Tentacle

In zoology, a tentacle is a flexible, mobile, elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work mainly like muscular hydrostats. Most forms of tentacles are used for grasping and feeding. Many are sensory organs, variously receptive to touch, vision, or to the smell or taste of particular foods or threats. Examples of such tentacles are the "eye stalks" of various kinds of snails. Some kinds of tentacles have both sensory and manipulatory functions.

The word tentillum literally means "little tentacle". However, irrespective of size, it usually refers to a side branch of a larger tentacle. In some cases such tentilla are specialised for particular functions; for example, in the Cnidaria tentilla usually bear cnidocytes, whereas in the Ctenophora they usually bear collocytes.

Invertebrates

Molluscs

Many molluscs have tentacles of one form or another. The most familiar are those of the pulmonate land snails, which usually have two sets of tentacles on the head: when extended the upper pair have eyes at their tips; the lower pair are chemoreceptors. Both pairs are fully retractable muscular hydrostats, but they are not used for manipulation or prey capture.

Tentacle (botany)

In botany, tentacles are glandular hairs on the leaves of some species of insectivorous plants such as Drosera (sundews). Tentacles are different from organs such as the tendrils of climbing plants.

In carnivorous plants such as sundews, the tentacles are the stalked glands of the upper surface of the leaves. They are hairlike projections with a drop of sticky mucilage which attract insects. Unlike a usual plant hair which is of epidermal origin, the tentacle is highly complex and includes all the tissue types present in the leaf. It consists of a tall, tapering stalk of multi-cellular structure, topped with two layers of glandular cells. They are highly touch-sensitive. When an insect or small animal is captured, the tentacles bend inward and the leaf rolls together as shown in the picture. The glandular cells then secrete enzymes to dissolve and digest the insect.

References

Tentacle (album)

Tentacle is a studio album by the Japanese noise musician, Merzbow.

Track listing

All music composed by Masami Akita.

Personnel

References