Structure and function of the trachea

The trachea is a very important part of the airways that connects the larynx to the bronchi. It is through her that the air passes through the lungs along with the necessary amount of oxygen. The trachea is a tubular hollow organ. The length of this tube varies from 8.5 to 15 centimeters, depending on the physiological characteristics of the body. But before considering the main functions of the trachea, you need to familiarize yourself with its anatomy.

The location of the trachea . The trachea begins from the cricoid cartilage approximately at the level of the sixth cervical vertebra. The third part of this tube is at the level of the cervical spine, and the rest - in the thoracic region, where the trachea ends at the level of the fifth thoracic vertebra. In this area, the trachea divides into two bronchi, forming a fork, - this is the point of bifurcation, which is intertwined with the arch of the aorta.

If we consider the cervical part of this organ, then in front of it lies part of the thyroid gland. Throughout the back to the tracheal tube adjoins the esophagus. On each side is a neurovascular bundle, which includes fibers of the vagus nerve, internal jugular veins and carotid arteries.

Trachea: structure . If we consider the transverse section of the trachea, it can be seen that it consists of several layers - the mucosa proper, the submucosa, the cartilaginous part and the adventitial membrane. Functions of the trachea, like any other organ, are partially dependent on the structure, so you need to consider each part in more detail.

Mucous membrane - is represented by ciliate multilayer epithelium, which lies on the basement membrane. Cilia of the cells move toward the larynx. The structure of the epithelium also includes stem cells, as well as goblets, which release a small amount of mucus. There are cells of internal secretion that produce serotonin and norepinephrine. The basal membrane has many elastic fibers. There are also smooth, separate myocytes, located in a circle.

The submucosa layer is a fibrous, loose connective tissue. It is in this layer is the bulk of nerve fibers and small vessels that are responsible for regulation and blood supply.

The cartilage layer is formed by hyaline incomplete cartilages, which occupy two-thirds of the circumference of the tracheal tube. Between themselves, the cartilages are connected by annular ligaments. The number of cartilage in a person varies from 16 to 20. Behind the back wall is formed, which is in contact with the esophagus. Thus, the passage of the food lump does not interfere with the respiratory process.

The adventitial part of the trachea is a thin connective tissue covering the tube from the outside.

As you can see, the anatomy of the trachea is not that complicated.

Functions of the trachea . The main function of the tracheal tube is to hold air to the lungs. But these are not all functions of the trachea.

As already mentioned, the mucous membrane of the trachea is covered with a ciliary (ciliary) epithelium, the motions of which are directed toward the larynx and oral cavity. In addition, goblet cells secrete mucus. When the foreign air enters the trachea of small foreign bodies, for example, dust, the particles are covered with mucus and the cilia move back into the larynx and pass into the pharynx. Thus, the trachea performs a protective function. In the case of a large foreign body, a reflex cough begins, during which the trachea significantly narrows in the lumen.

As you know, cleansing and warming of air occurs in the nasal cavity, but partially this function is performed by the trachea. In addition, the trachea is a resonator during speech, as it pushes the air to the vocal cords.

If to summarize, you can see that, despite the rather simple structure, the trachea has a number of very important functions, without which the existence of the human body is impossible.