sebaceous gland

(səbā`shəs), gland in the skinskin,
the flexible tissue (integument) enclosing the body of vertebrate animals. In humans and other mammals, the skin operates a complex organ of numerous structures (sometimes called the integumentary system) serving vital protective and metabolic functions.
..... Click the link for more information. of mammals that secretes an oily substance called sebum. In humans, sebaceous glands are primarily found in association with hairhair,
slender threadlike outgrowth from the skin of mammals. In some animals hair grows in dense profusion and is called fur or wool. Although all mammals show some indication of hair formation, dense hair is more common among species located in colder climates and has the
..... Click the link for more information. follicles but also occur in hairless areas of the skin, except for the palms of the hand and soles of the feet. Sebum is a mixture of fat and the debris of dead fat-producing cells. These cells are constantly replaced by new growth at the base of the glands. Generally the sebum is deposited on the hairs inside the follicles and is brought up to the surface of the skin along the hair shaft. In hairless areas, the sebum surfaces through ducts. Sebum lubricates and protects the hair and skin and prevents drying and irritation of membranes. Sebum may collect excessively as a result of poor hygiene, a diet rich in fats, or accelerated glandular activity, especially during adolescence. Excessive secretions of sebum may be related to acneacne,
common inflammatory disease of the hair follicles and sebaceous glands characterized by blackheads, whiteheads, pustules, nodules and, in the more severe forms, by cysts and scarring. The lesions appear on the face, neck, back, chest, and arms.
..... Click the link for more information. , certain forms of baldnessbaldness,
thinning or loss of hair as a result of illness, functional disorder, or hereditary disposition; also known as alopecia. Male pattern baldness, a genetic trait, is the most common cause of baldness among white males.
..... Click the link for more information. , and other skin disorders.

Sebaceous Gland

in humans and other mammals, a simple acinous gland with a short excretory duct and a branched end section that is located in the skin between the papillary and reticular layers of the dermis and that secretes cutaneus sebum. Sebaceous glands are distributed over the entire skin, except over the palmar and plantar surfaces.

Generally, sebaceous glands are connected to hairs: the excretory duct opens into the narrow fissure between the root and epithelial sheath of a hair. However, some glands, for example those on the lips, labia minora pudendi, nipples and nipple areas, and head and foreskin of the penis, open directly onto the body surface. The excretory duct is lined with stratified squamous epithelium, which on one side directly becomes the malpighian layer of the hair’s external root sheath and on the other becomes the wall of the alveolus. The latter consists of cells that are only slightly differentiated and capable of mitosis. These cells are rich in RNA and various enzymes and are especially concentrated near the excretory duct. The alveolus is filled with cells that contain fat droplets. Deep in the alveolus, cells undergo fatty degeneration, and as a result, their fat content increases and their nucleus wrinkles and decomposes.

Cutaneus sebum is formed from the remains of destroyed cells and fat. It serves as a fatty lubricant for the hair and skin surface and makes the skin elastic and impermeable to water, chemical substances, and certain microorganisms. The secretion of cutaneous sebum is promoted by the contraction of the skin musculature. The musk glands of certain reptiles and mammals and the uropygial glands of birds are sebaceous glands. In humans, the most common diseases of the sebaceous glands are atheroma, acne, and seborrhea.

E. S. KIRPICHNIKOVA

sebaceous gland

[si′bā·shəs ′gland] (physiology) A gland, arising in association with a hair follicle, which produces and liberates sebum.

sebaceous gland

gland

[gland] an aggregation of cells specialized to secrete or excrete materials not related to their ordinary metabolic needs. Glands are divided into two main groups, endocrine and exocrine. adj., adj glan´dular.
The endocrine glands, or ductless glands, discharge their secretions (hormones) directly into the blood; they include the adrenal, pituitary, thyroid, and parathyroid glands, the islands of Langerhans in the pancreas, the gonads, the thymus, and the pineal body. The glands" >exocrine glands discharge through ducts opening on an external or internal surface of the body; they include the salivary, sebaceous, and sweat glands, the liver, the gastric glands, the pancreas, the intestinal, mammary, and lacrimal glands, and the prostate. The lymph nodes" >lymph nodes are sometimes called lymph glands but are not glands in the usual sense.

