Definition of guano. : a fertilizer containing the accumulated excrement of seabirds or bats; broadly : excrement especially of seabirds or bats.
Developmental Biology Online. Epithelial tissues come in three basic types: squamous, cuboidal and columnar. These three types of tissue are seen in either simple (only one cell layer thick) or stratified (many cells in thickness) arrangements.
Simple columnar epithelium is in the colon. This is the epithelium for most of the large intestine, but it abruptly changes to stratified squamous (non-keratinized) in the anal canal.