New words
dermis – дерма connective – соединительный membrane – мембрана junction – соединение
to be characterized by – характеризоваться чем—то numerous – значительный
to increase – увеличивать
surface – поверхность area – площадь epidermal – эпидермальный thick – толстый skin – кожа
papillary – папиллярный devoid – происходить meshwork – ячеистая сеть coarse – грубый bundle – связка interwine – сплетаться bring – приносить to consists of – состоять из to contain – содержать collagen – коллагеновый adipocyte – жировая клетка
Cutaneous appendages are all derivatives of the epidermis.
Eccrine (merocrine) sweat glands are simple, coiled, tubular glands that are widely distributed over the body. Secretory portions are tightly coiled and consist of a single layer of columnar—like pyramidal cells.
Duct portions, composed of two cuboidal cell layers, are corkscrew—shaped and open onto the epidermal surface. These glands are important in thermal regulation.
Control of the eccrine glands is mainly by the innerva—tion of cholinergic fibers.
Apocrine sweat glands are also simple, coiled, tubular glands but are much less abundant in their distribution than eccrine glands. They can be found in the axillary, ar—eolar, and anal regions.
Secretory portions of these glands are composed of a single layer of cuboidal or columnar cells. They are larger and have a much wider luminal diameter than eccrine sweat glands. Myoepithelial cells surround the secretory cells within the basement membrane and contract to facilitate secretion.
Duct portions are similar to those of eccrine sweat glands but open onto hair follicles instead of onto the epidermal surfaces.
Functions of these glands in humans is not at all clear. Specialized apocrine glands in the ear canal (ceruminous glands) produce a secretion in conjunction with adjacent sebaceous glands to form the protective earwax (cerumen). Control of the apocrine glands is hormonal and via the innervation of adrenergic fibers. These glands do not begin to function until puberty.
Sebaceous glands are simple, branched holocrine aci—nar glands. They usually discharge their secretions onto the hair shaft within hair follicles. These glands are found in the dermis throught the skin, except on the palms and soles.