Duct (anatomy)

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For qualities of writing or speech, see Ductus (linguistics).
Duct
Dissected lactating breast gray1172.png
Dissection of a lactating breast.
1 - Fat
2 - Lactiferous duct/lobule
3 - Lobule
4 - Connective tissue
5 - Sinus of lactiferous duct
6 - Lactiferous duct
Gray1033.png
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.
Anatomical terminology

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

Types of ducts[edit]

Examples include:

Duct From To Carries
Lactiferous duct mammary gland nipple milk
Cystic duct gallbladder 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
Bartholin's ducts Bartholin's glands Vulva Bartholin's fluid

Duct system[edit]

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.

See also[edit]

see also K.D.Tripathy...by K.E.R

External links[edit]