Duct (anatomy)

Duct
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.
Identifiers
FMA 30320
Anatomical terminology

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

Types of ducts

Examples include:

DuctFromToCarries
Lactiferous ductmammary glandnipplemilk
Cystic ductgallbladdercommon bile ductbile
Common hepatic ductlivercommon bile ductbile
Common bile ductcommon hepatic duct and cystic ductpancreatic ductbile
Pancreatic ductpancreashepatopancreatic ampullabile and pancreatic enzymes
Ejaculatory ductvas deferensurethrasemen
Parotid ductparotid glandmouthsaliva
Submandibular ductsubmandibular glandmouthsaliva
Major sublingual ductsublingual glandmouthsaliva
Bartholin's ductsBartholin's glandsvulvaBartholin's fluid
Cerebral aqueductfourth ventriclethird ventriclecerebrospinal fluid

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 ductEpitheliumSurroundings
intralobular ductsimple cuboidalparenchyma
interlobular ductsimple columnarconnective tissue
interlobar ductstratified columnarconnective 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.

See also

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