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.
A simple squamous epithelium is a single layer of flat cells in contact with the basal lamina (one of the two layers of the basement membrane) of the epithelium.This type of epithelium is often permeable and occurs where small molecules pass quickly through membranes via filtration or diffusion.Simple squamous epithelia are found in capillaries, alveoli, glomeruli, and other tissues where rapid diffusion is required. Cells are flat with flattened/rounded nucleus.It is also called pavement epithelium due to its tile-like appearance.his type of epithelium is often permeable and occurs where small molecules pass quickly through membranes via filtration or diffusion. Simple squamous epithelia are found in capillaries, alveoli, glomeruli, and other tissues where rapid diffusion is required. Cells are flat with flattened/rounded nucleus.