Anatomy of an artery. The lumen is the space at the top.

Cross section of the gut. The lumen is the space in the middle.

A lumen (Lat. lūmen, an opening or light) (pl. lumina) in biology is the inside space of a tubular structure, such as an artery or intestine.^[1] By extension, a lumen can also be the inside space of a cellular component or structure, such as the endoplasmic reticulum.

For example:

• The interior of a vessel, such as the central space in an artery or vein through which blood flows.
• The interior of the gastrointestinal tract ^[2]
• The pathways of the bronchi in the lungs
• The interior of urinary collecting ducts
• The single pathway of the vagina
• Within a cell, the inner membrane space of a thylakoid, endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria or microtubule.

[edit] References

[edit] See also

• Thylakoid lumen

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