The kind of epithelium which forms the inner walls of blood vessels is
(1) cuboidal epithelium
(2) columnar epithelium
(3) celiated columnar epithelium
(4) squamous epithelium
(4) Simple squamous eepithelium consists of only one layer of flat, scale like cells usually polygonal cells, which are closely fitted together like the tiles of a mosaic. It is also known as pavement epithelium. It forms lining of blood vessels, lymph vessels, heart, peritoneum, pleura, Bowman's capsule etc.