Lymphology Association of North America (LANA) Practice Exam

Which components make up the structure of a lymph capillary?

1. Flat endothelial and Langerhans cells

2. Flat endothelial cells with anchoring filaments

3. Smooth muscle cells and bicuspid valves

4. Edged endothelial cells with anchoring filaments

The correct answer is: Flat endothelial cells with anchoring filaments

The structure of a lymph capillary primarily consists of flat endothelial cells that form the walls of the capillaries. These endothelial cells are specialized to allow for the permeability required in the lymphatic system, which is essential for the collection of interstitial fluid, proteins, and other materials from tissues. Additionally, anchoring filaments are present, which play a crucial role in maintaining the integrity and functionality of the lymph capillaries. These filaments connect the endothelial cells to the surrounding tissues, helping to keep the capillaries open and functional, especially in response to changes in pressure when interstitial fluid accumulates. This unique structural design allows lymph capillaries to easily absorb excess interstitial fluid and proteins, ultimately aiding in the return of lymph back to the circulatory system. The presence of anchoring filaments supports the capillaries during fluid overload situations, ensuring that they do not collapse or lose their ability to collect lymph. The other options either inaccurately describe the components of lymph capillaries or include structures not associated with lymphatic capillaries, such as smooth muscle cells or bicuspid valves, which are not found in the capillaries but rather in larger lymphatic vessels and veins.