School of Biological Sciences, University of Sydney, Sydney 2006, N.S.W., Australia ABSTRACT: Large coral reef fish were experimentally excluded from enclosed plots for 2 yr to examine their effect on the dynamics of soft sediment mollusc populations from areas in One Tree lagoon (Great Barrier Reef). Three teleost fish which feed on benthic molluscs. Lethrinus nebulosus, Diagramrna pictum and Pseudocaranx dentex, were common in the vicinity of the cages. Surveys of feeding scars in the sand indicated similar use of cage control and open control plots and effective exclusion by cages. The densities of 10 common species of prey were variable between locations and among times. Only 2 species exhibited an effect attributable to feeding by fish, and this was at one location only. The effect size was small relative to the spatial and temporal variation in numbers. The power of the test was sufficient to detect effects of fish on most species, had they occurred. A number of the molluscs exhibited annual cycles in abundance, with summer peaks due to an influx of juveniles but almost total loss of this cohort in winter. There was no evidence that predation altered the size-structure of these populations. While predation by fish is clearly intense, it does not have significant effects on the demo- graphy of these molluscs. The results cast doubt on the generality of the claim that predation is an important structuring agent in tropical communities.
    [Show full text]
  • ZOOLOGY Animal Physiology Osmoregulation in Aquatic
    Paper : 06 Animal Physiology Module : 27 Osmoregulation in Aquatic Vertebrates Development Team Principal Investigator: Prof. Neeta Sehgal Department of Zoology, University of Delhi Co-Principal Investigator: Prof. D.K. Singh Department of Zoology, University of Delhi Paper Coordinator: Prof. Rakesh Kumar Seth Department of Zoology, University of Delhi Content Writer: Dr Haren Ram Chiary and Dr. Kapinder Kirori Mal College, University of Delhi Content Reviewer: Prof. Neeta Sehgal Department of Zoology, University of Delhi 1 Animal Physiology ZOOLOGY Osmoregulation in Aquatic Vertebrates Description of Module Subject Name ZOOLOGY Paper Name Zool 006: Animal Physiology Module Name/Title Osmoregulation Module Id M27:Osmoregulation in Aquatic Vertebrates Keywords Osmoregulation, Active ionic regulation, Osmoconformers, Osmoregulators, stenohaline, Hyperosmotic, hyposmotic, catadromic, anadromic, teleost fish Contents 1. Learning Objective 2. Introduction 3. Cyclostomes a. Lampreys b. Hagfish 4. Elasmobranches 4.1. Marine elasmobranches 4.2. Fresh-water elasmobranches 5. The Coelacanth 6. Teleost fish 6.1. Marine Teleost 6.2. Fresh-water Teleost 7. Catadromic and anadromic fish 8. Amphibians 8.1. Fresh-water amphibians 8.2. Salt-water frog 9. Summary 2 Animal Physiology ZOOLOGY Osmoregulation in Aquatic Vertebrates 1. Learning Outcomes After studying this module, you shall be able to • Learn about the major strategies adopted by different aquatic vertebrates. • Understand the osmoregulation in cyclostomes: Lamprey and Hagfish • Understand the mechanisms adopted by sharks and rays for osmotic regulation • Learn about the strategies to overcome water loss and excess salt concentration in teleosts (marine and freshwater) • Analyse the mechanisms for osmoregulation in catadromic and anadromic fish • Understand the osmotic regulation in amphibians (fresh-water and in crab-eating frog, a salt water frog).
    [Show full text]
  • Growth, Tolerance to Low Salinity, and Osmoregulation in Decapod Crustacean Larvae
    Vol. 12: 249–260, 2011 AQUATIC BIOLOGY Published online June 1 doi: 10.3354/ab00341 Aquat Biol Growth, tolerance to low salinity, and osmoregulation in decapod crustacean larvae Gabriela Torres1, 2,*, Luis Giménez1, Klaus Anger2 1School of Ocean Sciences, Bangor University, Menai Bridge, LL59 5AB, UK 2Biologische Anstalt Helgoland, Foundation Alfred Wegener Institute for Polar and Marine Research, 27498 Helgoland, Germany ABSTRACT: Marine invertebrate larvae suffer high mortality due to abiotic and biotic stress. In planktotrophic larvae, mortality may be minimised if growth rates are maximised. In estuaries and coastal habitats however, larval growth may be limited by salinity stress, which is a key factor select- ing for particular physiological adaptations such as osmoregulation. These mechanisms may be ener- getically costly, leading to reductions in growth. Alternatively, the metabolic costs of osmoregulation may be offset by the capacity maintaining high growth at low salinities. Here we attempted identify general response patterns in larval growth at reduced salinities by comparing 12 species of decapod crustaceans with differing levels of tolerance to low salinity and differing osmoregulatory capability, from osmoconformers to strong osmoregulators. Larvae possessing tolerance to a wider range in salinity were only weakly affected by low salinity levels. Larvae with a narrower tolerance range, by contrast, generally showed reductions in growth at low salinity. The negative effect of low salinity on growth decreased with increasing osmoregulatory capacity. Therefore, the ability to osmoregulate allows for stable growth. In euryhaline larval decapods, the capacity to maintain high growth rates in physically variable environments such as estuaries appears thus to be largely unaffected by the energetic costs of osmoregulation.
