Chapter 19 – Respiratory System

Pharynx and Larynx

Pharynx

• Throat– Located posterior to oral cavity, between the nasal

cavity and the larynx– Has 3 divisions• nasopharynx, oropharynxx, and laryngopharynx

Pharynx

• Functions:– Serves as a passageway for food moving from the

oral cavity to the esophagus – Serves as a passageway for air passing between

the nasal cavity and the larynx– Aids in producing sounds for speech

Larynx

• Enlargement of the airway between the trachea and the pharynx

Larynx

• Functions– Serves as a passageway for air moving into and

out of the trachea– Prevents foreign objects from entering the trachea– Houses the vocal cords

Larynx

• Structure– Composed of muscles and cartilages that are

bound by elastic tissue• Single cartilages (largest):

– Thyroid, cricoid, and epiglottic cartilages

• Paired cartilages:– Arytentoid, corniculate, and cuneiform cartilages

Larynx• Structure– Thyroid cartilage• Lower portion is covered by the thyroid gland• Commonly called the Adam’s apple • Is more prominent in males due to differences in

hormones

Larynx

• Structure– Cricoid cartilage• Inferior to the thyroid cartilage• Marks the lowest portion of the larynx

Larynx

• Structure– Epiglottic cartilage• Attached to the upper border of the thyroid cartilage• Supports the epiglottis

Larynx

• Structure– Arytenoid cartilages• Superior to and on either side of the cricoid cartilage

Larynx• Structure– Corniculate cartilages• Attached to the tips of the arytenoid cartilages• Serve as attachments for muscles that help regulate

tension on the vocal cords during speech and aid in closing the larynx during swallowing

Larynx

• Structure– Cuneiform cartilages• Located in the mucous membrane between the

epiglottic and arytenoid cartilages• Stiffen soft tissues

Larynx

• Structure– False vocal cords (vestibular folds)• Horizontal folds of muscle and connective

tissue covered by mucous membrane that extend inward from the lateral walls of the larynx• Help to close the larynx during swallowing

– During swallowing, muscles close the triangular shaped opening (called the glottis) between the vocal cords

Larynx• Structure– True vocal cords• Horizontal folds of muscle and connective tissue

covered by mucous membrane that extend inward from the lateral walls of the larynx• Located below the false vocal cords• Contain elastic fibers that vibrate from side to side

when air is forced between the folds– The vibration produces sound waves that can be formed

into words through changes in shape and position of the pharynx, oral cavity, tongue, and lips

Larynx

• Structure– True vocal cords• Pitch (musical tone)

– Controlled by the amount of tension placed on the vocal cords by laryngeal muscles (ncreased tension causes higher pitch)

• Intensity (loudness)– Depends on the force of the air passing over the vocal cords

(stronger force creates greater vibrations and louder voice)