Look up seta in Wiktionary, the free dictionary.

Setae on the toes of a gecko

Seta /ˈsiːtə/, plural: setae /ˈsiːtiː/, is a biological term derived from the Latin word for "bristle". It refers to a number of different bristle- or hair-like structures on living organisms.

Animal setae [link]

In zoology, most "setae" occur in invertebrates.^{[citation needed]}

• Setae in annelids are stiff bristles present on the body. They help for example earthworms to attach to the surface and prevent backsliding during peristaltic motion. These hairs are what make it difficult to pull a worm straight from the ground. Setae in oligochaetes (a group including earthworms) are largely composed of chitin.^[1] They are classified according to the limb to which they are attached; for instance, notosetae are attached to notopodia; neurosetae to neuropodia.^[2]
• Setae on the legs of krill and other small crustaceans help them to gather phytoplankton. It captures them and allows them to be eaten.
• Setae in entomology are often called hairs or chaetae. They are unicellular and formed by the outgrowth of a single epidermal cell (trichogen). They are generally hollow and project through a secondary or accessory (tormogen) cell as it develops. The setal membrane is not cuticularized and movement is possible. This serves to protect the body.
• Setae on gecko footpads are small hair-like processes that play a role in the animal's ability to cling to vertical surfaces. The micrometer-scale setae branch into nanometer-scale projections called spatulae on the footpads of geckos.^[3]

Fungal setae [link]

In mycology, "setae" refer to dark brown, thick-walled, thorn-like cystidia found in corticioid and poroid fungi in the family Hymenochaetaceae.^[4] Though mainly microscopic, the setae of some species may be sufficiently prominent to be visible with a hand lens.

Plant setae [link]

In botany, "seta" refers to the stalk supporting the capsule of a moss, hornwort or liverwort, and supplying it with nutrients. The seta is part of the sporophyte and has a short foot embedded in the gametophyte on which it is parasitic. Setae are not present in all mosses, but in some species they may reach 15 to 20 centimeters in height.^[5]

Synthetic setae [link]

Synthetic setae are a class of synthetic adhesives that detach at will, sometimes called resetable adhesives, yet display substantial stickiness. The development of such synthetic materials is a matter of current research.^[3][6][7]

See also [link]

• Chaeta
• Synthetic setae
• Van der Waals force

References [link]

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