As the respiratory tube branches become smaller in diameter,
A)they have increased cartilage.
B)they have increased muscle fibers.
C)the epithelial lining changes to connective tissue.
D)the epithelial lining changes from pseudostratified ciliated columnar to cuboidal and simple squamous epithelium.

Question

As the respiratory tube branches become smaller in diameter,
A)they have increased cartilage.
B)they have increased muscle fibers.
C)the epithelial lining changes to connective tissue.
D)the epithelial lining changes from pseudostratified ciliated columnar to cuboidal and simple squamous epithelium.

Quizplus · Accepted Answer

As the respiratory tube branches become smaller in diameter, the epithelial lining changes from pseudostratified ciliated columnar to cuboidal and simple squamous epithelium. This is because the function of the smaller branches changes from primarily conducting air to facilitating gas exchange between the air and the bloodstream. The changes in epithelial lining allow for more efficient diffusion of gases across the respiratory membrane. The amount of cartilage decreases as the bronchioles become smaller, and there is no significant increase in muscle fibers.

As the Respiratory Tube Branches Become Smaller in Diameter