What is the function of the nematocysts in the cnidarians?

Answer 1

The stinging cell of a cnidarian contains a sac that houses a coiled up tube, immersed in venomous toxins. When triggered to fire by touch, chemical stimuli, and/or nerve excitation, a hinged lid opens, the tube rapidly shoots out of the sac by eversion (turning inside out), penetrates the skin of its victim, and introduces its venom along the entire length of the tubule. When large numbers of these stinging cells deliver a sufficient amount of venom, the prey (or predator) is paralyzed and can no longer cause damage to the fragile jellyfish.

The entire evagination process only takes a millisecond or two. These stinging cells are some of the most sophisticated in the entire animal kingdom. They fire only once and then are re-adsorbed, to be eventually replaced by a brand new stinging cell. New nematocyte stinging cells (containing the nematocyst sac organelle) are created near the base of a tentacle from interstital stem cells. They migrate down the tentacle while developing the complex internal nematocyst structure, and eventually distribute themselves into a species specific pattern along the tentacle.

Answer 2

A cnidocyte, cnidoblast or nematocyte, is a type of venomous cell unique to the phylum Cnidaria (corals, sea anemones, hydrae, jellyfish, etc.). It evolved in these aquatic animals as a means for them to catch prey and defend themselves from predators, despite being morphologically simple, lacking a skeleton and usually being sessile; they prey on fish and crustaceans. A cnidocyte fires a structure that contains the toxin, from a characteristic sub-cellular organelle called a cnidocyst (or cnida or nematocyst). This is, for instance, responsible for the stings delivered by jellyfish.

Each cnidocyte cell contains an organelle called a cnidocyst, which comprises a bulb-shape capsule containing a coiled hollow thread-like structure attached to it. The externally-oriented side of the cell also has a hair-like trigger called a cnidocil. When the trigger is activated, the shaft of the cnidocyst penetrates the target organism, and the hollow thread is everted into it. This discharge is one of the fastest biological processes, takes no more than a few microseconds, and reaches accelerations of about 40,000g[1]. However, it has recently been shown to occur as fast as 600 nanoseconds, thus reaching an acceleration around five million G's. After penetration, the toxic content of the nematocyst is injected into the target organism. The rapid activity of the injected neurotoxins immediately paralyzes the mobile prey, thus allowing the sessile cnidarian to devour it. For otherwise this process is used for mating rituals.

Answer 3

Cnidarians use their stinging cells for capturing food and defense.

Answer 4

i think it might me a form a defence

Answer 5

cnidocytes