What is poriferous?

What Does poriferous Mean

The poríferos , also called sponges or sponges , are aquatic animals and invertebrates , which are part of the sub - kingdom of parazoos. This means that poriferous species do not have organs, nerves or muscles, although they do have an internal skeleton made up of spicules.

Of the nine thousand species of poriferous that have been recorded throughout the planet , more than 98% live in the oceans. Until the middle of the 18th century it was considered that porifers were plants, until it was detected that they had a system to filter water and that they carried out their digestive process intracellularly.

The cells of these animals are totipotent , which implies that they can acquire different forms according to the different needs of the organism. The water enters the poriferous through the pores in its walls, the animal filters the food through the cells known as choanocytes and finally expels the water through the osculum that is in its upper region.
It is important to note that poriferous animals do not have a nervous system or digestive system. Their mobility, on the other hand, is limited, since they can barely move up to four millimeters per day.
Due to their toxicity, porifers do not usually serve as food for animal species. As they also have good resistance to pollution , sponges even manage to dominate certain ocean habitats.
Since ancient times, man has used the body of these porifers for personal hygiene ( bath sponges , although products of plant or synthetic origin are also used). Porifers are also used to fertilize crops.
With regard to the anatomy of porifers, it is possible to distinguish the following parts:
* Coanoderm : it is formed by the set of flagellate cells that make up the carpet inside a sponge and which are called choanocytes and are practically the same as the choanoflagellate protozoa, very important for food and producers of the water current . Within a coanoderm, its main cavity is called the atrium or spongocele . Its thickness can be the same as a cell, fold or generate subdivisions to give rise to clusters of separate chambers of choanocytes, according to their organization is asconoid , siconoid or leuconoid , respectively;

* Pinacoderm : the outer cells of the sponges are pseudoepithelial, wide and long in appearance and are called pinacocytes. Since they do not have a basal lamina , they do not form a layer known as the epithelium. Similar to the epidermis of a eumetazoo, the group forms a pinacocitos pinacodermo (also called ectosome ), to which passes through a large number of dermal pores , each lined with a porocito (a coiled cell). Through these pores the water penetrates and enters the body. In some cases, a layer of collagen called cuticle is identified that can replace the pinacoderm, in addition to covering it;
* mesohilo : between the two layers just described there is an area that is loosely organized and is called mesohilo . In it, it is possible to find skeletal spicules, support fibers and a large number of amoeboid cells that play a fundamental role in skeletal secretion , the transport of waste and nutrients, digestion and the production of gametes. Its elements are submerged in a colloidal mesoglea;
* skeleton : in the mesohyl there are many elastic collagen fibers and calcareous or siliceous spicules, depending on the class, which represent the mineral portion of the skeleton, which provides its rigidity and varies according to the mineral and protein proportions , making it harder or more flexible , respectively. Collagen fibers can be spongy or thin and dispersed and are intertwined with each other and with the spicules.

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