BIOLOGY 457/657 PHYSIOLOGY OF MARINE & ESTUARINE ANIMALS - PowerPoint PPT Presentation

Loading...

PPT – BIOLOGY 457/657 PHYSIOLOGY OF MARINE & ESTUARINE ANIMALS PowerPoint presentation | free to download - id: 3afb50-ZTQ3M



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

BIOLOGY 457/657 PHYSIOLOGY OF MARINE & ESTUARINE ANIMALS

Description:

BIOLOGY 457/657 PHYSIOLOGY OF MARINE & ESTUARINE ANIMALS February 18, 2004 Osmoregulation in Marine Vertebrates A COMPARISON OF VERTEBRATE & INVERTEBRATE ... – PowerPoint PPT presentation

Number of Views:72
Avg rating:3.0/5.0
Slides: 23
Provided by: facultyPn
Learn more at: http://faculty.pnc.edu
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: BIOLOGY 457/657 PHYSIOLOGY OF MARINE & ESTUARINE ANIMALS


1
BIOLOGY 457/657PHYSIOLOGY OF MARINE ESTUARINE
ANIMALS
  • February 18, 2004
  • Osmoregulation in Marine Vertebrates

2
A COMPARISON OF VERTEBRATE INVERTEBRATE
OSMOREGULATION
3
VERTEBRATE OSMOREGULATION OVERVIEW
4
VERTEBRATE OSMOREGULATION
  • Two Major Vertebrate Groups
  • Fish Amphibians (evolved in water)
  • Reptiles, Birds, Mammals (evolved in air to
    these animals, seawater is a desert)
  • It is thought that the first modern vertebrates
    evolved in freshwater, because their solute
    levels are low. However, some primitive fishes
    have solute concentrations very similar to
    seawater.
  • Modern fishes must have returned to the ocean
    from freshwater. Some fish alternate between
    habitats
  • Anadromous breed in FW, live as adults in SW
  • Catadromous breed in SW, live as adults in
    estuaries

5
OSMOREGULATION IN FISHES
6
FISHES I CYCLOSTOMES
  • Cyclostomes (Class Agnatha) are jawless,
    primitive fish.
  • Hagfishes (marine) are isosmotic, using FAA to
    adjust ?.
  • Lampreys (freshwater or anadromous)
  • are like teleosts, with excellent Na
  • transport systems Kt (Na) 0.13
  • mM in gill tissue.

7
FISHES II ELASMOBRANCHS
  • Elasmobranchs (Class Condrichthyes sharks
    rays) are generally marine, with a few freshwater
    species (e.g. Amazon ray, bull sharks of Lake
    Nicaragua)
  • Their inorganic solute
  • concentrations are similar
  • to those of teleosts (bony
  • fishes). The deficit is
  • made up using organic solutes.

8
ELASMOBRANCHS (2)
  • The shark kidney actually reabsorbs urea, back
    into the blood. Shark proteins are highly
    tolerant of elevated urea.
  • Total osmoticity is usually slightly gt 1000 mOsm,
    so water continually enters by osmosis (for
    metabolism and urine formation)
  • Freshwater elasmobranchs excrete urea, reduce
    drinking, and increase salt uptake (perhaps by
    the gills or digestive tract).

9
CLASS CROSSOPTERYGII
  • The lobe-fin fishes, represented today only by
    the coelacanth (genus Latimeria), are ancestral
    to all terrestrial vertebrates.
  • Physiologically (with regard to osmoregulation),
    they are like the elasmobranchs.

10
CLASS TELEOSTII (Bony Fishes)
  • All teleosts have similar blood osmolality, about
    25 to 40 of seawater. Many species occupy both
    fresh and salt water.
  • The Osmotic Problem

11
MARINE FISHES
  • Are hyposmotic
  • LOSE water
  • through the gills,
  • body surface, and
  • in wastes.
  • DRINK seawater
  • (a flounder drinks
  • about 1 of its
  • mass per hour)
  • Are hypoionic
  • GAIN salts across gills, body surface, and in
    food.
  • EXCRETE salts (Na, Cl-) across gills. Other ions
    (K, Ca, Mg, SO4) are excreted by the kidney
    in the hypotonic urine, by tubular secretion.

12
MARINE FISHES
  • Chloride Cells Sites of ion transport in fish
    gills.
  • Cations (Na, K) are cotransported with Cl- ions
    at the basal surface. Cl- passive passes out of
    anion channels at the apical surface, and Na
    follows through leaky tight junctions between
    cells.

13
FRESHWATER FISHES
  • Are hyperosmotic, and gain water in food, across
    the gill, and across the body surface.
  • Excrete a dilute, copious urine (up to 400
    ml/kg/day).
  • Are hyperionic, and lose salts in urine and by
    diffusion.
  • Import salts in diet and by active transport at
    the gill.

14
EURYHALINE FISHES
  • Example Xiphister (blenny)
  • (Must shift between modes)

15
CLASS AMPHIBIA
  • Most amphibians are freshwater or terrestrial,
    but a few are euryhaline. Most are
    ammonicotelic, but some euryhaline species are
    ureotelic. Euryhaline species actually
    osmoconform at elevated salinities, using ions or
    urea.

16
CLASS REPTILIA
  • Reptiles are essentially terrestrial, but some
    species live in freshwater, marine, or estuarine
    habitats. All are uricotelic. However, the
    estuarine diamondback terrapin (Malaclemys)
    actually uses urea as an osmotic effector!
  • Marine species (turtles, crocodiles, snakes,
    iguana) produce an isotonic urine and excrete
    salt using extrarenal salt glands.

17
CLASS REPTILIA
  • SALT GLANDS
  • Marine Iguana nasal gland, sneezes
  • Snakes, Turtles - supraorbital gland, drain
    secretions into the orbit (turtles) or oral
    cavity (snakes)
  • Crocodiles sublingual salt glands, drain into
    oral cavity

18
CLASS AVES
  • Like reptiles, birds are essentially terrestrial
    animals, but have many successful marine species
    (and are more diverse than any other
    air-breathing vertebrate). All reproduce on
    land. Urine is hypotonic or isotonic. All are
    uricotelic.
  • Marine birds have a large extrarenal
  • pair of salt glands external to the
  • skull, producing a concentrated solution of NaCl.

19
CLASS AVES
  • Salt-gland secretion by a herring gull. The
    gland uses a countercurrent mechanism to
    concentrate salt in the secretion, and can
    transport salt at up to 20x the rate (per gram of
    tissue) as a human kidney.

20
CLASS MAMMALIA
  • All marine mammals are secondarily evolved from
    terrestrial ancestors. They form a diverse group
    of animals pinnipeds, sirenians, otters, and
    cetaceans.
  • Many marine mammals gain water from their food
    (e.g. other vertebrates, teleosts). Their
    kidneys can produce urine that is hypertonic NOT
    ONLY to the blood, BUT ALSO to seawater.

21
CLASS MAMMALIA
22
CLASS MAMMALIA
About PowerShow.com