Bowman's membrane composition is described as which of the following?

Bowman's membrane composition is described as which of the following?

• A. Keratinocytes and collagen
• B. Collagen, laminin, nidogen, and perlucin
• C. Hematopoietic cells
• D. Elastic cartilage fibers

Answer: (B)

Bowman's membrane is an acellular extracellular matrix layer in the cornea that sits between the epithelial surface and the stroma. Its composition is primarily collagen, but it also includes basement-membrane–type proteins such as laminin and nidogen, along with a basement membrane proteoglycan like perlecan. This combination provides a dense, organized, cell-free scaffold that supports the overlying epithelium while anchoring to the stroma. The other options describe cell types or tissues that aren’t part of Bowman's membrane (keratinocytes are epithelial cells, hematopoietic cells are blood-derived, and elastic cartilage fibers belong to a different tissue type), so they don’t fit.

Bowman's membrane is an acellular extracellular matrix layer in the cornea that sits between the epithelial surface and the stroma. Its composition is primarily collagen, but it also includes basement-membrane–type proteins such as laminin and nidogen, along with a basement membrane proteoglycan like perlecan. This combination provides a dense, organized, cell-free scaffold that supports the overlying epithelium while anchoring to the stroma. The other options describe cell types or tissues that aren’t part of Bowman's membrane (keratinocytes are epithelial cells, hematopoietic cells are blood-derived, and elastic cartilage fibers belong to a different tissue type), so they don’t fit.