Inner living of blood vessel is known as endothelium. Endothelium is made up of squamous epithelium. Squamous epithelium is a simple type of epithelium (i.e., single layered) in which cells are thin and this type of epithelium also known as pavement epithelium because of tiles like appearance.
Columnar epithelium cells are column like and nucleus is oval and basal e.g., Lining of stomach.
Ciliated epithelium is modified columnar epithelium, cilia present on free surface e.g., trachea.
Cuboidal epithelium cells are cube like and nucleus is rounded and central e.g., Lining of glands.