ACTUAL IMAGES OF EPITHELIAL TISSUES:
Simple cuboidal epithelium from a tubule (small tube) in the kidney. Notice the free surface, the cube shaped cells at the free surface, and the basement membrane:
Stratified cuboidal epithelium from a sweat gland. This type of tissue is relatively rare in the human body. This one is a little difficult to figure out, but you can still see the free surface, the cube shaped cells at the free surface, and the basement membrane:
Simple columnar epithelium from the gall bladder. Notice the free surface, the column shaped cells at the free surface, and the basement membrane:
Simple squamous epithelium from the lining of a blood vessel. Notice the free surfaces forming a lumen (space), the flattened cells at the free surfaces, and the basement membrane:
Stratified squamous epithelium from the palm of the hand. Notice the free surface, the many layers of flattened cells at the free surface, and the basement membrane:
Transitional epithelium from the urinary bladder. This one is more difficult to determine, but use the process of elimination to deduce the type from the characteristics. It has a free surface, so it is epithelial tissue, The cells are not shaped like cubes, columns, or scales, so it is a special case. It is not pseudostratified epithelium, because pseudostratified look like columnar. So, all you are left with is transitional epithelium:
