When a Hydra is cut in half, each half will regenerate and form into a small Hydra the "head" will regenerate a "foot" and the "foot" will regenerate a "head". Hydras have two significant structures on their body: the "head" and the "foot". These stem cells will continually renew themselves in the body column. A single Hydra is composed of 50,000 to 100,000 cells which consist of three specific stem cell populations that will create many different cell types. Hydramacin is a bactericide recently discovered in Hydra it protects the outer layer against infection. The cells making up these two body layers are relatively simple. The outer layer is the epidermis, and the inner layer is called the gastrodermis, because it lines the stomach. The layers are separated by mesoglea, a gel-like substance. Hydra has two main body layers, which makes it " diploblastic". This can paralyze the prey, especially if many hundreds of nematocysts are fired. Upon contact with prey, the contents of the nematocyst are explosively discharged, firing a dart-like thread containing neurotoxins into whatever triggered the release. At the narrow outer edge of the cnidocyte is a short trigger hair called a cnidocil. Cnidocytes contain specialized structures called nematocysts, which look like miniature light bulbs with a coiled thread inside. Each tentacle, or cnida (plural: cnidae), is clothed with highly specialised stinging cells called cnidocytes.
Lernaean hydra free#
Gland cells in the basal disc secrete a sticky fluid that accounts for its adhesive properties.Īt the free end of the body is a mouth opening surrounded by one to twelve thin, mobile tentacles. Hydra has a tubular, radially symmetric body up to 10 mm (0.39 in) long when extended, secured by a simple adhesive foot known as the basal disc. Schematic drawing of a discharging nematocyst Biologists are especially interested in Hydra because of their regenerative ability they do not appear to die of old age, or to age at all. The genus was named by Linnaeus in 1758 after the Hydra, which was the many-headed beast defeated by Heracles, as when the animal had a part severed, it would regenerate much like the hydra’s heads.
They are native to the temperate and tropical regions. Hydra ( / ˈ h aɪ d r ə/ HY-drə) is a genus of small freshwater organisms of the phylum Cnidaria and class Hydrozoa.
Lernaean hydra how to#
Heracles though still had the problem of how to deal with the final immortal head of the Lernaean Hydra, but thankfully Heracles had a friend in the form of his half-sister, Athena. This second Greek monster was a gigantic crab, Carcinus, but compared to the Hydra it was an insignificant monster, and although it did manage to grab the leg of Heracles, the hero simply crushed it beneath his feet. The goddess Hera had been observing the fight between “her” monster and Heracles, and seeking to give the Lernaean Hydra an advantage, the Greek goddess sent a second monster to assist.
Thus, as Heracles removed a head, Iolaus would rush forward to cauterise the wound, and eventually only the single immortal head of the Hydra was left. Iolaus suggested that the open cuts should be cauterised before a new pair of heads could grow from it and so Heracles, with sword, and Iolaus, with flaming torched went out to face the Lernaean Hydra. Heracles briefly retreated to plan his next move, but it was actually Iolaus, Heracles’ nephew and armour bearer, who came up with the solution to the hero’s problem.
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