Duct (anatomy)

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Duct (anatomy)
Dissection of a lactating breast.
1 - Fat
2 - Lactiferous duct/lobule
3 - Lobule
4 - Connective tissue
5 - Sinus of lactiferous duct
6 - Lactiferous duct
Section of the human esophagus. Moderately magnified. The section is transverse and from near the middle of the gullet.
a. Fibrous covering.
b. Divided fibers of longitudinal muscular coat.
c. Transverse muscular fibers.
d. Submucous or areolar layer.
e. Muscularis mucosae.
f. Mucous membrane, with vessels and part of a lymphoid nodule.
g. Stratified epithelial lining.
h. Mucous gland.
i. Gland duct.
m’. Striated muscular fibers cut across.

In in anatomy and physiology, a duct is a circumscribed channel leading from an exocrine gland or organ.

Contents

[edit] Types of ducts

Examples include:

Duct From To Carries
Lactiferous duct mammary gland nipple milk
Cystic duct spleen common bile duct bile
Common hepatic duct liver common bile duct bile
Common bile duct common hepatic duct and cystic duct pancreatic duct bile
Pancreatic duct pancreas hepatopancreatic ampulla bile and pancreatic enzymes
Ejaculatory duct vas deferens urethra semen
Parotid duct parotid gland mouth saliva
Submaxillary duct submaxillary gland mouth saliva
Major sublingual duct sublingual gland mouth saliva

[edit] Duct system

As ducts travel from the acinus which generates the fluid to the target, the ducts become larger and the epithelium becomes thicker. The parts of the system are classified as follows:

Type of duct Epithelium Surroundings
intralobular duct simple cuboidal parenchyma
interlobular duct simple columnar connective tissue
interlobar duct stratified columnar connective tissue

Some sources consider "lobar" ducts to be the same as "interlobar ducts", while others consider lobar ducts to be larger and more distal from the acinus. For sources that make the distinction, the interlobar ducts are more likely to classified with simple columnar epithelium (or pseudostratified epithelium), reserving the stratified columnar for the lobar ducts.

[edit] Additional images

Section of submaxillary gland of kitten. Duct semidiagrammatic. X 200.

Section of portion of mamma.

[edit] External links

 This anatomy article is a stub. You can help Wikipedia by expanding it.
v • d • e
Glands (Endocrine, Exocrine)
mechanism (Merocrine, Apocrine, Holocrine) shape (Tubular gland, Alveolar gland) secretion (Serous glands, Mucous glands, Serous demilune)

Ducts: Interlobar duct, Interlobular duct, Intralobular duct (Striated duct, Intercalated duct), Acinus
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