cuticle

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cuticle

1. dead skin, esp that round the base of a fingernail or toenail
2. another name for epidermis
3. any covering layer or membrane
4. the protective layer, containing cutin, that covers the epidermis of higher plants
5. the hard protective layer covering the epidermis of many invertebrates

Cuticle

 

(1) In animals, a solid formation on the surface of cells of epithelial tissue. In invertebrates, a derivative of cells of the single-layered integumental epithelium, or hypodermis. The functions of the cuticle are chiefly protective and supportive. In worms and arthropods, it forms a tough body covering. The composition of cuticle includes chitin (which, together with mineral substances and proteins, provides mechanical strength) and lipids (which make the cuticle impervious to water).

In vertebrates, which have a multilayered integumental epithelium to perform the protective function, the cuticle is found mainly on the surface of the epithelial cells that line the viscera (the intestines, the air passages of the respiratory organs, parts of the uriniferous tubules of the kidneys, and the urinary tracts). Each cell has its own cuticle, which is represented completely by the microvilli (the surface of a single cell of the small intestine in man having as many as 2,000). The activity of certain enzymes (for example, alkaline phosphatase, invertases, and maltases) has been discovered in the cuticle, testifying to the active participation of the cuticle in the functional activities of the organs.

(2) In plants, the cuticle is the thin protective film covering the epidermis of the leaves and stems and consisting of cutin. The cuticle is an unstructured formation, lacking corpuscular or fibrillar elements. It is resistant to chemical influences. It is absent in the underwater organs of aquatic plants, and it is poorly developed in plants that live in shade or damp soil. It is especially well developed in plants that must limit transpiration. The smooth, shiny cuticle of the leaves of tropical plants reflects some of the sunlight striking the plants and serves as a shield against excessive insolation. In many xerophytes, the protective properties of the epidermis are reinforced beneath the cuticle by a cuticular layer, which consists of a mixture of polysaccharides, cutin, and waxes. In the majority of xerophytes, the cuticular layer holds pale yellow pigments, which help make the cell wall impenetrable to ultraviolet rays.

M. E. ASPIZ

cuticle

[′kyüd·ə·kəl]
(anatomy)
The horny layer of the nail fold attached to the nail plate at its margin.
(biology)
A noncellular, hardened or membranous secretion of an epithelial sheet, such as the integument of nematodes and annelids, the exoskeleton of arthropods, and the continuous film of cutin on certain plant parts.
References in periodicals archive ?
The TS-D on the fourth segment was an elongated sac with a characteristic surface ornamentation of cuticular reinforment ribs (Figs.
Venom alkaloid and cuticular hydrocarbon profiles are associated with social organization, queen fertility status, and queen genotype in the fire ant Solenopsis invicta.
1980) on Locusta migratoria showed that the first cuticular secretions were essentially proteins; pre-ecdysial layers were richer in protein than post-ecdysial layers; reflecting a slowdown in protein synthesis.
If cuticular stitches are used, minimize scarring by pulling them within 5 days on the face, and within 7-10 days on the body.
Dirofilariarepens shows additional presence of external longitudinal cuticular ridges with absence of microfilaremia.
Difference in leaves cuticular wax accumulation was significant in response to salinity (Table 1).
Since Sn data is obtained using sap-flow sensors inserted in the trunk, it is not possible to know the partitioning of Sn between rehydration (water that remains in wood and organs), cuticular transpiration (smallest component) and transpiration through stomata within leaves.
2005) who concluded that cuticular wax accumulation enhanced the drought tolerance in plants.
Over 100 kinds of proteins are known to occur in insect cuticle, functions of which include pigmentation and cuticular hardness (Hopkins and Kramer 1992; Chapman 1998).
The chemical components of the PPG are mainly long chain hydrocarbons, which are also part of the profile of cuticular hydrocarbons (Bagneres & Morgan 1991, Do Nascimento et al.