Glands, such as the thyroid, that secrete their products directly into the blood rather than through ducts are classified as ________ glands.

A. aids in digestion:Ciliated pseudostratified columnar epithelium is not involved in digestion. Digestive functions are primarily handled by simple columnar epithelium in the gastrointestinal tract.

B. is more durable than all other epithelia:While pseudostratified epithelium provides some protection, it is not the most durable epithelium. Stratified squamous epithelium is better suited to withstand abrasion and mechanical stress.

C. is found in some of the larger glands:Some simple columnar or cuboidal epithelia line glands, but ciliated pseudostratified columnar epithelium is not characteristic of glandular linings.

D. lines most of the upper respiratory tract:The ciliated pseudostratified columnar epithelium with goblet cells lines the nasal cavity, trachea, and bronchi. The cilia move mucus and trapped particles toward the throat, helping to clean and protect the respiratory system.

A. fibrocartilage CT:Fibrocartilage provides strong support and shock absorption in areas such as intervertebral discs and the pubic symphysis, but it is too rigid to maintain the flexible shape of the external ear.

B. elastic cartilage CT:Elastic cartilage contains a dense network of elastic fibers that provide both strength and flexibility. This allows the external ear (pinna) to maintain its shape while remaining pliable.

C. adipose tissue CT:Adipose tissue stores fat and cushions structures but does not provide the structural framework necessary to maintain the shape of the ear.

D. hyaline cartilage CT:Hyaline cartilage is found in structures such as the trachea and nose, providing support with limited flexibility. It is not elastic enough to preserve the shape of the external ear.