GENERAL HISTOLOGY

Detailed explanation-1: -The apical surface of epithelial cells, which lines the lumen of sac-and tube-shaped organs and the inner surfaces of the body cavities, forms the interface between the extracellular milieu and underlying tissues.

Detailed explanation-2: -An epithelium has a free surface, the apical surface, exposed to the outside, and an attached surface, the basal surface, resting on the underlying connective tissue.

Detailed explanation-3: -An apical surface is a surface that faces the lumen which is the inner cavity of an organ. An organ of structure also has a basal side which faces the basement membrane and is commonly in contact with connective tissue or muscle tissue below it.

Detailed explanation-4: -Epithelia are comprised almost entirely of cells. The apical surface faces the lumen (inside of a hollow organ) while the basal or basolateral surface is adjacent to the underlying tissue. In many epithelia, the apical surface is specialized.

Detailed explanation-5: -Ciliated columnar epithelium is composed of simple columnar epithelial cells with cilia on their apical surfaces. These epithelial cells are found in the lining of the fallopian tubes and parts of the respiratory system, where the beating of the cilia helps remove particulate matter.