World Library  
Flag as Inappropriate
Email this Article

Seta

Article Id: WHEBN0000338271
Reproduction Date:

Title: Seta  
Author: World Heritage Encyclopedia
Language: English
Subject: Kėdainiai District Municipality, Kaunas County, Seta (disambiguation), Happy Days (play), Earthworm
Collection: Animal Hair, Fungal Morphology and Anatomy, Plant Anatomy
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Seta

Seta , plural: setae , is a organisms.

Animal setae

Invertebrates

Setae on the foreleg of a mayfly

Annelid setae 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]

[3] and can also be found on grooming limbs.[4] In some cases, setae are modified into scale like structures.[4] Setae on the legs of krill and other small crustaceans help them to gather phytoplankton. It captures them and allows them to be eaten.

Insect setae 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.

Vertebrates

Close-up of the underside of a gecko's foot as it walks on vertical glass

The pads on a gecko's feet 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.[5] • Gekko's seta : According to Kellar Autumn, "Two front feet of a tokay gecko (Gekko gecko) can withstand 20.1 N of force parallel to the surface with 227 mm2 of pad area (Irschick et al. 1996). The foot of a tokay bears approximately 3600 tetrads of setae per mrn2, or 14,400 setae per mm2 (Schleich and Kastle 1986; pers- obs-)- Consequently, a single seta should produce an average force of 6-2 pN, and an average shear stress of 0-090 N mm-l (0.9 atm). However, single setae proved both much less sticky and much more sticky than predicted by whole animal measurements, under varying experimental conditions, implying that attachment and detachment in gecko setae are mechanically controlled (Autumn et al. 2000)."[6]

Fungal setae

In mycology, "setae" refer to dark brown, thick-walled, thorn-like cystidia found in corticioid and poroid fungi in the family Hymenochaetaceae.[7] Though mainly microscopic, the setae of some species may be sufficiently prominent to be visible with a hand lens.

Plant setae

In botany, "seta" refers to the stalk supporting the capsule of a moss 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.[8]

Synthetic setae

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.[5][9][10]

See also

References

  1. ^ Hyman, H.L. (1966). "Further Notes on the Occurrence of Chitin in Invertebrates" (PDF). Biological Bulletin 130: 1–149. 
  2. ^ Butterfield, N. J. (1990). "A reassessment of the enigmatic Burgess Shale fossil Wiwaxia corrugata (Matthew) and its relationship to the polychaete Canadia spinosa Walcott". Paleobiology 16 (3): 287–303.  
  3. ^ a b Garm, A (2004). "Revising the definition of the crustacean seta and setal classification systems based on examinations of the mouthpart setae of seven species of decapods" (PDF). Zoological Journal of the Linnean Society 142: 233–252. 
  4. ^ a b Keiler, J.; Richter, S. (2011). "Morphological diversity of setae on the grooming legs in Anomala (Decapoda: Reptantia) revealed by scanning electron microscopy". Zoologischer Anzeiger 250 (4): 343–366. 
  5. ^ a b Santos, Daniel; Matthew Spenko; Aaron Parness; Kim Sangbae; Mark Cutkosky (2007). Journal of Adhesion Science and Technology 21 (12-13): 1317–1341. Gecko "feet and toes are a hierarchical system of complex structures consisting of lamellae, setae,and spatulae. The distinguishing characteristics of the gecko adhesion system have been described [as] (1) anisotropic attachment, (2) high pulloff force to preload ratio, (3) low detachment force, (4) material independence, (5) self-cleaning, (6) anti-self sticking and (7) non-sticky default state. ... The gecko’s adhesive structures are made from ß-keratin (modulus of elasticity [approx.] 2 GPa). Such a stiff material is not inherently sticky; however, because of the gecko adhesive’s hierarchical nature and extremely small distal features (spatulae are [approx.] 200 nm in size), the gecko’s foot is able to intimately conform to the surface and generate significant attraction using van der Waals forces. 
  6. ^ Properties, Principles, and Parameters of the Gecko Adhesive System
  7. ^ Kirk PM, Cannon PF, Minter DW, Stalpers JA. (2008). Dictionary of the Fungi (10th ed.). Wallingford: CABI. p. 116.  
  8. ^ Raven, Peter H.; Evert, R.F. & Eichhorn, S.E. (2005): Biology of Plants (7th ed.). W.H. Freeman and Company.
  9. ^ Engineers create new adhesive that mimics gecko toe hairs Physorg.com Jan 29, 2008
  10. ^ Setae Research
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.