Cuticle

A cuticle (pronounced /ˈkjuːtɪkəl/), or cuticula, is a term used for any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticles" are non-homologous; differing in their origin, structure, function, and chemical composition. The word derives from Latin "cuticula", diminutive of "cutis", meaning "skin"[1].

Contents

Human anatomy

Eponychium is the anatomical term for the human cuticle[contradictory]

In human anatomy, cuticle (also called eponychium) refers to several structures. It 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, to the eponychium, and also to the superficial layer of overlapping cells covering the hair shaft (cuticula pili) that locks the hair into its follicle (See also Cuticle (hair)).

Invertebrate zoology

In zoology, the invertebrate cuticle or cuticula is a multi-layered structure outside the epidermis of many invertebrates, notably roundworms[2] and arthropods, in which it forms an exoskeleton (see arthropod 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.[3]

The main structural component of arthropod cuticle is chitin, a polysaccharide composed of N-acetylglucosamine units, together with proteins, lipids, and catecholamines The proteins and chitin are cross-linked by catecholamines such as N-acetyldopamine, contributing to their rigidity. The rigidity is a function of the types of proteins and the quantity of chitin and catecholamines. The more acidic the protein is, the softer the cuticle. It is believed that the epidermal cells and hemocytes (cells in the hemolymph) produce protein and also monitors the timing and amount of protein to be incorporated into the cuticle.[4]

Botany

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 self-cleaning property, is variously called "ultrahydrophobicity" or "ultralyophobicity" in technical journals. More popularly it is known as the Lotus effect.

Some plants, particularly those adapted to life in damp or aquatic environments, have an almost magical resistance to wetting. A well-known example is the Sacred Lotus[5]. This spectacular adaptation is not purely the physical and chemical effect of a waxy coating however; it depends largely on the microscopic shape of the surface. When a hydrophobic surface is sculpted into microscopic, regular, elevated areas, sometimes in fractal patterns, too high and too closely spaced for the surface tension of the liquid to permit any flow into the space between the plateaus, then the area of contact between liquid and solid surfaces may be reduced to less than a tenth of what a continuous surface might permit.[6] The effect is to reduce wetting of the surface spectacularly.[7].

In botany, plant cuticles are protective, hydrophobic, waxy coverings produced by the epidermal cells of leaves, young shoots and all other aerial plant organs. Cuticles minimize water loss and effectively reduce pathogen entry due to their waxy secretion.

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 may have thicker cuticles that protect them from the toxic effects of salt.

Mycology

"Cuticle" is one term used for the outer layer of tissue of a mushroom's basidiocarp or "fruit body". The alternative term "pileipellis", Latin for "skin" of a "cap" (meaning "mushroom")[8] might be technically preferable, but is perhaps too cumbersome for popular use. It is the part removed in "peeling" mushrooms. On the other hand, some morphological terminology in mycology makes finer distinctions, such as described in the article on the "pileipellis". Be that as it may, the pileipellis (or "peel") is distinct from the trama, the inner fleshy tissue of a mushroom or similar fruiting body, and also from the spore-bearing tissue layer, the hymenium.

References

  1. ^ Stevenson, Angus; Oxford Dictionaries; Soanes, Catherine (2008). Concise Oxford English dictionary. Oxford [Oxfordshire]: Oxford University Press. ISBN 0-19-954841-2. 
  2. ^ About the roundworm cuticle
  3. ^ 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]
  4. ^ "insect physiology" The McGraw-Hill Encyclopedia of Science of Technology, Vol. 9, p. 233 2007
  5. ^ Quere, D.; Surface chemistry. Fakir droplets, Nature Materials 2002, 1, 14.
  6. ^ Onda T., Shibuichi S., Satoh N., Tsujii K.; "Super-Water-Repellent Fractal Surfaces"; Langmuir, 1996, 12 (9), pp 2125–2127, DOI: 10.1021/la950418o
  7. ^ Von Baeyer, H. C., The lotus effect, The Sciences, 2000, January/February, 12
  8. ^ Jaeger, Edmund Carroll (1959). A source-book of biological names and terms. Springfield, Ill: Thomas. ISBN 0-398-06179-3. 

Wikimedia Foundation. 2010.

Synonyms:

Look at other dictionaries:

  • Cuticle — Cu ti*cle (k[=u] t[i^]*k l), n. [L. cuticula, dim. of cutis skin; akin to E. hide skin of an animal.] 1. (Anat.) The scarfskin or epidermis. See {Skin}. [1913 Webster] 2. (Bot.) The outermost skin or pellicle of a plant, found especially in… …   The Collaborative International Dictionary of English

  • cuticle — 1610s, from L. cuticula, dim. of cutis skin, from PIE *ku ti , from root * (s)keu to cover, conceal (Cf. Lith. kiautas husk, O.E. hyd skin, hide; see HIDE (Cf. hide) (n.1)). Specialized sense of s …   Etymology dictionary

  • cuticle — ► NOUN 1) dead skin at the base of a fingernail or toenail. 2) the epidermis of the body. 3) a protective layer covering the epidermis of a plant or invertebrate. DERIVATIVES cuticular adjective. ORIGIN from Latin cuticula little skin …   English terms dictionary

  • cuticle — [kyo͞ot′i kəl] n. [L cuticula, skin, dim. < cutis, skin < IE base * (s)keu t , to cover > HIDE2] 1. the outer layer of the skin; epidermis 2. hardened skin, such as accumulates at the base and sides of a fingernail 3. Bot. a delicate,… …   English World dictionary

  • cuticle — cuticular /kyooh tik yeuh leuhr/, adj. /kyooh ti keuhl/, n. 1. the nonliving epidermis that surrounds the edges of the fingernail or toenail. 2. the epidermis. 3. a superficial integument, membrane, or the like. 4. Also called cuticula. Zool. the …   Universalium

  • cuticle — UK [ˈkjuːtɪk(ə)l] / US [ˈkjutɪk(ə)l] noun [countable] Word forms cuticle : singular cuticle plural cuticles a layer of hard skin at the base of a nail on a finger or toe …   English dictionary

  • cuticle — noun Etymology: Latin cuticula, diminutive of cutis skin more at hide Date: 1615 1. an outer covering layer: as a. an external envelope (as of an insect) secreted usually by epidermal cells b. the outermost layer of an …   New Collegiate Dictionary

  • cuticle — См. cuticula …   Dictionary of invertebrate zoology

  • cuticle — noun /ˈkjuːtɪkəl/ a) The outermost layer of the skin of vertebrates; the epidermis. b) The strip of hardened skin at the base and sides of a fingernail or toenail. Syn: cuticula …   Wiktionary

  • cuticle — 1. An outer thin layer, usually horny in nature. SYN: cuticula (1). 2. The layer, chitinous in some invertebrates, which occurs on the surface of epithelial cells. 3. SYN: epidermis. [L. cuticula, dim. of cutis, skin] acquired c …   Medical dictionary


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.