Which statement is true about a lumen?

Which statement is true about a lumen?

• A. It is always filled with air.
• B. It is the hollow passage within a tubular organ or vessel.
• C. It is the thick muscular wall.
• D. It is a type of connective tissue.

Answer: (B)

The lumen is the inside hollow space of a tube-shaped structure. It’s the channel through which things flow—blood in vessels, digested material in the intestines, air in airways—so it isn’t limited to always being air-filled. The thick muscular wall surrounds this space, but the lumen itself is the hollow passage, not the wall. It isn’t a type of connective tissue. So the true statement is that the lumen is the hollow passage within a tubular organ or vessel.

The lumen is the inside hollow space of a tube-shaped structure. It’s the channel through which things flow—blood in vessels, digested material in the intestines, air in airways—so it isn’t limited to always being air-filled. The thick muscular wall surrounds this space, but the lumen itself is the hollow passage, not the wall. It isn’t a type of connective tissue. So the true statement is that the lumen is the hollow passage within a tubular organ or vessel.