What is a jellyfish

Jellyfish is a kind of aquatic invertebrate animals belonging to the phylum of Cnidaria, the jellyfish referred to here are animals of the Schypozoa class, they have two body shapes ie polyps attached to the seabed and medusa which can swim freely and in reverse cup-shaped . Generally they are 2 to 40 cm in length, but larger jellyfish can reach 1-2 meters, for example the largest species Cyanea capillata or better known as the Lion lion.

This animal has no head and mouth and its anus is located in the same hole, the side near the mouth is called oral and vice versa is called aboral. The jellyfish has tentacles filled with nematosista on its side. Medusa has a thick and elastic mesoglea, so the medusa can slide in water and reshape it as before. Jellyfish have no brain or central nervous system. But they have a neural net consisting of neurons that can respond to various stimuli. The kididos have a cilia that can detect physical contact and the senses that can detect chemicals such as odors, this combination allows the knidocytes to shoot the right target.

Knidocytes are also aroused and shoot when nearby knidocytes also shoot. The jellyfish uses its nematosist to paralyze its prey and then insert it into the mouth using its tentacles, after entering the digestive cavity, glandular cells in gastroderm secrete enzymes to digest food, the nutrients obtained are channeled throughout the body using cilia-controlled water flow in gastroderm or muscle movement. Nutrition is sent to the outer cell layer through diffusion. The rest of the indigestible food is ejected by mouth also using the flow of water