gland

1. a cell or organ in man and other animals that synthesizes chemical substances and secretes them for the body to use or eliminate, either through a duct (see exocrine gland) or directly into the bloodstream (see endocrine gland)

2. a structure, such as a lymph node, that resembles a gland in form

3. a cell or organ in plants that synthesizes and secretes a particular substance

gland

Engineering a device that prevents leakage of fluid along a rotating shaft or reciprocating rod passing through a boundary between areas of high and low pressure. It often consists of a flanged metal sleeve bedding into a stuffing box

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

Gland

A structure which produces a substance or substances essential and vital to the existence of the organism and species. Glands are classified according to (1) the nature of the product; (2) the structure; (3) the manner by which the secretion is delivered to the area of use; and (4) the manner of cell activity in forming secretion. A commonly used scheme for the classification of glands follows.

I. Morphological criteria
A. Unicellular (mucous goblet cells)
B. Multicellular
1. Sheets of gland cells (choroid plexus)
2. Restricted nests of gland cells (urethral glands)
3. Invaginations of varying degrees of complexity
a. Simple or branched tubular (intestinal and gas-tric glands)—no duct interposed between surface and glandular portion
b. Simple coiled (sweat gland)—duct interposed between glandular portion and surface
c. Simple, branched, acinous (sebaceous gland)—glandular portion spherical or ovoid, connected to surface by duct
d. Compound, tubular glands (gastric cardia, renal tubules)—branched ducts between surface and glandular portion
e. Compound tubular-acinous glands (pancreas, parotid gland)—branched ducts, terminating in secretory portion which may be tubular or acinar
II. Mode of secretion
A. Exocrine—the secretion is passed directly or by ducts to the exterior surface (sweat glands) or to another surface which is continuous with the external surface (intestinal glands, liver, pancreas, submaxillary gland)
B. Endocrine—the secretion is passed into adjacent tissue or area and then into the bloodstream directly or by way of the lymphatics; these organs are usually circumscribed, highly vascularized, and usually have no connection to an external surface (adrenal, thyroid, parathyroid, islets of Langerhans, parts of the ovary and testis, anterior lobe of the hypophysis, intermediate lobe of the hypophysis, groups of nerve cells of the hypothalamus, and the neural portion of the hypophysis)
C. Mixed exocrine and endocrine glands (liver, testis, pancreas)
D. Cytocrine—passage of a secretion from one cell directly to another (melanin granules from melanocytes in the connective tissue of the skin to epithelial cells of the skin)
III. Nature of secretion
A. Cytogenous (testis, perhaps spleen, lymph node, and bone marrow)—gland “secretes” cells
B. Acellular (intestinal glands, pancreas, parotid gland)—gland secretes noncellular product
IV. Cytological changes of glandular portion during secretion
A. Merocrine (sweat glands, choroid plexus)—no loss of cytoplasm
B. Holocrine (sebaceous glands)—gland cells undergo dissolution and are entirely extruded, together with the secretory product
C. Apocrine (mammary gland, axillary sweat gland)—only part of the cytoplasm is extruded with the secretory product
V. Chemical nature of the product
A. Mucous goblet cells (submaxillary glands, urethral glands)—the secretion contains mucin
B. Serous (parotid gland, pancreas)—the secretion does not contain mucin

gland

[gland]

(anatomy)

A structure which produces a substance essential and vital to the existence of the organism.

(engineering)

A device for preventing leakage at a machine joint, as where a shaft emerges from a vessel containing a pressurized fluid.

A movable part used in a stuffing box to compress the packing.

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References in periodicals archive

Other tumors of ceruminous gland origin, includes ceruminous pleomorphic adenoma, Ceruminous syringocystadenoma papilliferum and ceruminous adenocarcinoma and tumors seen around this anatomical site comprise of neuroendocrine adenoma of the middle ear, parotid pleomorphic adenoma, meningioma and paraganglioma.

On electron microscopy, ceruminous gland adenoma showed apocrine caps, microvilli, cell junctions, secretory granules, vacuoles, lipid droplets and siderosomes, the characteristic ultrastructural features of apocrine glands.

CONCLUSION: Ceruminous adenomas are rare benign glandular tumor of external auditory canal of ceruminous gland origin.

Ceruminous adenoma of external auditory canal in a young adult: a rare case report

Ceruminous gland adenomas are rare neoplastic skin disease of ear of unknown etiology (Moisan and Watson, 1996).

Goldschmidt and Hendrick (2002) reported that ceruminous gland adenoma had neoplastic cells arranged in acini and becomes cystic contains copper coloured fluids is in agreement with present case.

Surgical Management of Ceruminous Adenoma in a Dog

But perhaps this should not be surprising because both the ceruminous glands and the breasts are exocrine glands.

While doing research at the University of Toronto, we hypothesized that cerumen impaction is not a result of overproduction in the ceruminous glands, but a failure of individual corneocytes in the stratum corneum to separate.

Update on cerumen and ceruminolytics