[Physics Class Notes] on Vocal Cord – The Source of Human Voice Pdf for Exam

Introduction

Communication is one of the great discoveries of human beings. It not only helps us to understand but also to express ourselves. This process of understanding and expressing is not only done by humans but also by animals, microorganisms too, but we definitely do it on a better level.

It establishes interconnectivity between individuals everyday. It even simply does not give us a pace to speak but express our different expressions e.g. crying , yelling, laughing , screaming , shouting , singing, and many more.

Vocal Cord the Source of Human Voice

We communicate by means of our voice which has different expressions and tone as well. For e.g. a new born baby’s tone can easily be understood though it cannot speak. A young boy’s tone can easily be recognised, an old man’s tone can easily be recognised, an  angry womens tone can be recognised, we can differentiate between the voice of a girl and a  boy.

All these tones and voices which we can easily differentiate are due to the vocal cord.

Scientists study shows that the twelve voice notes on which the maximum portion of music is based has got its base from human voice during the time of evolution.

The size of the larynx differs in different individuals.

This size differentiation basically denotes the difference in pitch of both the genders, where the females pitch is considered high as compared to the male .

E.g. a male voice has the bass, baritone, tenor and countertenor,  while the females voice possess contralto, mezzo soprano etc .

There are many folds in the larynx.

These get attached to the back side of the arytenoids, cartilages and at the front of the thyroid cartilages .There are no outer edges in the breathing tube while the inner one has full freedom to vibrate .

There are three layers within, them which are :

The epithelium layer, the vocal ligament and the muscles which is also known as the vocalis muscle .

Another feature they possess are the triangular bands that are pearly white in color.

Both sides of vocal cords have vestibular folds, other names for false vocal cords.

It  has small space between the folds as shown below:

[]

The sound which we produce is entirely different from others not only because of the shape and size of the vocal cord but because of the shape and size of the human body and its shape and size of the human body, especially the vocal tracks that become habitual the way we speak.

For producing different pace or tones of sound we could try doing things eg tightening or loosing our tongue or inflammation in lungs .

Any methods like this could result in the change of voice.

Now, that we know the importance of the vocal cord,  we must be aware of the diseases that occur in the vocal cord .

There are many disorders which can affect the human voice,  these are speech impediments ,   growths of vocal folds or lessening up of vocal folds at times vocal loading also gets inflicted on the speech organs.

Though There are remedies to these problems by vocal therapies or voice therapies .

The Main Parts of Voice Production

However,  we wonder that this beauty of expressing ourselves and understanding others is fitted inside us in a compact manner.

These are broadly divided into three types:

1. The first one is lungs which is also known as the power source.

2. The second subdivision is the voice box which is also known as vibrator or larynx.

3. The last ones are throat, nose, mouth and sinuses which are also known as the resonators or articulators.

Heading toward the 1st process of sound formation : the lungs ;

Now looking into the  process of working,  we will see that the lungs which are also the pump,  must produce an adequate amount of air flow and air pressure to vibrate the vocal folds or vocal cords.

The 2nd part is  larynx (voice box)

Larynx : it’s a structure on the top of the windpipe .

It is responsible for sound production.

Vocal folds : soft tissue which is the main vibratory component of the voice box.

Glottis :(also called rima glottidis): it opens between two vocal cords .

It opens during breathing and closes during swallowing.

Voice = sound +resonance +articulation.

A huge amount of air pressure is  sent towards the vocal folds

Diaphragm, abdominal muscle, chest muscle, rib cage, coordinates to move the air out of the lungs and towards the vocal chord.

Thereafter, the vocal folds vibrate which creates a sequence of vibratory cycles.

To the midline of the voice box vocal folds are moved by the help of muscles, nerves, cartilages.

This cycle repeatedly occur on vibratory cycle as as following:

Air pressure- : it opens vocal folds, air pressure continues to move in upward directions to the top of vocal folds and opens it’s top.

Closure of vocal folds-: it cuts off air pressure and releases a pulse of air.

The new cycle starts again after that..

These cycles produce voice stands which is a buzzy sound, it is then amplified by vocal tract resonators producing sound.

Diagram Depicting Sound Frequencies:

[]

(when Loudness is increasing- its known as amplitude and when frequency is increasing- then it’s known as pitch).

The third and the last part includes nose , pharynx, mouth, amplifying and modifying sound.

The muscles of the larynx have a tongue (lips, cheek etc) which filters the sound and articulates it from the larynx.

It allows to take different quality of voice’

E.g. a trombone player playing its instrument by mouth and as the slide is changed the sound automatically changes.