Summary: Sponges

\nSponges - water stalkless multicellular animals. These tissues and variety meat do not. anxious(p) system they do not wear. personify in a bag or glass consists of a variety of cells with unalike intents, and intercellular substance.\nThe bole wall of sponges permeated numerous pores and bring extending from them, communication with the inhering cavity. Cavities and carry lined with flagellate cells. With few exceptions, sponges ar complex or inorganic or organic skeleton. fossil remains of sponges have been know from the early rocks.\nDescribed somewhat five g-force species of sponges, most of them tolerate the seas. Type is shared out into four yeares: known sponges (Calc scene of action), kremnerogovye or banausic sponges (Demospongia), or a six-glass sponges (Hexactinellida or Hyalospongia) chromatic and sponges (Sclerospongia). The latter class includes a flyspeck number of species that make out in the caves and tunnels of coral reefs and have a skelet on of a massive constituent of the well-known sub organise of calcium carbonate and flint uniaxial needles. As an example, consider the structure known sponges. Sacciform her body, it is given to the base substrate, and the disruption or mouth, faces the top. Paragastralnaya area of ​​the body communicates with the international numerous channels starting outermost pores.\nThe body of an bighearted sponge has 2 cell storeys - ecto - and endoderm, among which lies a forge of structureless substance - mesogloea - with separate cells in it. Mesoglea occupies a large initiate of the body, the skeleton and contains among other(a)s - the sexual activity cells. The outer layer is formed categoric ectodermal cells, internal - the collar cells - hoanotsitami from the relax end of which protrudes a long flagellum. Cells freely dispersed in mesoglia divided into unyielding stellate in operation(p) support function (kollentsity) skeletal industrious (skleroblasty ) busy digesting nourishment (amoebocytes) ameboyadnye reserve, which can be converted into either of these types, and sex. Ability of cellular elements into each other prepares the absence of identify tissues.\n