La larynx It is a hollow and mobile organ of the respiratory system associated with multiple key functions in the human body. It is a conduit formed by the superposition of cartilages covered by respiratory mucosa. The cartilages that make it up include the epiglottic cartilage spoon-shaped, the thyroid cartilage in the form of an open book facing backwards, the cricoid cartilage ring-shaped, the arytenoid cartilages that have a pyramidal shape, and the corniculate cartilages hook-shaped. These structures are articulated and connected by small synovial joints, which move through the intrinsic muscles of the larynx.
Anatomy of the larynx
The larynx is located in the neck and extends from the top of the trachea to the base of the tongue, just below the hyoid bone. It is composed primarily of cartilages that provide rigidity and support, while muscles allow its mobility during speech, breathing, and swallowing. The main cartilages of the larynx are:
- Epiglottic cartilage: Located at the top of the larynx, this cartilage is shaped like a leaf and plays an essential role in swallowing by closing the entrance to the larynx to prevent food from entering the airway.
- Thyroid cartilageIt is the largest of the laryngeal cartilages and forms the laryngeal prominence, commonly known as the “Adam’s apple”.
- cricoid cartilage: It is shaped like a ring and is located just below the thyroid cartilage. Unlike the other cartilages, it is the only one that forms a complete ring around the trachea.
- Arytenoid cartilagesThese pyramid-shaped cartilages help control the opening and closing of the vocal cords during phonation.
In addition to these cartilages, the larynx is composed of intrinsic and extrinsic muscles that facilitate movements essential for breathing, swallowing, and speaking. The intrinsic muscles alter the position and tension of the vocal cords, while the extrinsic muscles move the larynx as a whole.
Functions of the larynx
The larynx has several vital functions:
- Protection of the lower respiratory tract: During swallowing, the larynx moves up and forward, and the epiglottis tilts downward to seal the entrance to the larynx, preventing food from entering the airway. If an object accidentally enters, the cough reflex is activated to expel it.
- Facilitating breathing: During breathing, the muscles of the larynx separate the vocal cords to allow air to pass into the lungs and expel carbon dioxide during exhalation.
- sound production: The larynx is the main organ of phonation. When air passes through the vocal cords, they vibrate, creating sound. The tension, length, and thickness of the vocal cords determine the pitch and timbre of the voice. The frequency of the vibrations produces higher or lower tones.
Vascularization and innervation of the larynx
The larynx is irrigated by the superior and inferior laryngeal arteries. These arteries are direct branches of the superior and inferior thyroid arteries, respectively, which in turn arise from the external carotid and subclavian arteries. The larynx is drained by the lymphatic vessels which are divided into two large groups: those that drain the supraglottis towards the upper cervical nodes and those that drain the subglottis towards the deep cervical nodes.
La innervation The larynx is supplied by the superior and inferior laryngeal nerves, both branches of the vagus nerve (cranial nerve X). These nerves provide motor and sensory support, ensuring that the vocal cords and the larynx as a whole function properly during breathing and phonation.
Vocal chords
The central part of the larynx contains the vocal folds, commonly known as vocal cords, which are key structures for sound production. They are divided into two groups:
- False vocal cords, which do not participate in phonation, but help close the larynx during swallowing.
- True vocal cords, which are primarily responsible for creating sound. They are made up of mucous tissue and a vibrating muscle that generates sound when air passes through them.
Between the true and false vocal cords is a space called the glottis, which opens and closes during breathing and sound production.
Diseases and pathologies of the larynx
Laryngitis
One of the most common conditions of the larynx is laryngitis, which is characterized by inflammation of the laryngeal mucosa. It can be acute, caused by viral infections, or chronicle, associated with irritating factors such as tobacco or gastroesophageal reflux.
Symptoms of laryngitis
- Dysphonia (difficulty speaking).
- Sore throat.
- Dry cough.
- Mild fever, in cases of viral infection.
Vocal cord disorders
In addition to laryngitis, there are other problems related to the vocal cords, such as nodules o vocal polyps, which mainly affect people who overuse or misuse their voice, such as singers or teachers.
laryngeal cancer
El laryngeal cancer This is another serious disorder that often affects people who smoke or consume alcohol excessively. This type of cancer usually manifests itself as tumors on the vocal cords or other parts of the larynx.
Differences by sex and age
The male larynx is larger than that of the female, resulting in a deeper voice due to longer and thicker vocal cords. During puberty, the male larynx grows rapidly, which explains the voice changes in adolescent boys.
In the childrenIn infants, the larynx is positioned higher than in adults, allowing for simultaneous breastfeeding and breathing. This position descends as the child grows, enabling the separation of these functions. Proper laryngeal function is crucial for the overall health of the respiratory system and for verbal communication. Laryngeal pathologies can significantly impair quality of life, affecting everything from breathing to the ability to speak.