Trachea is a very important part of the airways that connects the larynx to the bronchi. It is through it that air passes into the lungs along with the necessary amount of oxygen. Trachea is a tubular hollow organ. The length of this tube ranges from 8.5 to 15 centimeters, depending on the physiological characteristics of the body. But before considering the basic functions of the trachea, it is necessary to familiarize yourself with its anatomy.
The location of the trachea . Trachea starts from the cricoid cartilage at about the level of the sixth cervical vertebra. The third part of this tube is at the level of the cervical spine, and the rest is in the thoracic region, where the trachea ends at the level of the fifth thoracic vertebra. In this area, the trachea is divided into two bronchi, forming a fork - this is the bifurcation point, which is intertwined with the aortic arch.
If we consider the cervical part of this organ, then in front of it lies a part of the thyroid gland. Throughout the back, the esophagus is adjacent to the tracheal tube . On the sides there is a neurovascular bundle, which includes the fibers of the vagus nerve, internal jugular veins and carotid arteries.
Trachea: structure . If we consider the transverse section of the trachea, we can see that it consists of several layers - the mucous membrane itself, the submucosal layer, the cartilaginous part and the adventitia. The functions of the trachea, like any other organ, partially depend on the structure, so you need to consider each part in more detail.
Mucous membrane - is represented by ciliary multilayer epithelium, which lies on the basement membrane. Cilia of cells move towards the larynx. The epithelium also includes stem cells, as well as goblet cells, which secrete a small amount of mucus. There are also internal secretion cells that produce serotonin and norepinephrine. The basement membrane has many elastic fibers. There are smooth, separate myocytes arranged in a circle.
The submucosal layer is a fibrous, loose connective tissue. It is in this layer that the bulk of nerve fibers and small vessels are located, which are responsible for regulation and blood supply.
The cartilage layer is formed by incomplete hyaline cartilage, which occupy two-thirds of the circumference of the tracheal tube. Cartilages are connected by annular ligaments. The number of cartilage in a person ranges from 16 to 20. A membranous wall is formed in the back, which is in contact with the esophagus. Thus, the passage of the food lump does not interfere with the respiratory process.
The adventitious part of the trachea is a thin connective tissue membrane that covers the tube from the outside.
As you can see, the anatomy of the trachea is not so complicated.
The functions of the trachea . The main function of the tracheal tube is to conduct air to the lungs. But these are not all the functions of the trachea.
As already mentioned, the mucous membrane of the trachea is covered with ciliated (ciliary) epithelium, the movements of which are directed towards the larynx and oral cavity. In addition, goblet cells secrete mucus. When small foreign bodies, such as dust, get into the trachea with air, the particles are enveloped in mucus and, with the movement of the cilia, are pushed back into the larynx and pass into the pharynx. Thus, the trachea also performs a protective function. If a large foreign body enters, a reflex cough begins, during which the trachea significantly narrows in the lumen.
As you know, air purification and warming takes place in the nasal cavity, but the trachea also partially performs this function. In addition, the trachea is a resonator during speech, as it pushes air to the vocal cords.
To summarize, we can see that, despite the fairly simple structure, the trachea has a number of very important functions, without which the existence of the human body is impossible.