Final answer:
The capillary endothelium is composed of simple squamous epithelium, which works in conjunction with the basement membrane and connective tissue in the tunica intima to maintain vessel integrity and function.
Step-by-step explanation:
The endothelium of capillaries is composed of simple squamous epithelium surrounded by loose connective tissue. The endothelium tissue, which lines vessels of the lymphatic and cardiovascular system, is a specialized type of epithelium that is essential for various physiological functions. It not only serves as a barrier between the blood and vessel walls but also plays a role in regulating capillary exchange, blood flow, and has involvement in the pathogenesis of cardiovascular disease through the production of chemicals such as endothelins.
Adjacent to the endothelium is the basement membrane or basal lamina, supporting the endothelial layer while providing both flexibility and permeability. This feature facilitates the transfer of materials and is critical for the functionality of blood vessels. Furthermore, the tunica intima, which houses the endothelium, also contains areolar connective tissue made predominantly of elastic fibers, adding flexibility to the vessels, and collagenous fibers, enhancing their strength.