This slide shows a section from the kidney containing tubules that are made up of simple cuboidal epithelial cells.   Although such cells  are usually six-sided (cube shaped), they may appear square in side view and polygonal or hexagonal when viewed from the top.  Their spherical nuclei stain darkly and often give the layer an appearance of a string of beads.  This type of tissue is adapted for secretion and absorption.  In addition to forming the kidney tubules, simple cuboidal epithelium can be found covering the ovary and as a component of the ducts of many glands.