Respiratory System

Organs of the Respiratory System:

1. Nose


  • Nostrils are openings for air.

  • Nose hairs protect the nasal cavity from large particles.

2. Nasal Cavity


  • Nasal Septum

  • Nasal Conchae


  • Support mucous membrane, which acts as filters.

  • Houses olfactory receptors.

  • Conducts air to and from the nasopharynx.

3. Sinus


  • Reduces the weight of the skull.

  • Acts as resonant chambers of the voice.

4. Pharynx


  • Passageway for air moving between the nasal cavity and the larynx.

5. Larynx


  • Passageway for air moving in and out the trachea.

  • Prevents objects from entering the trachea.

  • Holds vocal cords.


  • Muscle and cartilage.

  • False Vocal Cords: Helps close the larynx during swallowing.

  • True Vocal Cords: Responsible for vocal sounds.

6. Trachea


  • Filter air.

  • Passageway for air only.

7. Bronchial Tree

  • Filters air.

  • Distributes air to the alveoli (air sacs) where gas exchange happens.

2 secondary bronchials.

Branches of the Bronchial Tree

  1. Primary, secondary, tertiary bronchii

  2. bronchioles

  3. terminal bronchioles.

  4. Respiratory bronchioles: first structure that can exchange gas.

  5. Alveolar ducts

  6. alveolar sacs

  7. alveoli

8. Lungs

  • Houses bronchial tree, blood vessels, connective tissue, lymphatic vessels, and nerves.


  • Rights lung: 3 lobes – superior, middle, and inferior.

  • Left lung: 2 lobes – superior and inferior.