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.
There is different types of squamous epithelium: simple and stratified. The function of simple squamous epithelium: It is good for the passage of materials via diffusion. For example, it forms the tiny air sacs of the lungs and the walls of capillaries.It also forms the smooth, friction-reducing interior lining of the heart, blood vessels, thoracic cavity, and abdominal cavity.he alveoli is just one cell layer thick so that diffusion of gasses between the capillaries and the alveoli is easy. Simple squamous epithelium are found in the capillary wal â¦ ls and the alveolar walls. They are thin so diffusion is easy.