· Pharynx OH-ADAM

Is the common opening of the digestive and respiratory systems.
- Receives air from the nasal cavity and air, food and water from the mouth.
Inferiorly, the pharynx leads to separate openings of the respiratory system (larynx) and digestive system (esophagus).
Pharynx can be divided into three (3) regions:
- Nasopharynx
- Oropharynx
- Laryngopharynx
Nasopharynx
- Is the superior region of the pharynx and extends from the external nares to the level of the uvula--a soft process that extends from the posterior edge of the soft palate.
- Is lined with a mucous membrane.
- Auditory tubes open here.
- Posterior surface contains the pharyngeal tonsil that protects the body from infection.
Oropharynx
- Extends from the uvula to the epiglottis.
- Oral cavity opens into the oropharynx through the fauces.
  - Food, drink, and air pass through the oropharynx.
- Is lined with stratified squamous epithelium that provides protection against abrasion.
- Two (2) sets of tonsils (palatine and lingual) are located near the fauces.
Laryngopharynx
- Extends from the tip of the epiglottis to the openings of the larynx and esophagus.
- Is lined with squamous epithelium.

Consists of an outer casing of nine (9) cartilages connected to each other by muscles and ligaments.
- Six (6) of the cartilages are paired and three (3) are unpaired. 23316

Largest and most superior of the cartilages is the thyroid cartilage or Adam's Apple.
Most inferior cartilage is the unpaired cricoid cartilage which forms the base of the larynx on which the others rest.
Third unpaired cartilage is the epiglottis.
- Consists of elastic cartilage rather than hyaline.
- During swallowing the epiglottis covers the opening of the larynx and prevents material from entering the larynx.
Six (6) paired cartilages are stacked in two pillars between the cricoid and thyroid cartilages.

Arytenoid cartilages--largest--most inferior.
Corniculate cartilages--middle pair.
Cuneiform cartilages--Most superior and smallest.
- Two (2) pairs of ligaments extend from the anterior surface of the arytenoid cartilages to the posterior surface of the thyroid cartilage.

Superior pair forms the vestibular folds or false vocal cords. OH-ADAM
- When the vestibular folds come together, they prevent air from coming from the lungs and prevent food and liquids from entering the larynx.
Inferior pair of ligaments form the vocal cords or true vocal cords. 23329

The true vocal cords and the opening between them is called the glottis.
The vestibular folds and the vocal cords are lined with stratified squamous epithelium.
Remainder of the larynx is lined with pseudostratified ciliated columnar epithelium.
Inflammation of the mucosal epithelium of the vocal cords is called laryngitis.
- When speech is produced, air moving past the vocal cords causes them to vibrate producing sound. 23545 Play, 23737 Play, 23821 Play, 24187 Play
The greater the amplitude of the vibration, the louder the sound will be.
Pitch is controlled by the frequency of the vibrations.
- The cricoid cartilage and the arytenoid cartilages can be moved by various muscles to change the length of the vocal cords.
  - Higher pitched tones are produced when only the anterior portions of the cords vibrates.
Progressively lower tones result when longer sections of the cords vibrate.
- Males normally have lower voices than females because males usually have longer vocal cord.
- The sound produced by the vibrating vocal cords is modified by the tongue, lips, and teeth to form words.
- People with the larynx removed can produce sound by swallowing air and causing the esophagus to vibrate

Is a membraneous tube that consists of dense regular connective and smooth muscle reinforced with 15-20 "C"-shaped pieces of cartilage.
- Cartilages form the anterior and lateral sides.
  - Protect the trachea and maintain an open passageway for air.
Posterior wall contains no cartilage and consists of a ligamentous membrane and smooth muscle which can alter the diameter of the trachea.
- Esophagus lies immediately posterior to the cartilage-free posterior wall of the trachea.
Trachea is lined with pseudostratified ciliated columnar epithelium that contains numerous goblet cells. 23293

Cilia propel mucus and foreign particles toward the larynx where they can enter the esophagus and be swallowed. 23325, 23326

Right bronchus is shorter and wider and is more vertical than the left bronchus.
Primary bronchi extend from the mediastinum to the lungs.
The lining of the bronchi is the same as the trachea and the bronchi are supported by "C"-shaped cartilage rings.