
''
Eponychium'' is the anatomical term for the human cuticle
In
biology, the term 'cuticle' or 'cuticula' is given to a variety of tough but flexible, non-mineral outer coverings of an organism, or part of an organism, that provide protection. They are non-homologous, differing in their origin, structure and chemical composition.
In
zoology, the
invertebrate cuticle or cuticula is a multi-layered structure outside the
epidermis of many invertebrates, notably
roundworms
[1] and
arthropods, in which it forms an
exoskeleton.
The main structural components of the nematode cuticle are
proteins, highly cross-linked
collagens and specialised insoluble proteins known as "cuticlins", together with
glycoproteins and
lipids.
[2].
The main structural component of arthropod cuticle is a polysaccharide,
chitin, composed of
n-acetyl glucosamine units, together with proteins and lipids.
In
human anatomy, cuticle refers to the dead layers of
epidermal cells or
keratinocytes that produce the
horn protein keratin, to the strip of dead
skin cells at the base and sides of the fingernail, the
eponychium and also to the superficial layer of overlapping cells covering the
hair shaft (cuticula pili) that locks the hair into its
follicle.

Epicuticular wax covering the
cuticle of a leaf of ''
Hosta sieboldiana'' makes it
hydrophobic. Water, unable to
wet the cuticle, beads up and runs off, carrying dust and soluble contamination with it. This property of self-cleaning ultrahydrophobicity is known as the ''
Lotus''
effect
In
botany,
plant cuticles are protective
waxy coverings produced by the epidermal cells of leaves, young shoots and all other
aerial plant organs.
The main structural components of
plant cuticles are the unique
polymers cutin and/or
cutan, impregnated with
wax.
The cuticles of plants function as permeability barriers for water and water-soluble materials. The cuticle both prevents plant surfaces from becoming
wet and helps to prevent plants from drying out.
Xerophytic plants such as
Cactus have very thick cuticles to help them survive in their arid climates. Plants that live in range of sea's spray also tend to have thicker cuticles, to protect them from the toxic effects of
salt.
References
1. ''About the roundworm cuticle''
2. Page, A.P. and Johnstone, I.L. (March 19, 2007) ''The cuticle'', In: WormBook, ed. by J. M. Kramer & D. G. Moerman. The C. elegans Research Community, WormBook, doi/10.1895/wormbook.1.138.1, [1]