Papillae (: papilla) are small, protruding structures found on the surface of certain
worm
Worms are many different distantly related bilateria, bilateral animals that typically have a long cylindrical tube-like body, no limb (anatomy), limbs, and usually no eyes.
Worms vary in size from microscopic to over in length for marine ...
s, specifically
polychaete
Polychaeta () is a paraphyletic class of generally marine Annelid, annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called c ...
s
Polychaetes (paraphyletic
Annelid
The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to vario ...
group)
In
polychaetes
Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are m ...
, these papillae are tiny, fleshy projections on the worm's body or
parapodia
In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; : parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed late ...
, often associated with sensory and locomotive functions.
Some papillae have
sensory receptors to help the worm detect
environmental change
Environment most often refers to:
__NOTOC__
* Natural environment, referring respectively to all living and non-living things occurring naturally and the physical and biological factors along with their chemical interactions that affect an organism ...
s, such as touch,
water currents, or chemical signals, and support movement by working with parapodia to aid grip and friction during crawling or burrowing.
However, papillae on the bodies of
bristle worms play a protective role, specifically in the secretion of
mucus
Mucus (, ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both Serous fluid, serous and muc ...
used to deter
predators.
References
Animal anatomy
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