    [Show full text]
  • Excretory Products and Their Elimination
    290 BIOLOGY CHAPTER 19 EXCRETORY PRODUCTS AND THEIR ELIMINATION 19.1 Human Animals accumulate ammonia, urea, uric acid, carbon dioxide, water Excretory and ions like Na+, K+, Cl–, phosphate, sulphate, etc., either by metabolic System activities or by other means like excess ingestion. These substances have to be removed totally or partially. In this chapter, you will learn the 19.2 Urine Formation mechanisms of elimination of these substances with special emphasis on 19.3 Function of the common nitrogenous wastes. Ammonia, urea and uric acid are the major Tubules forms of nitrogenous wastes excreted by the animals. Ammonia is the most toxic form and requires large amount of water for its elimination, 19.4 Mechanism of whereas uric acid, being the least toxic, can be removed with a minimum Concentration of loss of water. the Filtrate The process of excreting ammonia is Ammonotelism. Many bony fishes, 19.5 Regulation of aquatic amphibians and aquatic insects are ammonotelic in nature. Kidney Function Ammonia, as it is readily soluble, is generally excreted by diffusion across 19.6 Micturition body surfaces or through gill surfaces (in fish) as ammonium ions. Kidneys do not play any significant role in its removal. Terrestrial adaptation 19.7 Role of other necessitated the production of lesser toxic nitrogenous wastes like urea Organs in and uric acid for conservation of water. Mammals, many terrestrial Excretion amphibians and marine fishes mainly excrete urea and are called ureotelic 19.8 Disorders of the animals. Ammonia produced by metabolism is converted into urea in the Excretory liver of these animals and released into the blood which is filtered and System excreted out by the kidneys.
    [Show full text]
  • Marine Science Virtual Lesson Biological Oceanography Photo Credit: Getty Images
    Marine Science Virtual Lesson Biological Oceanography Photo credit: Getty Images • The study of how plants and animals interact with What is each other and their marine environment. • How organisms affect and are affected by chemical, Biological physical, and geological oceanography Oceanography? • Studies life in the ocean from tiny algae to giant blue whales Marine Environment Photo credit: Getty Images Biological Pump Some CO2 is • Carbon sink is part of the released through biological pump respiration • The pump includes upwelling that brings nutrient back up the water column • Releasing some CO2 through respiration Upwelling of nutrients Photosynthesis • Sunlight and CO2 is used to make sugar and oxygen • Can be used as fuel for an organism's movement and biological processes • Such as: circulatory system, digestive system, and respiration Where Can You Find Life in the Ocean • Plants and algae are found in the euphotic zone of the ocean • Where light reaches • Animals are found at all depths of the ocean • Most live-in the euphotic zone where there is more prey • 90% of species live and rely in euphotic zones • the littoral (close to shore) and sublittoral (coastal areas) zones Photo credit: libretexts.org Photo credit: Christian Sardet/CNRS/Tara Expéditions Plankton • Drifting animals • Follow the ocean currents (don’t swim) • Holoplankton • Spend entire lives in water column • Meroplankton • Temporary residents of plankton community • Larvae of benthic organisms Plankton 2.0 • Phytoplankton • Autotrophic (photosynthetic) Photo
    [Show full text]
  • Cartilaginous Fish: Sharks, Sawfish and Stingrays
    Cartilaginous fish: Sharks, sawfish and stingrays. It may come as a surprise to some readers that there are sharks, sawfish and stingrays in the Mekong River, because most people connect these fishes with the big oceans. Most species in these groups are in fact strictly marine. However, several species have some tolerance to freshwater and have the ability to venture far up into rivers during their searches for food, while a few live their entire life in fresh water. Sharks, sawfish and stingrays are all cartilaginous fishes (the class Chondrichthyes), while all the species we have presented in Catch and Cultures supplement series until this point have been bony fish (the class Osteichthyes). Let us therefore start by looking at the characters that distinguish cartilaginous fish from bony fishes. As implied in the name, the skeleton in cartilaginous fish does not include bone but consists of cartilage, and all Fins supported by the fins are supported by horny horny structures structures rather than fin rays. Gill openings seen as Body covered with None of the species possess a a series of slits denticles swimbladder, the organ most bony fish use to prevent them from sinking to the bottom. Many cartilaginous fish species are therefore Mouth protrusible either bottom dwellers or accomplish neutral buoyancy by Specialized teeth arranged in rows maintaining a high fat or oil content A generalized cartilaginous fish, the milk shark in their tissues. (Rhizoprionodon acutus), which has been The gill openings in cartilaginous fish are not covered recorded from the Great Lake in Cambodia. with operculae, and are seen as a series of slits on the side of the fish just behind the head, or on the underside of the fish.
    [Show full text]