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Anatomy of the Respiratory System

Respiration

Respiration is the act of breathing:

  • Inhaling (inspiration). The act of breathing in oxygen.

  • Exhaling (expiration). 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 involved in the exchange of oxygen and carbon dioxide, and consists of the:

  • Nose

  • Mouth

  • Pharynx (throat)

  • Larynx (voice box)

  • Trachea (windpipe)

  • Bronchi (large airways)

  • Lungs

The upper respiratory tract includes the:

  • Nose

  • Nasal cavity

  • Sinuses

  • Larynx

  • Trachea

The lower respiratory tract includes the:

  • Lungs

  • Bronchi and bronchioles

  • Alveoli (air sacs)

Lungs

The lungs take in oxygen, which the body's cells need 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, or the thorax.

The lungs are surrounded by a membrane called the pleura.

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

  • Heart and its large vessels

  • Trachea (windpipe)

  • Esophagus

  • Thymus gland

  • Lymph nodes

The right lung has three sections, called lobes. The left lung has two lobes. When you breathe, the air:

  • Enters the body through the nose or the mouth

  • Travels down the throat through the larynx (voice box) and trachea (windpipe)

  • 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

    • And then into even smaller tubes called bronchioles

    • Bronchioles end in tiny air sacs called alveoli

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