VOCAL TRACT

1. The respiratory system
   
   The lungs are spongy bodies composed of many small air sacks called the alveoli.
   The alveoli relive air from bronchioles which come together into 2 tubes – the bronchi
   The bronchi turn into trachea through which the air passes from the throat to the lungs. The lungs are enclosed in a large sack – the pleura – and they’re encased in the thoracic cavity.
   The lungs are bounded above and laterally by the rib cage (chest) and below by the diaphragm.

2. The mechanism of respiration
   
   There are two types of physical movements associated with the gaseous exchange.
   
   Inspiration or Inhalation
   During inspiration, the outer intercostal muscles contract, which raises the chest cavity or the ribs. This is accompanied by the lowering of the diaphragm. Together these movements serve to increase the area of the thoracic cavity, which reduces the pressure. The air from outside rushes into the lungs.

Inspiration

After the internal respiration in the lungs, the impure air is expelled in the following manner:

Expiration or Exhalatio
The inner intercostal muscles contract bringing the ribs back to the original position and the diaphragm is also raised back by the action of the abdominal muscles. This reduces the space in the chest cavity and increases the pressure. This expels the air out of the lung.

1. Trachea
   Composed of a numer of incomplete cartilagous rings open on the dorsal side. The uppermost ring of trachea forms the base of the larynx. This ring is a complete circle and it’s called:
   CIRCOIO CARTILAGE
   The most important cartilage in the larynx is a thyroid cartilage which forms the Adam’s apple on the front side of the larynx
   The epiglottis is a spoon-shaped cartilage whose lower tip is fastened to the thyroid cartilage . The epiglottis can be moved by the movement of the tounge and the tounge bone (hyoid bone)
   

2. Larynx and the vocal folds
   
   Vocal cords = ligaments and muscle
   Brought together by the arytenoid cartilages which are the point of origin of vocal cords
   The opening between the VC = glottis
   Size of VC depends on sex, age
   

3. The Supraglottal Tract
   
   The pharynx is the tube – shaped channel which leads from the larynx to the mouth and to nasal cavity.
   The passage above the larynx is known as the vocal tract
   there are 2 types of the articulators:
   - ACTIVE
   - PASSIVE
   

4. Parts of the vocal tract