Search results
Results from the WOW.Com Content Network
Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classical mechanism of cell secretion is via secretory portals at the plasma membrane called porosomes. [1]
Holocrine gland secretion is the most damaging (to the cell itself and not to the host which begot the cell) type of secretion, with merocrine secretion being the least damaging and apocrine secretion falling in between. Examples of holocrine glands include the sebaceous glands of the skin [2] [3] and the meibomian glands of the eyelid.
Merocrine is the most common manner of secretion. The gland releases its product and no part of the gland is lost or damaged (compare holocrine and apocrine). The term eccrine is specifically used to designate merocrine secretions from sweat glands (eccrine sweat glands), [1] although the term merocrine is often used interchangeably. [2] [3]
Merocrine – the cells of the gland excrete their substances by exocytosis into a duct; for example, pancreatic acinar cells, eccrine sweat glands [dubious – discuss], salivary glands, goblet cells, intestinal glands, tear glands, etc. Apocrine – the apical portion of the cytoplasm in the cell membrane, which contains the excretion, buds off.
Secretion is directly onto the apical surface. The glands in this group can be divided into three groups: Merocrine glands – cells secrete their substances by exocytosis. (e.g. mucous and serous glands; also called "eccrine", e.g. major sweat glands of humans, goblet cells, salivary gland, tear gland and intestinal glands)
Mucins (/ ˈ m juː s ɪ n /) are a family of high molecular weight, heavily glycosylated proteins (glycoconjugates) produced by epithelial tissues in most animals. [1] Mucins' key characteristic is their ability to form gels; therefore they are a key component in most gel-like secretions, serving functions from lubrication to cell signalling to forming chemical barriers. [1]
DNA cloning can be performed spontaneously by the cell for reproductive purposes. This is a form of asexual reproduction where an organism splits into fragments and then each of these fragments develop into mature, fully grown individuals that are clones of the original organism (See reproductive fragmentation). DNA cloning can also be ...
Light micrograph of a moss's leaf cells at 400X magnification. The following outline is provided as an overview of and topical guide to cell biology: . Cell biology – A branch of biology that includes study of cells regarding their physiological properties, structure, and function; the organelles they contain; interactions with their environment; and their life cycle, division, and death.