Question

multiple choice question
which describes lymphatic capillaries?

closed - ended vessels consisting of endothelial cells adhered to a complete basal lamina
closed - ended vessels consisting of loosely overlapping endothelial cells
open - ended vessels consisting of endothelial cells connected by tight junctions
open - ended vessels consisting of loosely overlapping endothelial cells

Explanation:

To determine the correct description of lymphatic capillaries, we recall their structural features: Lymphatic capillaries are closed - ended (they don't have an open end like some other vessels) and are made up of endothelial cells that overlap loosely. This loose overlapping allows for the uptake of interstitial fluid, proteins, and other substances.

• The first option is incorrect because lymphatic capillaries do not have a complete basal lamina (the basal lamina is incomplete or absent in some areas).
• The third and fourth options are incorrect because lymphatic capillaries are closed - ended, not open - ended, and they do not have tight junctions (tight junctions would prevent the uptake of substances from the interstitial space).
• The second option correctly states that lymphatic capillaries are closed - ended vessels with loosely overlapping endothelial cells.

Answer:

B. Closed - ended vessels consisting of loosely overlapping endothelial cells