Classification of glands according to mode of secretion. From Applegate, 2000.acinous gland one made up of one or more acini" >acini (oval or spherical sacs).adrenal gland see adrenal gland.apocrine gland one whose discharged secretion contains part of the secreting cells.areolar g's Montgomery's glands.axillary g's lymph nodes in the axilla.Bartholin g's two small mucus-secreting glands, one on each side in the lower pole of the labium majus and connected to the surface by a duct lined with transitional cells, which opens just external to the hymenal ring. Their exact function is not clear but they are believed to secrete mucus to moisten the vestibule during sexual excitement. Called also major vestibular glands.Bowman's g's olfactory glands.bronchial g's seromucous glands in the mucosa and submucosa of the bronchial walls.Brunner's g's glands in the submucosa of the duodenum that secrete intestinal juice; called also duodenal glands.buccal g's seromucous glands on the inner surface of the cheeks; called also genal glands.bulbocavernous g's (bulbourethral g's) two glands embedded in the substance of the sphincter of the male urethra, posterior to the membranous part of the urethra; their secretion lubricates the urethra; called also Cowper's glands.cardiac g's mucus-secreting glands of the cardiac part (cardia) of the stomach.celiac g's lymph nodes anterior to the abdominal aorta.ceruminous g's cerumin-secreting glands in the skin of the external auditory canal.cervical g's 1. the lymph nodes of the neck.2. compound clefts in the wall of the uterine cervix.ciliary g's sweat glands that have become arrested in their development, situated at the edges of the eyelids; called also Moll's glands.circumanal g's specialized sweat and sebaceous glands around the anus; called also Gay's glands.Cobelli's g's mucous glands in the esophageal mucosa just above the cardia.coccygeal gland glomus coccygeum.compound gland one made up of a number of smaller units whose excretory ducts combine to form ducts of progressively higher order.Cowper's g's bulbourethral glands.ductless g's endocrine glands.duodenal g's Brunner's glands.Ebner's g's serous glands at the back of the tongue near the taste buds.eccrine gland one of the ordinary or simple sweat glands, which are of the merocrine type.endocrine g's see endocrine glands.exocrine g's glands that discharge their secretions through ducts opening on internal or external surfaces of the body; see gland" >gland.fundic g's (fundus g's) numerous tubular glands in the mucosa of the fundus and body of the stomach that contain the cells that produce acid and pepsin.gastric g's the secreting glands of the stomach, including the fundic, cardiac, and pyloric glands.Gay's g's circumanal glands.genal g's buccal glands.glossopalatine g's mucous glands at the posterior end of the smaller sublingual glands.haversian g's synovial villi.holocrine gland one whose discharged secretion contains the entire secreting cells.intestinal g's straight tubular glands in the mucous membrane of the intestines, in the small intestine opening between the bases of the villi, and containing argentaffin cells. Called also crypts or glands of Lieberkühn.jugular gland a lymph node behind the clavicular insertion of the sternocleidomastoid muscle.Krause's gland an accessory lacrimal gland deep in the conjunctival connective tissue, mainly near the upper fornix.lacrimal g's the glands that secrete tears; see also lacrimal apparatus.g's of Lieberkühn intestinal glands.lingual g's the seromucous glands on the surface of the tongue.lingual g's, anterior seromucous glands near the apex of the tongue.Littre's g's 1. preputial glands.2. the male urethral glands.lymph gland lymph node.major vestibular g's Bartholin glands.mammary gland a specialized gland of the skin of female mammals, which secretes milk for the nourishment of their young; it exists in a rudimentary state in the male. See also breast.meibomian g's sebaceous follicles between the cartilage and conjunctiva of the eyelids. Called also tarsal glands.merocrine gland one whose discharged secretion contains no part of the secreting cells.mixed g's 1. seromucous glands.2. glands that have both exocrine and endocrine portions.Moll's g's ciliary glands.Montgomery's g's sebaceous glands in the mammary areola; called also areolar glands.mucous g's glands that secrete mucus.olfactory g's small mucous glands in the olfactory mucosa; called also Bowman's glands.parathyroid g's see parathyroid glands.parotid g's see parotid glands.peptic g's gastric glands that secrete pepsin.pineal gland pineal body.pituitary gland see pituitary gland.preputial g's small sebaceous glands of the corona of the penis and the inner surface of the prepuce, which secrete smegma; called also Littre's glands and Tyson's glands.prostate gland prostate.pyloric g's the mucin-secreting glands of the pyloric part of the stomach.salivary g's see salivary glands.sebaceous gland a type of holocrine gland of the corium that secretes an oily material (sebum) into the hair follicles.

Glands: The relationship of the hair follicle, eccrine and apocrine sweat glands and sebaceous glands. From Copstead, 1995.sentinel gland an enlarged lymph node, considered to be pathognomonic of some pathologic condition elsewhere.seromucous g's glands that are both serous and mucous.serous gland a gland that secretes a watery albuminous material, commonly but not always containing enzymes.sex gland (sexual gland) gonad.simple gland one with a nonbranching duct.Skene's g's the largest of the female urethral glands, which open into the urethral orifice; they are regarded as homologous with the prostate. Called also paraurethral ducts.solitary g's solitary follicles.sublingual gland a salivary gland on either side under the tongue.submandibular gland (submaxillary gland) a salivary gland on the inner side of each ramus of the mandible.sudoriferous gland (sudoriparous gland) sweat gland.suprarenal gland adrenal gland.sweat gland see sweat gland.target gland any gland affected by a secretion or other stimulus from another gland, such as those affected by the secretions of the pituitary gland.tarsal g's meibomian glands.thymus gland thymus.thyroid gland see thyroid gland.tubular gland any gland made up of or containing a tubule or tubules.Tyson's g's preputial glands.unicellular gland a single cell that functions as a gland, e.g., a goblet cell.urethral g's mucous glands in the wall of the urethra; in the male, called also Littre's glands.uterine g's simple tubular glands found throughout the thickness and extent of the endometrium; they become enlarged during the premenstrual period.vesical g's mucous glands sometimes found in the wall of the urinary bladder, especially in the area of the trigone.vulvovaginal g's Bartholin's glands.Waldeyer's g's glands in the attached edge of the eyelid.Weber's g's the tubular mucous glands of the tongue.

sebaceous gland

n. Any of various glands in the dermis of the skin that open into a hair follicle and produce and secrete sebum.

sebaceous gland

one of many glands occurring in the skin, that secretes oil or sebum into the hair follicles in mammals.This maintains an oily coating to the hair and contributes to its waterproofing.Secretions from sebaceous glands are the result of cell destruction.

sebaceous gland

sebaceous gland

seba′ceous gland`

se·ba·ceous gland

sebaceous gland

sebaceous gland

sebaceous gland

Sebaceous Gland

sebaceous gland

sebaceous gland

gland

sebaceous gland

sebaceous gland

sebaceous gland

Synonyms for sebaceous gland

noun a cutaneous gland that secretes sebum (usually into a hair follicle) for lubricating hair and skin

Synonyms

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