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Osmoregulation is the active regulation of the osmotic pressure of bodily fluids to maintain the homeostasis of the body's water content; that is it keeps the body's fluids from becoming too dilute or too concentrated. Osmotic pressure is the hydrostatic pressure produced by a difference in concentration between solutions on the two sides of a surface such as a semipermeable membrane Homeostasis (from Greek: ὅμος hómos, "equal" and ιστημι istēmi, "to stand" lit Water is a common Chemical substance that is essential for the survival of all known forms of Life. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. In Chemistry, a solution is a Homogeneous Mixture composed of two or more substances Osmosis is the Diffusion of a solvent (frequently water through a semi-permeable membrane, from a solution of low solute concentration (high water potential The higher the osmotic pressure of a solution the more water wants to go into the solution. Pressure must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water. Tonicity is a measure of blood capacity or effective osmolality in cell Biology. MembraneA biological membrane or biomembrane is an enclosing or separating Amphipathic layer that acts as a barrier within or around a cell. Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement

Animals in all environments (aquatic and terrestrial) must maintain the right concentration of solutes and amount of water in their body fluids; this involves excretion: getting rid of metabolic wastes and other substances such as hormones which would be toxic if allowed to accumulate in the blood via organs such as the skin and the kidneys; keeping the water and dissolved solutes in balance is referred to as osmoregulation. Excretion is the process of eliminating waste products of Metabolism and other non-useful materials Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products The skin is the outer covering of living tissue of an animal (or plant The kidneys are complicated organs that have numerous biological roles In Chemistry, a solution is a Homogeneous Mixture composed of two or more substances


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Regulators and conformers

Two major types of osmoregulation are osmoconformers and osmoregulators. Osmoconformers match their body osmolarity to their environment . An osmoconformer is a Marine invertebrate whose internal Salinity such that it is always equal to the surrounding seawater It can either be active or passive. Most marine invertebrates are osmoconformers, although their ionic composition may be different from that of seawater.

Osmoregulators tightly regulate their body osmolarity which always stays constant and are more common in the animal kingdom. Osmoregulators actively control salt concentrations despite the salt concentrations in the environment. An example is freshwater fish. The gills actively uptake salt from the environment by the use of mitochondria rich (MR) cells. Water will diffuse into the fish so it excretes a very hypotonic urine to expel all the excess water. Tonicity is a measure of blood capacity or effective osmolality in cell Biology. A marine fish has an internal osmotic concentration lower than that of the surrounding seawater so it tends to lose water and gain salt. Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two It actively excretes salt out from the gills. Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants A gill is an anatomical structure found in many aquatic organisms Most fish are stenohaline, which means they are restricted to either salt or fresh water and can cannot survive in water with a different salt concentration than they are adapted to. Stenohaline describes an organism usually Fish, that cannot handle a wide fluctuation in the Salt content of Water. However, some fish show a tremendous ability to effectively osmoregulate across a broad range of salinities; fish with this ability are known as euryhaline species. Euryhaline organisms are able to adapt to a wide range of salinities

Osmoregulation in plants

There are no specific osmoregulation organs in higher plants. Plants are living Organisms belonging to the kingdom Plantae. Control of water intake and loss is by means of those internal and external factors which affect the rate of transpiration.

Plants share with animals the problems of obtaining water and in disposing of the surplus. Certain plants develop methods of water conservation. Xerophytes are plants in dry habitats such as deserts which are able to withstand prolonged periods of water shortage. A xerophyte or xerophytic organism ( xero meaning dry phyte meaning plant is a Plant which is able to survive in an ecosystem with little available Succulent plants such as the cactus have water stored in large parenchyma tissues. A cactus (plural cacti) is any member of the Spine plant family Cactaceae, native to the Americas Parenchyma is a term used to describe a bulk of a substance It is used in different ways in Animals and in Plants. Other plants have leaf modifications to reduce water loss, such as needle-shaped leaves, sunken stomata and thick, waxy cuticles as in the pine. In Botany, a leaf is an above-ground Plant organ specialized for Photosynthesis. In Botany, a stoma (also stomate; plural stomata) is a tiny opening or pore found mostly on the underside of a Plant Leaf This article is about the tree For other uses of the term "pine" see Pine (disambiguation. The sand-dune marram grass has rolled leaves with stomata on the inner surface.

Oncophyorans are also osmoregulators.

Osmoregulation in protists and animals

Amoeba make use of contractile vacuoles to collect excretory waste, such as ammonia, from the intracellular fluid by both diffusion and active transport. Amoeba (sometimes amœba or ameba, plural amoebae) is a Genus of Protozoa that moves A contractile vacuole is a sub-cellular structure involved in Osmoregulation. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor As osmotic action pushes water from the environment into the cytoplasm, the vacuole moves to the surface and disposes the contents into the environment.

Kidneys play a very large role in human osmoregulation, regulating the amount of water in urine waste. The kidneys are complicated organs that have numerous biological roles With the help of naturally producing hormones such as antidiuretic hormone, aldosterone, and angiotensin II, the human body can increase the permeability of the collecting ducts in the kidney to reabsorb water and prevent it from being excreted. Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body Arginine vasopressin ( AVP) also known as vasopressin, argipressin or antidiuretic hormone ( ADH) is a Hormone found in Aldosterone is a hormone that causes the tubules of the kidneys to retain sodium and water Angiotensin causes blood vessels to constrict and drives blood pressure up

A major way animals have evolved to osmoregulate is by controlling the amount of water excreted through the excretory system. The excretory system is an organ system that performs the function of Excretion, the bodily process of discharging nitrogeneous wastes

Vertebrate excretory systems

Waste products of nitrogen metabolism

Ammonia is a toxic by-product of protein metabolism and is generally converted to less toxic substances after it is produced then excreted; mammals convert ammonia to urea while birds and reptiles form uric acid to be excreted with other wastes via their cloacas. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Reptiles, or members of the class Reptilia are air-breathing Cold-blooded Vertebrates that have skin covered in scales as opposed to hair or feathers In zoological anatomy a cloaca is the posterior opening that serves as the only such opening for the intestinal and urinary tracts of certain animal species

How osmoregulation is achieved in vertebrates

Four processes occur:

References

External links

Dictionary

osmoregulation

-noun

  1. The homeostatic regulation of osmotic pressure in the body in order to maintain a constant water content
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