A dominant gene will always be expressed when present, such as in the homozygous dominant genotype (RR), or heterozygous genotype (Rr). A recessive allele is only expressed wh â¦ en the genotype is homozygous recessive (rr).
(Lung alveoli, in contrast, are lined by very thin simple squamous epithelium .). Pseudostratified respiratory epithelium consists primarily of columnar ciliated cells. Ciliary beating sweeps mucus and the dust it carries up the bronchi and trachea toward the pharynx, where it can be swallowed.
The principle structural types are simple and stratified. Simple epithelium has only one layer of cells, while stratified epithelium has two or more layers. The form and function classifications of epithelial tissue are cuboidal, squamous, and columnar. rare type of this tissue, stratified columnar epithelium, is only found in a few places in the body, including parts of the anus, conjunctiva in the eye, uterus, and pharynx. Epithelial tissue is classified in two ways: based on structure, and based on form and function.