Anatomy & Physiology Respiratory #6


Which respiratory structure is responsible for the absorption of oxygen from the atmosphere into the blood?


  1. Trachea
    • Rationale:

      While the trachea is a structure of the lower respiratory tract, it is not the structure responsible for gas exchange. The trachea connects the pharynx to the larynx.

  2. Alveoli
    • Rationale:

      The alveoli are the structure in the lower respiratory tract that performs gas exchange. The gases exchanged during this process are oxygen and carbon dioxide.

  3. Pulmonary vein
    • Rationale:

      Arteries are structures of the circulatory, not respiratory, system. The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.

  4. Pulmonary artery
    • Rationale:

      Veins are structures of the circulatory, not respiratory, system. The pulmonary vein carries oxygenated blood from the lungs to the heart.


Gas exchange in the process where oxygen is absorbed from the atmosphere into the blood. In addition, gas exchange also includes the exchange of carbon dioxide from the blood to the respiratory system for expiration.


Learning Outcomes

The alveoli are the air sacs in the lungs. They are the site where physiological gas exchange takes place. The physiological exchange of gases includes both carbon dioxide and oxygen.

Test Taking Tip

Eliminate wrong answers! Consider each answer choice and determine if all are respiratory structures. If they are not, eliminate them as correct answer choices.

Video Rationale