Ciliated pseudostratified columnar epithelium is the type of tissue that lines parts of the respiratory system, such as the nasal cavities and trachea. Epithelial tissues generally cover and protect various parts of the body. They can be different shapes, can be layered, and can even secrete mucus. Some of these tissues have cilia embedded in them. Their names describe their characteristics and give clues about where they can be found in the body.
The word "ciliated" is derived from Latin and refers to a small hair that projects from the surface. Ciliated pseudostratified columnar epithelium has small hair-like projections embedded in the membrane. They are used to sweep away debris that could harm the underlying tissues or structures. Like a small broom, the cilia keep the area free from particles.
Pseudo in Latin means "false" and stratified means "layers." These tissues look like there are multiple layers, but there really is only one. This stems from the alignment of the individual cells. When the nuclei do not line up, it can cause a pseudostratified appearance.
The shape of the individual epithelial cells is described by the term "columnar." These cells are longer than most epithelial cells and resemble a column shape. The elongated shape is what causes the nuclei not to line up and add to the pseudostratified appearance. Columnar epithelium can be compressed a great deal, allowing the tissues to change shape. This is important for the respiratory tract, especially the bronchi, so it can expand and contract as a human breathes in and out.
Some types of epithelial tissues are also gobleted. Gobleted cells secrete mucus, which also helps protect various areas in the human body. Mucus is a thick, sticky substance that can trap harmful particles such as dust and bacteria. This is especially important in the lining of the nose and nasal cavities. The mucus and the ciliated pseudostratified columnar cells protect the body by filtering out or trapping substances in the upper respiratory tract that could cause damage if they enter the lungs.
Pseudostratified tissue can also be found in other parts of the human body. The epididymis, where sperm mature in males, also makes use of this type of tissue. Other parts of the male reproductive system, such as the vas deferens, are lined with a type of pseudostratified columnar epithelium that is non-ciliated.