cortex

n., pl., -ti·ces (-tĭ-sēz'), or -tex·es.

1. Anatomy.
   1. The outer layer of an internal organ or body structure, as of the kidney or adrenal gland.
   2. The outer layer of gray matter that covers the surface of the cerebral hemisphere.
2. Botany. The region of tissue in a root or stem lying between the epidermis and the vascular tissue.
3. An external layer, such as bark or rind.

[Latin, bark.]

The mass of primary tissue in roots and stems extending inward from the epidermis to the phloem. The cortex may consist of one or a combination of three major tissues: parenchyma, collenchyma, and sclerenchyma. In roots the cortex almost always consists of parenchyma, and is bounded, more or less distinctly, by the hypodermis (exodermis) on the periphery and by the endodermis on the inside.

Cortical parenchyma is composed of loosely arranged thin-walled living cells. Prominent intercellular spaces usually occur in this tissue. In stems the cells of the outer parenchyma may appear green due to the presence of chloroplasts in the cells. This green tissue is sometimes called chlorenchyma, and it is probable that photosynthesis takes place in it.

In some species the cells of the outer cortex are modified in aerial stems by deposition of hemicellulose as an additional wall substance, especially in the corners or angles of the cells. This tissue is called collenchyma, and the thickening of the cell walls gives mechanical support to the shoot.

The cortex makes up a considerable proportion of the volume of the root, particularly in young roots, where it functions in the transport of water and ions from the epidermis to the vascular (xylem and phloem) tissues. In older roots it functions primarily as a storage tissue.

In addition to being supportive and protective, the cortex functions in the synthesis and localization of many chemical substances; it is one of the most fundamental storage tissues in the plant. The kinds of cortical cells specialized with regard to storage and synthesis are numerous.

Because the living protoplasts of the cortex are so highly specialized, patterns and gradients of many substances occur within the cortex, including starch, tannins, glucosides, organic acids, crystals of many kinds, and alkaloids. Oil cavities, resin ducts, and laticifers (latex ducts) are also common in the midcortex of many plants.

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The primary plant tissue between the vascular system and the epidermis of the stem and the root.

Pl. cortices [L.] an outer layer, as the bark of the trunk or root of a tree, or the outer layer of an organ or other structure, as distinguished from its inner substance.

• adrenal c. — the outer, firm layer comprising the larger part of the adrenal gland; it secretes a number of hormones. See corticosteroid, aldosterone, mineralocorticoid, glucocorticoid.
• cerebellar c. — the superficial gray matter of the cerebellum.
• cerebral c., c. cerebri — the convoluted layer of gray matter covering each cerebral hemisphere. See also cerebral cortex.
• renal c. — the smooth-textured outer layer of the kidney, composed mainly of renal corpuscles and convoluted tubules, extending in columns between the pyramids.

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Dansk (Danish)
n. - bark, cortex, vævslag lige under yderbark

Nederlands (Dutch)
schors, cortex

Français (French)
n. - (Anat, Bot) cortex

Deutsch (German)
n. - (Bot.) Rinde, Kortex

Ελληνική (Greek)
n. - (ανατ., φυτολ.) φλοιός, φλούδα

Italiano (Italian)
corteccia

Português (Portuguese)
n. - córtex (m) (Bot.) (Zool.)

Русский (Russian)
кора

Español (Spanish)
n. - corteza

Svenska (Swedish)
n. - bark (bot. el anat.)

中文（简体）(Chinese (Simplified))
皮层, 树皮

中文（繁體）(Chinese (Traditional))
n. - 皮層, 樹皮

한국어 (Korean)
n. - 외피, 대뇌 피질, 나무껍질

日本語 (Japanese)
n. - 皮質, 皮層, 外皮, 樹皮

العربيه (Arabic)
‏(الاسم) الغلاف الخارجي أو الطبقه الخارجيه لأعضاء الجسم, قشرة‏

עברית (Hebrew)
n. - ‮קליפה‬

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