Pathology (Histology) or biopsy is a tissue sample taken from a living person for the purpose of diagnosis and treatment. Cytology is another type of material that can be taken from a living person for pathological examination, which is the type of cells present in body fluids (pleural fluid, peritoneal fluid, urine), or naturally exfoliated cells from the covering epithelium (vaginal-cervical epithelium, bronchial epithelium).