Gland

A gland is an organ in an animal's body that synthesizes a substance such as hormones for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland).

Structure

Glands are organs that synthesizes a substance such as hormones for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Numerous glands exist throughout the human body.

Development

Every gland is formed by an ingrowth from an epithelial surface. This ingrowth may in the beginning possess a tubular structure, but in other instances glands may start as a solid column of cells which subsequently becomes tubulated.

As growth proceeds, the column of cells may divide or give off offshoots, in which case a compound gland is formed. In many glands, the number of branches is limited, in others (salivary, pancreas) a very large structure is finally formed by repeated growth and sub-division. As a rule, the branches do not unite with one another, but in one instance, the liver, this does occur when a reticulated compound gland is produced. In compound glands the more typical or secretory epithelium is found forming the terminal portion of each branch, and the uniting portions form ducts and are lined with a less modified type of epithelial cell.

Stuffing box

A stuffing box is an assembly which is used to house a gland seal. It is used to prevent leakage of fluid, such as water or steam, between sliding or turning parts of machine elements.

Gland

A gland is a general type of stuffing box, used to seal a rotating or reciprocating shaft against a fluid. The most common example is in the head of a tap (faucet) where the gland is usually packed with string which has been soaked in tallow or similar grease. The gland nut allows the packing material to be compressed to form a watertight seal and prevent water leaking up the shaft when the tap is turned on. The gland at the rotating shaft of a centrifugal pump may be packed in a similar way and graphite grease used to accommodate continuous operation. The linear seal around the piston rod of a double acting steam piston is also known as a gland, particularly in marine applications. Likewise the shaft of a handpump or wind pump is sealed with a gland where the shaft exits the borehole.

Gland (botany)

In plants, a gland is defined functionally as a plant structure which secretes one or more products. This may be located on or near the plant surface and secrete externally, or be internal to the plant and secrete into a canal or reservoir. Examples include glandular hairs, nectaries, hydathodes, and the resin canals in Pinus.

Notable examples

Salt glands of the mangrove

The salt glands of mangroves such as Acanthus, Aegiceras, Aegialitis and Avicennia are a distinctive multicellular trichome, a glandular hair found on the upper leaf surface and much more densely in the abaxial indumentum. On the upper leaf surface they are sunken in shallow pits, and on the lower surface they occur scattered among long nonglandular hairs composed of three or four cells. Development of the glands resembles that of the nonglandular hairs until the three-celled stage, when the short middle stalk cell appears. The salt gland continues to develop to produce two to four vacuolated cells at the level of the epidermis, the stalk cell with an almost completely cutinized wall, and at least eight terminal cells. The terminal cells have a thin, perforated cuticle which separates from the cell walls apically, leaving an enclosed cavity between them. The secreted salt evaporates and forms visible crystals.

MAF

MAF, an acronym or abbreviation, may refer to:

MAF (gene)

Transcription factor Maf also known as proto-oncogene c-Maf or V-maf musculoaponeurotic fibrosarcoma oncogene homolog is a transcription factor that in humans is encoded by the MAF gene.

Types

One type, MafA, also known as RIPE3b1, promotes pancreatic development, as well as insulin gene transcription.

Interactions

MAF has been shown to interact with:

References

Further reading

External links

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

MAF1

Repressor of RNA polymerase III transcription MAF1 homolog is a protein that in humans is encoded by the MAF1 gene.

This gene encodes a protein that is homologous to Maf1, a Saccharomyces cerevisiae protein which is highly conserved in eukaryotic cells. S. cerevisiae Maf1 is a negative effector of RNA polymerase III (Pol III). It responds to changes in the cellular environment and represses Pol III transcription. Biochemical studies identified the initiation factor TFIIIB as a target for Maf1-dependent repression.

References

Further reading

Lego

Lego (/ˈlɛɡoʊ/) is a line of plastic construction toys that are manufactured by The Lego Group, a privately held company based in Billund, Denmark. The company's flagship product, Lego, consists of colorful interlocking plastic bricks accompanying an array of gears, figurines called minifigures, and various other parts. Lego pieces can be assembled and connected in many ways, to construct objects such as vehicles, buildings, and working robots. Anything constructed can then be taken apart again, and the pieces used to make other objects.

The Lego Group began manufacturing the interlocking toy bricks in 1949. Since then a global Lego subculture has developed. Supporting movies, games, competitions, and six Legoland amusement parks have been developed under the brand. As of July 2015, 600 billion Lego parts had been produced.

In February 2015, Lego replaced Ferrari as Brand Finance's "world's most powerful brand".

History

The Lego Group began in the workshop of Ole Kirk Christiansen (1891–1958), a carpenter from Billund, Denmark, who began making wooden toys in 1932. In 1934, his company came to be called "Lego", derived from the Danish phrase leg godt, which means "play well". In 1947, Lego expanded to begin producing plastic toys. In 1949 Lego began producing, among other new products, an early version of the now familiar interlocking bricks, calling them "Automatic Binding Bricks". These bricks were based in part on the Kiddicraft Self-Locking Bricks, which were patented in the United Kingdom in 1939 and released in 1947. Lego modified the design of the Kiddicraft brick after examining a sample that they received from the supplier of an injection-molding machine that Lego purchased. The bricks, originally manufactured from cellulose acetate, were a development of the traditional stackable wooden blocks of the time.