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    Anatomy of the Respiratory System


    Respiration is the act of breathing:

    • Inhaling. The act of breathing in oxygen.

    • Exhaling. The act of breathing out carbon dioxide.

    Respiratory system

    Illustration of the human respiratory system
    Respiratory System - Click to Enlarge

    The respiratory system is made up of the organs included in the exchange of oxygen and carbon dioxide. These are the parts:

    • Nose

    • Mouth

    • Throat (pharynx)

    • Voice box (larynx)

    • Windpipe (trachea)

    • Large airways (bronchi)

    • Lungs

    The upper respiratory tract is made up of the:

    • Nose

    • Nasal cavity

    • Sinuses

    • Larynx

    • Trachea

    The lower respiratory tract is made up of the:

    • Lungs

    • Bronchi and bronchioles

    • Air sacs (alveoli)


    The lungs take in oxygen. The cells of your body's cells need oxygen to live and carry out their normal functions. The lungs also get rid of carbon dioxide, a waste product of the cells.

    The lungs are a pair of cone-shaped organs made up of spongy, pinkish-gray tissue. They take up most of the space in the chest (thorax).

    The lungs are surrounded by a membrane (pleura).

    The lungs are separated from each other by the mediastinum, an area that contains the:

    • Heart and its large vessels

    • Trachea

    • Esophagus

    • Thymus gland

    • Lymph nodes

    The right lung has 3 sections, called lobes. The left lung has 2 lobes. When you breathe:

    • Air enters your body through your nose or mouth.

    • Air then travels down the throat through the larynx and trachea.

    • Air goes into the lungs through tubes called main-stem bronchi.

    One main-stem bronchus leads to the right lung and one to the left lung:

    • In the lungs, the main-stem bronchi divide into smaller bronchi.

    • The smaller bronchi divide into even smaller tubes (bronchioles).

    • Bronchioles end in tiny air sacs (alveoli) where the exchange of oxygen and carbon dioxide occurs.

    Online Medical Reviewer: Alan J Blaivas DO
    Online Medical Reviewer: Daphne Pierce-Smith RN MSN CCRC
    Online Medical Reviewer: John Hanrahan MD
    Date Last Reviewed: 3/1/2019
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