How do vocal cords ?

Question

function.

Answer 1

The vocal folds, also known commonly as vocal cords, are composed of twin infoldings of mucous membrane stretched horizontally across the larynx. They vibrate, modulating the flow of air being expelled from the lungs during phonation.Open during inhalation, closed when holding one's breath, and vibrating for speech or singing (oscillating 440 times per second when singing A above middle C); the folds are controlled via the vagus nerve.

The larynx is a major (but not the only) source of sound in speech, generating sound through the rhythmic opening and closing of the vocal folds. To oscillate, the vocal folds are brought near enough together such that air pressure builds up beneath the larynx. The folds are pushed apart by this increased subglottal pressure, with the inferior part of each fold leading the superior part. Under the correct conditions, this oscillation pattern will sustain itself. In essence, sound is generated in the larynx by chopping up a steady flow of air into little puffs

The perceived pitch of a person's voice is determined by a number of different factors, not least of which is the fundamental frequency of the sound generated by the larynx. A person's natural fundamental frequency is influenced by many factors, including the length, size, and tension of the vocal folds. In an adult male, this frequency averages about 125 Hz, adult females around 210 Hz, in children the frequency is over 300 Hz. Depth-Kymography is an imaging method to visualize the complex horizontal and vertical movements of vocal folds.

The vocal folds discussed above are sometimes called 'true vocal folds' to distinguish them from the false vocal folds. These are a pair of thick folds of mucous membrane that sit just above, and protect the more delicate true folds. They have minimal role in normal phonation, but are often used in musical screaming and the death grunt singing style. They are also used in Tuvan throat singing. The false folds are also called vestibular folds and ventricular folds. They can be seen on the diagram above as ventricular folds. False vocal folds, when surgically removed, can regenerate completely.

Answer 2

Try reading the article in http://en.wikipedia.org/wiki/Vocal_folds  

Answer 3

The human voice consists of sound made by a human being using the vocal folds for talking, singing, laughing, crying, screaming, etc. Human voice is specifically that part of human sound production in which the vocal folds (vocal cords) are the primary noise source. Generally speaking, the voice can be subdivided into three parts; the lungs, the vocal folds, and the articulators. The lung (the pump) must produce adequate airflow to vibrate vocal folds (air is the fuel of the voice). The vocal folds (vocal cords) are the vibrators, neuromuscular units that ‘fine tune’ pitch and tone. The articulators (vocal tract consisting of tongue, palate, cheek, lips, etc.) articulate and filter the sound.

The vocal folds, in combination with the articulators, are capable of producing highly intricate arrays of sound. The tone of voice may be modulated to suggest emotions such as anger, surprise, or happiness. Singers use the human voice as an instrument for creating music.

Answer 4

Like two rubber bands pressed against each other with wind blowing through them.  They vibrate and make sound.

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