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Information about Metanephridium

Nephridia are invertebrate organs which function similarly to kidneys. They remove metabolic wastes from an animal's body. They are present in many different invertebrate lines. There are two basic types, metanephridia and protonephridia.

Metanephridia

A metanephridium (pl. metanephridia) is a type of excretory gland or nephridium found in many types of invertebrates such as annelids, arthropods and molluscs. It typically consists of a ciliated funnel opening into the body cavity or coelom connected to a duct which may be variously glandularized, folded or expanded (vesiculate) and which typically opens to the organism's exterior. These ciliated tubules pump water carrying surplus ions, metabolic waste, toxins from food, and useless hormones out of the organism through openings known as nephrostomes. The primary urine produced by filtration of blood (or a similar functioning component) are modified into secondary urine through selective reabsorption by the cells lining the metanephridium.

In many earthworms the nephridial ducts open into the digestive tract instead, a condition known as enteronephry.

Protonephridia

A protonephridium is a network of dead-end tubules lacking internal openings. The ends are called "flame cells" (if cilliated, "solenocytes" if flagellated), they function in osmoregulation. The terminal cells are located in the bottom of the protonephridium. Each cell has one or several cilia and when they beat inside the protonephridial tube they create an outward going current and hence a partial vacuum in the bottom of the tube. Because of this partial vacuum waste fluids from the inside of the animal are pulled through small perforations in the terminal cells and into the protonephridium. The perforations in the terminal cell are so large that small molecules can pass whereas larger proteins are retained in the animal. From the bottom of the protonephridium the waste fluid is led through the tube, formed by the canal cells, and exits the animal from a small opening formed by the nephridiopore. Protonephridia are found in simpler organisms such as flatworms.
The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. The medical field that studies the kidneys and diseases of the kidney is called nephrology[1].
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Metabolism is the complete set of chemical reactions that occur in living cells. These processes are the basis of life, allowing cells to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories.
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Excretion is the process of eliminating waste products of metabolism and other non-useful materials.[1] It is an essential process in all forms of life.

In single-celled organisms, waste products are discharged directly through the surface of the cell.
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gland is an organ in an animal's body that synthesizes a substance for release such as hormones, often into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland).
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Invertebrate is an English word that describes any animal without a spinal column. The group includes 97% of all animal species — all animals except those in the Chordate subphylum Vertebrata (fish, reptiles, amphibians, birds and mammals).
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Annelida
Lamarck, 1809

Classes and subclasses

Class Polychaeta (paraphyletic?)
Class Clitellata*
   Oligochaeta - earthworms, etc.
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Arthropoda
Latreille, 1829

Subphyla and Classes
  • Subphylum Trilobitomorpha
  • Trilobita - trilobites (extinct)
  • Subphylum Chelicerata

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Mollusca
Linnaeus, 1758

Classes

Caudofoveata
Aplacophora
Polyplacophora
Monoplacophora
Bivalvia
Scaphopoda
Gastropoda
Cephalopoda
† Rostroconchia
† Helcionelloida
† ?Bellerophontida
The molluscs
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The abdominal cavity is the body cavity of the human body (and other animal bodies) that holds the bulk of the viscera and which is located below (or inferior to) the thoracic cavity, and above the pelvic cavity.
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A duct may refer to:
  • Duct (HVAC) (Heating Ventilating and Air-Conditioning), for transfer of air between spaces in a building
  • Duct (anatomy), various ducts in anatomy and physiology
  • Ducted fan, motor for aircraft
  • Duct tape
Telecommunication

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Plantae
  • Chromalveolata
  • Heterokontophyta
  • Haptophyta
  • Cryptophyta
  • Alveolata

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    • ion is an atom or molecule which has lost or gained one or more electrons, making it positively or negatively charged. A negatively charged ion, which has more electrons in its electron shells than it has protons in its nuclei, is known as an anion
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    Metabolic wastes or excretes are substances left over from metabolic processes, which cannot be used by the organism (they are surplus or have lethal effect), and must therefore be excreted.
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    toxin (Greek: τοξικόν, toxikon, lit. (poison) for use on arrows) is a poisonous substance produced by living cells or organisms.
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    Food is any substance, usually composed primarily of carbohydrates, fats, water and/or proteins, that can be eaten or drunk by an animal or human being for nutrition or pleasure.
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    hormone (from Greek όρμή - "to set in motion") is a chemical messenger that carries a signal from one cell (or group of cells) to another. All multicellular organisms produce hormones (including plants - see phytohormone).
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    Nephrostome is the funnel-like component of a metanephridium. It is always oriented towards the coelom. The nephrostome is covered from the inside with cilia, which push the water, metabolic wastes, unnecessary hormones and other substances into the metanephridium.
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    Urine is a liquid produced by animals through the kidney, and is collected in the bladder and excreted through the urethra.

    Urine formation helps to maintain the balance of minerals and other substances in the body.
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    Filtration is the processe of using a filter to mechanically separate mixtures. Depending on the application, either one or both of the components may be isolated. Examples of filtration include A) a coffee filter to keep the coffee separate from the grounds and B) the use of HEPA
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    Selective reabsorption takes place in the proximal convoluted tubule (PCT) of the kidney. It is the process by which certain substances that are required by the body (such as glucose, amino acids, vitamins and water) but have been filtered out of the blood during ultrafiltration,
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    Lumbricina

    Families

      Acanthodrilidae
      Ailoscolecidae
      Alluroididae
      Almidae
      Criodrilidae
      Eudrilidae
      Exxidae
      Glossoscolecidae
      Lumbricidae
      Lutodrilidae
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    A tubule is a very small tube or fistular structure.

    In anatomy, a tubule is a minute tube lined with glandular epithelium.
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    A flame cell is a specialized excretory cell found in the Platyhelminthes (except the tubellarian order Acoela); these are the simplest animals to have a dedicated excretory system. Flame cells function like a kidney, removing waste materials.
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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.
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    cilium (plural cilia) is an organelle found in eukaryotic cells. Cilia are thin, tail-like projections extending approximately 5–10 micrometers outwards from the cell body.
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    A vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than standard atmospheric pressure. The Latin term in vacuo is used to describe an object as being in what would otherwise be a vacuum.
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    Metabolic wastes or excretes are substances left over from metabolic processes, which cannot be used by the organism (they are surplus or have lethal effect), and must therefore be excreted.
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    molecule is defined as a sufficiently stable electrically neutral group of at least two atoms in a definite arrangement held together by strong chemical bonds.[1][2] In organic chemistry and biochemistry, the term molecule
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    Proteins are large organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues.
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