key term - Vocal Cords

Definition

Vocal cords are two bands of muscle and ligament tissue located in the larynx that vibrate to produce sound for speech. They play a crucial role in the application of Bernoulli's Equation, which describes the relationship between pressure, velocity, and elevation in fluid dynamics.

5 Must Know Facts For Your Next Test

1. The vocal cords can be brought together (adducted) or pulled apart (abducted) to control the flow of air through the glottis, which is essential for speech and other vocalizations.
2. The Bernoulli effect, as described by Bernoulli's Equation, causes a decrease in pressure as air flows through the narrowed glottis between the vocal cords, leading to their vibration and sound production.
3. The tension and thickness of the vocal cords can be adjusted by the intrinsic and extrinsic muscles of the larynx, allowing for the modulation of pitch and volume of the voice.
4. Air pressure below the vocal cords (subglottic pressure) is a key factor in determining the amplitude and frequency of vocal cord vibrations, and thus the loudness and pitch of the voice.
5. Abnormalities or dysfunction of the vocal cords, such as paralysis or nodules, can lead to voice disorders and difficulty with speech and vocalization.

Review Questions

• Explain how the Bernoulli effect, as described by Bernoulli's Equation, contributes to the vibration of the vocal cords and the production of sound.
  • As air flows through the narrowed opening between the vocal cords (the glottis), the Bernoulli effect causes a decrease in pressure within the glottis. This decreased pressure, as described by Bernoulli's Equation, leads to the vocal cords being drawn together, or adducted. The subsequent increase in airflow velocity through the glottis then causes the vocal cords to vibrate, generating sound waves that are amplified and modulated to produce speech and other vocalizations.
• Describe the role of subglottic pressure in the vibration of the vocal cords and the regulation of voice pitch and volume.
  • Subglottic pressure, the air pressure below the vocal cords, is a critical factor in determining the amplitude and frequency of vocal cord vibrations. Higher subglottic pressure increases the force driving the vocal cords apart, leading to greater vibration amplitude and louder voice volume. Conversely, lower subglottic pressure results in smaller vibration amplitude and quieter voice volume. The intrinsic and extrinsic muscles of the larynx can adjust the tension and thickness of the vocal cords, which, in combination with subglottic pressure, allows for the modulation of voice pitch.
• Analyze how abnormalities or dysfunction of the vocal cords can impact an individual's ability to produce speech and other vocalizations.
  • Disorders affecting the vocal cords, such as paralysis or the formation of nodules, can significantly impair an individual's ability to produce clear and effective speech. Vocal cord paralysis can prevent proper adduction and vibration of the cords, leading to a breathy, weak voice. Vocal cord nodules, which are benign growths on the cords, can alter their mass and tension, resulting in hoarseness, vocal fatigue, and difficulty projecting the voice. These types of vocal cord abnormalities can severely compromise an individual's communication abilities and quality of life, underscoring the critical role of the vocal cords in speech production.

Related terms

Larynx: The voice box, or larynx, is the upper portion of the respiratory tract that contains the vocal cords and is responsible for sound production.

Glottis: The opening between the vocal cords, which can be opened or closed to regulate airflow and produce different sounds.

Subglottic Pressure: The pressure of air below the vocal cords, which is an important factor in the vibration of the cords and sound production.