Upper Respiratory System

Definition
The upper respiratory system consists of the parts outside the chest cavity including:

• nasal cavity
• pharynx
• epiglottis
• larynx
• esophagus
• trachea
  

The upper respiratory system changes with growth. Children's airways are smaller and shorter.

• Child's epiglottis is floppier and U-shaped.
• Child's airway is anterior and higher.
• Child's trachea is more flexible.
  

• Airway muscles and cartilage are not completely developed. This makes it easier for the airways to collapse.
• Small amounts of mucus or swelling can greatly decrease the radius of the airway, increasing resistance to airflow and the work of breathing.
• One mm of edema increases the resistance in an infant's airway by a factor of 16 versus a factor of 2.4 in an adult airway.