Nepedia
Back to Discover
Advanced Reader
🧬

Larynx

life science Maturity 11-13 Next article →

The larynx is a vital organ located at the top of the neck.

Larynx
Larynx

It is commonly known as the voice box. This organ serves three primary functions. It assists in respiration by managing airflow. It produces sound through the manipulation of pitch and volume. Most importantly, it protects the trachea, or windpipe, against food aspiration. The larynx sits just below the point where the pharynx splits into the trachea and the esophagus. Its opening, called the laryngeal inlet, is approximately 4 to 5 centimeters in diameter.

The structure of the larynx is complex and triangle-shaped. It is composed of nine cartilages that form a protective skeleton. Three of these cartilages are unpaired: the epiglottis, the thyroid cartilage, and the cricoid cartilage. The thyroid cartilage creates the laryngeal prominence, often called the Adam's apple. The cricoid cartilage is a ring of hyaline cartilage that forms the bottom wall of the larynx. The epiglottis is a large, spoon-shaped piece of elastic cartilage.

Normal Epiglottis
Normal Epiglottis

The other six cartilages are paired: the arytenoid, corniculate, and cuneiform cartilages. These paired structures provide essential support and movement for the internal folds.

Inside the larynx, the cavity is divided into several distinct areas. The upper part is the vestibule, located above the vestibular folds. These upper folds are often called the false vocal cords because they do not participate in vocalization. Some throat singing styles, like Kargyraa or Umngqokolo, actually use these folds to create low sounds. Below the vestibular folds lies the laryngeal ventricle. The most critical part is the glottis, which consists of the vocal cords and the rima glottidis. The rima glottidis is the narrow, slit-like space between the left and right vocal cords.

Illu07 larynx02
Illu07 larynx02

Below the glottis is the infraglottic cavity, which connects directly to the trachea.

Muscle movement is what allows the larynx to function. There are two types of muscles: extrinsic and intrinsic. Extrinsic muscles support and position the larynx within the neck. Intrinsic muscles are contained entirely within the larynx. These intrinsic muscles are further divided into respiratory and phonatory groups. Respiratory muscles, such as the posterior cricoarytenoid, move the vocal cords apart to allow breathing. Phonatory muscles move the cords together to produce sound.

Gray386
Gray386

The cricothyroid muscle is unique because it lengthens and tenses the vocal cords to change pitch.

Sound production is a precise mechanical process. To create sound, the vocal cords must be held close together through a process called adduction. This is achieved by the arytenoid cartilages. When air from the lungs passes through the constricted glottis, the cords vibrate. The larynx can manipulate the fundamental frequency, or pitch, of this sound. This happens by changing the tension or length of the vocal cords. The volume is also affected by the strength of expiration from the lungs. Once the sound is created, it is filtered by the tongue, lips, and mouth to form words.

Biological development and nerve supply are also highly specialized. The larynx develops from the mesoderm of the fourth and sixth pharyngeal arches. In newborn infants, the larynx sits higher in the neck, near the C2 and C3 vertebrae. As a person grows, the larynx descends to its adult position near the C3 to C6 vertebrae. The organ is controlled by branches of the vagus nerve. The recurrent laryngeal nerve provides motor innervation to most intrinsic muscles. If this nerve is injured on both sides, it can cause significant difficulty breathing.

Kehlkopf Pferd
Kehlkopf Pferd

Understanding the larynx reveals how the body manages complex tasks simultaneously. It must remain open for breathing while being able to close instantly during swallowing. The epiglottis acts as a lid, moving down to cover the glottis when food is swallowed. This prevents food from entering the respiratory tract. The laryngeal muscles also show a unique ability to handle calcium changes. This allows them to perform very fast, repetitive work for long periods. This specialized biology ensures that we can communicate and breathe safely at the same time.

658 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (5)
File:Larynx.svg
Larynx.svg
File:Illu07 larynx02.jpg
Illu07 larynx02.jpg
File:Gray386.png
Gray386.png
File:Normal Epiglottis.jpg
Normal Epiglottis.jpg
File:Kehlkopf Pferd.jpg
Kehlkopf Pferd.jpg
More to explore

✨ What else?

Related topics you might enjoy

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.