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

In biology, a lumen (from Latin lūmen, meaning "an opening"; plural lumina) is the inside space of a tubular structure, such as an artery or intestine.^[1] By extension, the term lumen is also used to describe the inside space of a cellular component or structure, such as the endoplasmic reticulum.

Examples of lumina[edit]

• 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 renal tubules and urinary collecting ducts
• The pathways of the female genital tract, starting with a single pathway of the vagina, splitting up in two lumina in the uterus, both of which continue through the fallopian tubes
• Within a cell, the inner membrane space of a thylakoid, endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria or microtubule.

Transluminal procedures[edit]

Transluminal procedures are procedures occurring through lumina, including:

• Natural orifice transluminal endoscopic surgery in the lumina of, for example the stomach, vagina, bladder or colon
• Percutaneous transluminal angioplasty in the lumina of blood vessels

See also[edit]

• Thylakoid lumen

References[edit]