Exocrine gland
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| Exocrine gland | |
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| Human submaxillary gland. At the right is a group of mucous alveoli, at the left a group of serous alveoli. |
Exocrine glands are glands that secrete their products (enzymes) into ducts (duct glands). They are the counterparts to endocrine glands, which secrete their products (hormones) directly into the bloodstream (ductless glands) or release hormones (paracrines) affect only target cell near the release site by.
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[edit] Examples
Typical exocrine glands include sweat glands, salivary glands, mammary glands, stomach, liver and the pancreas. (Example of an endocrine gland is the adrenal gland, which is found on top of the kidneys and secretes the hormone adrenaline).
[edit] Types
There are multiple ways of classifying exocrine glands:
[edit] Structure
Exocrine glands contain a glandular portion and a duct portion, the structures of which can be used to classify the gland.
- The duct portion may be branched (called compound) or unbranched (called simple).
- The glandular portion may be tubular, acinar, or may be a mix of the two (called tubuloacinar). If the glandular portion branches, then the gland is called a branched gland.
[edit] Method of secretion
Exocrine glands are named apocrine gland, holocrine gland, or merocrine gland based on how their product is secreted.
- Apocrine glands - a portion of the plasma membrane buds off the cell, containing the secretion. Apocrine gland is often used to refer to the apocrine sweat glands which use merocrine secretion.
- Holocrine glands - the entire cell disintegrates to secrete its substance.
- Merocrine glands - cells secrete their substances by exocytosis. Also called "eccrine."
[edit] Product secreted
- Serous cells secrete proteins, often enzymes. Examples include chief cells and Paneth cells
- Mucous cells secrete mucus. Examples include Brunner's glands, esophageal glands, and pyloric glands
- Mixed glands secrete both protein and mucus. Examples include the salivary glands, although parotid gland is predominantly serous, the sublingual gland is predominantly mucous and the submandibular gland is both serous and mucous.
[edit] List of exocrine glands
Glands typically may be referred to by two or more means, though some terms are rarely seen. The names of the anatomists who first described them are often employed, as:
| name(s) | location | product | structure |
| apocrine sweat glands | skin | - | coiled tubular |
| Bartholin's glands, Tiedmann's glands, vulvovaginal glands | vulva, vagina | - | - |
| Bauhin's glands, anterior lingual glands | tongue, near tip | nonserous or mixed | - |
| Brunner's glands, duodenal glands | duodenum | mucous | compound tubular |
| bulbourethral glands, Cowper's glands, Mery's glands | penis, base | - | - |
| Ciaccio's glands, accessory lacrimal glands | eye | - | - |
| Cobelli's glands | esophagus, just above the cardia, in the mucosa | mucous | - |
| Duverney's gland | vagina, on either side | - | - |
| Ebner's glands | tongue | serous | - |
| eccrine sweat glands | skin | - | coiled tubular |
| esophageal glands | esophagus | mucous | racemose |
| exocrine pancreas | pancreas | serous | tubulo-acinar |
| Fränkel's glands | vocal cords, below the edge | - | - |
| gastric chief cell, Wasmann's glands | stomach | serous | - |
| glomus coccygeum, coccygeal gland, Luschka's gland or ganglion | coccyx, near the tip | - | - |
| goblet cells | digestive tract, respiratory tract | mucous | simple unicellular |
| Henle's glands | eyelids, in the conjuctiva | - | tubular |
| Huguier's glands | vagina | - | - |
| Krause's glands | conjunctiva, middle portion | mucous | - |
| Lieberkuhn's glands | intestines, surface of mucous membrane | - | simple tubular |
| Littré's glands, Morgagni's glands | spongy portion of the urethra | - | racemose |
| mammary gland | breast | - | compound tubulo-acinar |
| Meibomian gland | eyelids | sebaceous | - |
| Moll's glands | eyelids | - | - |
| Montgomery's glands | mammary areola | sebaceous | - |
| Naboth's glands | cervix and os uteri | mucous | - |
| olfactory glands, Bowman's glands | nose, olfactory region | - | - |
| Paneth cells | small intestine | serous | - |
| parathyroid glands, Gley's glands, Sandstroem's glands | thyroid, on surface | - | - |
| parotid gland | mouth | serous | tubulo-alveolar |
| Peyer's patches (or glands) | ileum, lymphatic glands | - | - |
| pyloric glands | stomach | mucous | simple branched tubular |
| sebaceous gland | skin | sebum | acinar - branched |
| Skene's glands, Guérin's glands | vagina | - | - |
| sublingual gland, Rivini's gland | mouth | mucus (primarily) | tubulo-alveolar |
| submandibular gland | mouth | mixed (M+S) | tubulo-alveolar |
| sudoriparous glands, Boerhaave's glands | skin | - | - |
| Sigmund's glands | epitrochlear lymph nodes | - | - |
| Suzanne's gland | mouth, beneath the alveolingual groove | mucous | - |
| Weber's glands | tongue | mucous | tubular |
| Glands of Zeis | eyelids, free edges | sebaceous | - |
[edit] See also
Prostate gland is an exocrine gland of the male mammalian reproductive system. It secretes a clear and basic fluid that constitutes 1/3 of the volume of semen.
[edit] Additional images
 Section of the human esophagus. Moderately magnified. |
 Dissection of a lactating breast. |
[edit] References
[edit] External links
- Diagram at mhhe.com
- gland at eMedicine Dictionary
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