In biology, anintegument is the tissue surrounding an organism's body or an organ within, such asskin, ahusk,shell, germ orrind.[1]
The term is derived fromintegumentum, which isLatin for "a covering". In a transferred, or figurative sense, it could mean acloak or adisguise.[2] In English, "integument" is a fairly modern word, its origin having been traced back to the early seventeenth century; and refers to a material or layer with which anything is enclosed, clothed, or covered in the sense of "clad" or "coated", as with a skin or husk.[1]
Inbotany, the term "integument" may be used as it is in zoology, referring to the covering of an organ. When the context indicates nothing to the contrary, the word commonly refers to an envelope covering the nucellus of theovule. The integument may consist of one layer (unitegmic) or two layers (bitegmic), each of which consisting of two or more layers of cells. The integument is perforated by a pore, the micropyle, through which the pollen tube can enter. It may develop into the testa, orseed coat.
The integument of an organ inzoology typically would comprise membranes of connective tissue such as those around a kidney or liver. In referring to the integument of an animal, the usual sense is its skin and its derivatives: theintegumentary system, where "integumentary" is a synonym of "cutaneous".
Inarthropods, the integument, or external "skin", consists of a single layer ofepithelialectoderm from which arises thecuticle,[3] an outer covering ofchitin, the rigidity of which varies as per its chemical composition. Themolting of this cuticle and growing of a larger one as part of their growth cycle is characteristic for arthropods, andecdysozoa in general.
Derivative terms include various adjectival forms such as integumentary (e.g. system), integumental (e.g. integumental glands, "peltate glands, the integument being raised like a bladder due to abundant secretion"[4]) and integumented (as opposed to bare).[5]
Other illustrative examples of usage occur in the following articles:
