seta

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Seta (plural: setae) 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

Setae on the toes of a gecko

In zoology, most "setae" occur in invertebrates.

• 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]
• Setae on the legs of krill and other small crustaceans help them to gather phytoplankton.
• Setae in entomology are often called hairs. 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 responsible for the animal's ability to cling to vertical surfaces.

Plant setae

In botany, "seta" refers to the stalk supporting the capsule of a moss, hornwort or liverwort, and supplying it with nutrients. The seta has a short foot embedded in the gametophyte from which it grows. Setae are not present in all mosses, but in some species they may reach 15 to 20 centimeters in height.^[2]

Artificial setae

The development of adhesives that detach at will yet display substantial stickiness is of great importance for various technological fields.^[3][4]

See also

• Chaeta
• Synthetic setae
• Van der Waals force

References

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