Structure and function of the larynx

The human larynx is located at the level of 4-6 cervical vertebrae. Outside, its position is noticeable on the ledge, called "Adam's apple" or "Adam's apple," more developed in men. On each side of the larynx is the right and left vascular-neural bundle of the neck and thyroid lobe, behind - the laryngeal part of the pharynx, in front of the larynx is covered by the superficial muscles of the neck. At the top of the larynx it communicates with the pharynx cavity, at the bottom - with the trachea.

The base of the larynx, its skeleton, consists of cartilages, which are connected by ligaments and joints. There are three unpaired cartilage - thyroid, cricoid, epiglottis and three paired - arytenoid, carobiform and sphenoid. In the larynx there are two joints, both paired: perstneshchitovidny and perstnecherpalovidny. They are strengthened with small ligaments, other laryngeal ligaments are more powerful. Ring-like cartilage is the base of the larynx, its support. The arytenoid cartilages located on its plate have two processes - the vocal and muscular. Due to the vertical rotations and sliding movements of the arytenoid cartilages in the pericoptera, the vocal cracks narrows and widens. The transcranial joint provides tension and relaxation of the vocal folds. Above, the larynx is closed by the epiglottis, it is located in front of the entrance to the larynx and is attached to the thyroid cartilage and the hyoid bone.

The muscles of the larynx are divided into the outer and inner, the external muscles lift and lower the larynx. The internal muscles of the larynx set in motion the cartilages of the larynx, change the width of the glottis. Internal muscles are divided into several groups: the narrowing of the glottis; Expander of the glottis; Muscle assistants; Muscles that control the vocal folds; Muscle, providing mobility of the epiglottis. The voice gap narrows or widens under the influence of contraction of a group of muscles receiving a pulse from the central nervous system.

The cavity of the larynx resembles in shape an hourglass: in the middle section it is narrowed, upward and downward. From the inside, the larynx cavity is lined with a mucous membrane. The border of the upper part - the threshold of the larynx - is the folds of the vestibule (false vocal folds), they are located above the vocal folds and are formed by the mucous membrane, connective tissue and muscle fibers.

The narrowest section is the middle one, it is formed by vocal folds, between them there is a voice gap. The vocal folds are stretched between the anterior soldering of the thyroid cartilage and the vocal appendages of the arytenoid cartilages. Their basis is the vocal muscle, the vocal cords and connective tissue. The length of the vocal folds in men is 18-25 mm, in women 14-21 mm. Between the vocal folds and folds of the vestibule are the ventricles of the larynx, which blindly terminate.

Under the vocal folds is the underlay space - the lower larynx. The mucous membrane here is thickened, loose, contains many glands. Podskladkovoe space goes into the cavity of the trachea.

Functions of the larynx

Various, first of all, the formation of sounds occurs in the larynx. The voice is formed during exhalation, when the vocal folds are closed, however, the diaphragm, lungs, bronchi and trachea, larynx, pharynx, as well as the oral cavity, nose and paranasal sinuses take part in the phonation. The nascent sound in the larynx does not yet resemble a sonorous voice, as we hear it. Its natural timbre, as well as its strength and height, is acquired by the resonators - air cavities, different in shape and volume, located above and below the vocal cracks. In the larynx, the main sound is formed, speech is formed in the "extra" tube and becomes possible due to the movement of the lips, soft palate, tongue, lower jaw.

The larynx is involved in breathing. The amount of air entering the lower respiratory tract is regulated by the expansion and narrowing of the glottis. With quiet breathing, the vocal cleft slightly widens when inhaled and tapers when exhaled. With a deep inspiration, it greatly expands, and with a delay in breathing - it narrows extremely.

When swallowed, the epiglottis closes the entrance to the larynx, separating the respiratory and digestive tract, thereby protecting the respiratory tract from food ingestion. Another protective device is a reflex cough that develops when foreign substances enter the larynx or liquid and gaseous particles contained in the air. Coughing is a kind of exhaled exhalation that helps to remove foreign bodies and harmful impurities from the respiratory tract.