Hypodermis


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hypodermis

[‚hī·pə′dər·mis]
(botany)
The outermost cell layer of the cortex of plants. Also known as exodermis.
(invertebrate zoology)
The layer of cells that underlies and secretes the cuticle in arthropods and some other invertebrates.

Hypodermis

 

in invertebrates (for example, crustaceans, arachnids, and insects), the thin layer of usually cylindrical epithelium lying immediately under the cuticle (which is formed by the secretory activity of the cells of the hypodermis). The various cutaneous glands and the tactile and olfactory hairs are located in the hypodermis. In nematodes, gastrotrichs, and several other worms, the hypodermis is a syncytium that secretes the cuticle.

In plants, the hypodermis is one or more layers of cells located under the epidermis of the stems, leaves, seeds, and fruits, or under the epiblem (piliferous layer) of the roots. The hypodermis is part of the primary cortex of stems, often consisting of cells with thickened walls, and may be classified by function as mechanical tissue. It is most characteristic of succulents. In leaves the hypodermis consists of one, or more often several, layers of cells of aquiferous tissue (for example, in a number of tropical plants) or of mechanical tissue (for example, in pines and sago palms). In the leaf the hypodermis is formed when the cells of the epidermis are divided by septa that are parallel to the surface of the leaf, such as in Ficus and Begonia, or from cells of the mesophyll of the leaf tissue lying under the epidermis, such as in some palms. In roots the outer layers of cells of the primary cortex are sometimes called the exodermis.

References in periodicals archive ?
Moreover, in mouse skin all three skin layers, i.e., epidermis, dermis, and hypodermis, are thinner and the epidermis does not deepen into the dermis with projections as it does in human skin.
Epidermis (Ep), hypodermis (Hi), exodermis (Ex), cortex (Co), endoderm (En), aerenchyma (Ae), metaxylem (MX), protoxylem (PX) phloem (Ph), pericycle (Pe) and parenchymatic marrow (Ma).
However, the adipose tissue, which corresponds to the hypodermis, did not suffer microscopic morphological changes (Figure 4(g)).
The hypodermis (not represented) is the innermost layer constituted mainly of adipose tissue.
The length density ([L.sub.v], the length of the vessels in the unit volume of the dermis and hypodermis) and the mean diameter of a vessel were estimated using a counting frame at a final magnification of 1380x and 130x to differentiate the capillaries (up to 10 [micro]m) and larger vessels (more than 10.1 micrometer), respectively.
That layer included the dermis and the hypodermis, and the MCs were found to populate this skin layer mostly.
According to anatomy distribution, WAT is subcategorized as visceral and subcutaneous fat tissue [5]; the former is located within the muscle walls of the abdomen covering internal organs, whereas the latter is located under the skin, specifically in the hypodermis [6].
Superficial dermal edema gives rise to wheals, while edema in the deep dermis, hypodermis and gastrointestinal tract results in angioedema.1 Wheals may occur alone in about 50% of cases, wheals with angioedema in 40%, and angioedema without wheals in 10%, both occurring simultaneously or separately.2
The anthocyanins are located in the vacuoles of cells in the hypodermis of skins (rarely in the pulp).
As the skin consists of the epidermis, dermis, hypodermis and other structures, such as vessels and nerve endings, with different radio-sensitivities, the consequent injury may be more superficial on the skin, but can also be expressed in deeper tissues.
The system targets microwave energy at the interface between the dermis and the hypodermis, "and we hypothesized that heat at this level in the skin may also have an important effect on the hair bulb," he said.
The skin is a complex structure with 3 layers; the epidermis, the dermis and the hypodermis.