Lesson 4: Respiratory System (Textbook p. 88)

Freedom is having a word for things.

Respiration (breathing) is inhaling oxygen and exhaling carbon dioxide.

In The Lesson

In Lesson 4, you are introduced to the respiratory system made up of two parts the:

  • upper respiratory tract – nose, pharynx, and larynx
  • lower respiratory tract – trachea, bronchi, and lungs

Adam’s Apple

Adam’s apple is the largest ring of cartilage on the larynx, also known as the thyroid cartilage. The name came from the belief that Adam realizing he had sinned when he ate the forbidden fruit, could not swallow the apple lodged in his throat.