Structures to know: Respiratory System

Respiratory System Overview

Major Components

  • Nares: Entry points for air into the respiratory system.

  • Nasal Cavity: Air passage that filters, warms, and humidifies air.

  • Nasal Fossae: The two cavities within the nasal cavity that aid in airflow and olfaction.

  • Soft Palate: The flexible back portion of the roof of the mouth, aiding in swallowing and breathing.

  • Hard Palate: The bony front part of the roof of the mouth that forms a barrier between the nasal cavity and the mouth.

  • Epiglottis: A flap that covers the trachea during swallowing, preventing food from entering the airway.

  • Pharynx: A muscular tube that connects the nasal cavity and mouth to the larynx and esophagus, divided into:

    • Nasopharynx: Upper part behind the nose.

    • Oropharynx: Mid part behind the mouth.

    • Laryngopharynx: Lowest part that leads to the larynx and esophagus.

  • Larynx: The voice box containing structures such as:

    • Epiglottis: As mentioned above.

    • Hyoid Bone: A U-shaped bone in the neck that supports the tongue.

    • Laryngeal Prominence: The Adam's apple, indicating the location of the thyroid cartilage.

    • Cricoid Cartilage: A ring of cartilage that supports the larynx.

Lower Respiratory Tract

  • Trachea: The windpipe that conducts air to the bronchi.

  • Pleura: Membranes surrounding the lungs, including:

    • Visceral Pleura: Inner layer covering the lungs.

    • Parietal Pleura: Outer layer lining the chest cavity.

    • Pleural Cavity: Space between the two pleura that contains pleural fluid.

  • Lungs: Organs for gas exchange, with:

    • Apex: The top part of the lung.

    • Base: The bottom part of the lung.

    • Right Lung: Consists of three lobes—superior, middle, inferior.

    • Left Lung: Consists of two lobes—superior, inferior.

    • Oblique Fissure: Separates the lobes of the left lung.

    • Horizontal Fissure: Separates the lobes of the right lung.

    • Hilum: The region where structures enter and leave the lung.

    • Cardiac Impression: An indentation in the left lung due to proximity to the heart.

  • Diaphragm: A muscular structure that aids in breathing by contracting and relaxing.

Bronchial Tree

  • Trachea: Main airway leading to the lungs.

  • Carina: The ridge at the base of the trachea that splits into the left and right main bronchi.

  • Right/Left Main Bronchi: The two primary branches that carry air into each lung respectively.

  • Lobar Bronchi: Branches that serve each lung lobe (one for each lobe).

  • Segmental Bronchi: Further subdivisions from lobar bronchi.

  • Conducting Bronchioles: Smaller airways that lead to terminal bronchioles.

  • Terminal Bronchioles: The smallest air passages in the lungs just before reaching the alveoli.

  • Alveoli: Tiny air sacs where gas exchange occurs.