For example, a pleural effusion is the collection of fluid between two layers of the pleura (the lung's covering).Endoscopy A procedure for looking inside body cavities, such as the esophagus (food pipe) or stomach.Erythema Redness of the skin.Erythrocyte The red blood cell that carries oxygen to the body cells and carbon dioxide away from body cells.Esophagitis Inflammation of the esophagus (food