pineal gland


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Related to pineal gland: melatonin

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 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 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 (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.
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
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.

pin·e·al bod·y

[TA]
a small, unpaired, flattened body, shaped somewhat like a pinecone, attached at its anterior pole to the region of the posterior and habenular commissures and lying in the depression between the two superior colliculi below the splenium of the corpus callosum; it is a glandular structure, composed of follicles containing epithelioid cells and lime concretions called brain sand; despite its attachment to the brain, it appears to receive nerve fibers exclusively from the peripheral autonomic nervous system. It produces melatonin and serotonin.

pineal gland

n.
A small, cone-shaped organ in the brain of most vertebrates that secretes the hormone melatonin. Also called epiphysis, pineal body, pineal organ.

pineal gland

pin·e·al gland

(pin'ē-ăl gland) [TA]
A small, unpaired, flattened body shaped something like a pinecone; attached at its anterior pole to the region of the posterior and habenular commissures, and lying in the depression between the two superior colliculi below the splenium of the corpus callosum. It is a glandular structure, composed of follicles containing epitheloid cells and lime concentrations called 'brain sand'; despite its attachment to the brain, it appears to receive nerve fibers exclusively from the peripheral autonomic nervous system. It produces melanin.
Synonym(s): corpus pineale [TA] , pineal body.

pineal gland

A tiny, cone-shaped structure within the brain, whose sole function appears to be the secretion of the hormone melatonin. The amount of hormone secreted varies over a 24-hour cycle, being greatest at night. Control over this secretion is possibly exerted through nerve pathways from the retina in the eye; a high light level seems to inhibit secretion. The exact function of melatonin is not understood, but it may help to synchronize circadian (24-hour) or other biorhythms. The pineal gland is situated deep within the brain, just below the back part of the corpus callosum (the band of nerve fibres that connects the two halves of the cerebrum). In rare cases, it is the site of a tumour.

pineal gland

see PINEAL BODY.

pineal

1. shaped like a pine cone.
2. pertaining to the pineal body.

pineal body, pineal gland
a small, conical endocrine gland attached by a stalk to the dorsal wall of the third ventricle of the cerebrum. In certain amphibians and reptiles the gland functions as a light receptor. In most mammals, including humans, it appears to be the major or unique site of melatonin biosynthesis. The effect of melatonin on the body and the exact function of the pineal body remain uncertain. There is an increasing body of evidence that the pineal body is inhibitory to the gonads and that it is the principal mechanism in the known effect of environmental illumination on estrous cycles. It is proposed that the retina perceives the changes in light intensity and stimulates the pineal gland via the sympathetic nervous system.
pineal extract
pineal eye
in lower vertebrates the pineal body is a third or pineal eye.
pineal gland
see pineal body (above).
References in periodicals archive ?
A greater percentage of those with a mutation expressed in the pineal gland considered themselves sleepy according to PSQI, compared to those who carried a mutation in the retina only; however, the mean score of both groups was the same (see Table 5).
We still don't know to what extent decreased melatonin production is caused by fluoride in the pineal gland.
Through its secretion of melatonin, the pineal gland acts as the body's central clock, telling the brain and other organs when it's time to be active and when it's time to rest.
In dark situations, sympathetic input from the superior sympathetic ganglion at the pineal gland leads to increased melatonin production.
The habenular commisure, anterior to the pineal gland, is another location for physiologic calcifications.
Melatonin, the chief secretory product of the pineal gland, has many physiological functions, including regulation of the circadian rhythm (24).
Others cover the mechanism of intracellular transport and secretion of the pituitary hormone, the connection between the neuroendocrine and immune systems, leptin levels, craving, and cocaine abuse-dependence, the effects of steroids on the brain, the structure and functions of the pineal gland, the role of melatonin, and pain and neurosecretory regulation, among other topics.
the brain and disrupt the function of the pineal gland, which produces the sleep hormone melatonin.
For example, if you deprive yourself of the dark cycle with the use of bright fluorescent lighting at night, you decrease the amount of time your pineal gland has to produce melatonin, the powerful antioxidant that keeps sleep disorders at bay and the natural behavior of many bodily functions on course.
corn), a hormone naturally released by your body's pineal gland after sunset to promote sleepiness.
2000), the present study was conducted to establish the relationship between adrenal cortex and pineal gland under thermal-stress.
Melatonin is released from the brain's pea-sized pineal gland at night.