Tissues
Squamous Epithelial Tissue
Squamous epithelial tissues are thin and flat, scale-like in appearance, tend to have larger, elliptically-shaped nuclei.
Squamous epithelial tissue are used for filtration and diffusion. Due to their simple and thin construct, they allow for easy transmembrane movement.
Squamous epithelium is found in locations where rapid diffusion or filtration take place. In the kidney, simple squamous epithelium lines the Bowman’s capsule and the glomerulus. Filtration and diffusion is instrumental to the kidney's function, as the kidney filters about 180 litres of blood per day. Simple squamous epithelium also makes up the alveoli in the lungs, where rapid gas exchange occurs, as oxygen enters the bloodstream through alveolar blood vessels and carbon dioxide exits as waste.

Cuboidal Epithelial Tissue
These tissues are equally wide as they are tall, creating a square profile with a spherical nucleus at its centre.
Cuboidal tissues are able to provide a layer of protection from abrasion, foreign particles, invading bacteria and excessive water loss. In the kidney these distinct surfaces allow the simple cuboidal cells to facilitate in the absorption and transportation of substances that are filtered by the kidney. In the proximal convoluted tubules, the apical surface of the epithelium is lined with microvilli, creating a brush border, giving it a fuzzy appearance. The microvilli can aid in helping to transport material by “brushing” the molecules in the lumen of the tubules. On the surface of the ovaries, simple cuboidal that have the ability to rapidly divide and proliferate enables them to repair ovulatory defects that occur on the ovarian surface, especially during the time of ovulation.

Columnar Epithelial Tissue
Columnar epithelial tissues are longer than they are wide. Characteristically, their nuclei are found at the base