THROAT - Anatomy, respiration, voice & swallowing
A brief introduction to the throat's anatomy
The throat (or pharynx) makes up a large area of the head and neck and for convenience is divided into three areas: the nasopharynx, the oropharynx, and the hypopharynx.
The throat actually starts at the back of the nose, hence the name (naso- for nose and -pharynx for throat). The main purpose of this area of the throat is to transfer inhaled air down through the voice box (the larynx) and into the lungs. The openings of the Eustachian tubes are located in the nasopharynx, as are the adenoids. Read more about the Eustachian tubes here and more about the adenoids here.
Problems that can occur in the nasopharynx include:
- Eustachian tube dysfunction (causing the sensation of blocked or popping ears)
This is the next part of the throat and is located behind the mouth (the oral cavity), hence the name (oro- for oral cavity). The oropharynx is responsible for transferring food and drink to the food pipe (the oesophagus) and on to the stomach. The tonsils are located in the oropharynx. Read more about the tonsils here.
Problems that can occur in the oropharynx include:
- Tonsil stones (also called tonsilloliths)
This part of the throat is located behind the larynx and is where everything coming in from the nasopharynx and oropharynx are redirected to their appropriate destinations. The epiglottis is located here. This is a flap-like structure that acts as a lid for the larynx and closes shut during swallowing to keep food and drink out of the windpipe (the trachea).
Problems that can occur in the hypopharynx include:
- Globus pharyngeus (the sensation of a lump in the throat)
Respiration and voice
The voice box, or larynx, is important for (1) protecting the lungs from food, drink and inhaled foreign bodies (2) acting as a passage way for air from the nasopharynx (and to a lesser extent the oropharynx) into the trachea and down to the lungs, and (3) voice. As mentioned above, the epiglottis does much of the work of protecting the trachea and lungs from anything but air entering them.
The power for your voice comes from air that you exhale. When you inhale, the diaphragm lowers and the rib cage expands, drawing air into the lungs. As you exhale, the process reverses and air exits the lungs, creating an airstream in the trachea. This airstream provides the energy for the vocal cords in the larynx to produce sound. The stronger the airstream, the stronger the voice.
The larynx sits on top of the trachea. It contains two vocal cords that open during breathing and close during swallowing and voice production. When you produce voice, the airstream passes between the two vocal cords that have come together. These cords are soft and are set into vibration by the passing airstream. They vibrate very fast from 100 to 1000 times per second, depending on the pitch of the sound you make. Pitch is determined by the length and tension of the vocal cords, which are controlled by muscles in the larynx.
By themselves, the vocal cords produce a noise that sounds like simple buzzing. All of the structure above the cords, including the three areas of the throat, the nose, and the mouth, act as a resonator system. The buzzing sound created by vocal cord vibration is changed by the shape of all these other structures to produce our unique human sound. As everyone's anatomy is slightly different, we all produce different voices.
Problems that can occur with the larynx include:
- Muscle tension dysphonia
More information on swallowing will soon be available.