Anatomy of the Respiratory System

Overview of Respiratory Pathways

The respiratory system is responsible for the intake of oxygen and the removal of carbon dioxide. It consists of a series of anatomical structures that facilitate the movement of air from the external environment to the alveoli, where gas exchange occurs.

• Nares: Also known as nostrils, these are the external openings of the nose that allow air to enter the nasal cavity.

• Nasal Vestibule: The area just inside the nostrils, lined with hairs that filter large particles from inhaled air.

• Nasal Aperture: The opening leading from the nasal vestibule into the nasal cavity.

• Nasal Cavity: The space inside the nose where air is warmed, humidified, and filtered.

• Nasopharynx: The upper part of the pharynx, connecting the nasal cavity to the oropharynx.

• Oropharynx: The middle part of the pharynx, located behind the oral cavity.

• Laryngopharynx: The lower part of the pharynx, leading to the larynx and esophagus.

• Larynx: Also known as the voice box, it houses the vocal folds and is involved in sound production and protecting the airway during swallowing.

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

• Vocal Folds: Also called vocal cords, these are responsible for sound production.

• Trachea: The windpipe, a tube that conducts air from the larynx to the bronchi.

• Carina: The ridge at the base of the trachea where it divides into the primary bronchi.

• Primary Bronchus: The first branches of the trachea, leading into each lung.

• Secondary Bronchus: Branches of the primary bronchi that lead to each lobe of the lungs.

• Tertiary Bronchus: Smaller branches of the secondary bronchi, supplying air to specific segments of the lungs.

• Bronchioles: The smallest branches of the bronchial tree, leading to the alveolar ducts.

• Alveolar Duct: Small passages that connect bronchioles to alveolar sacs.

• Alveoli: Tiny air sacs where gas exchange occurs between air and blood.

Key Functions and Examples

• Filtration: Nasal hairs and mucosa filter dust and pathogens from inhaled air.

• Humidification: The nasal cavity adds moisture to the air, protecting delicate lung tissues.

• Protection: The epiglottis prevents food from entering the airway during swallowing.

• Gas Exchange: Occurs in the alveoli, where oxygen diffuses into the blood and carbon dioxide is expelled.

Additional info:

• The respiratory tract is divided into the upper (nose, pharynx, larynx) and lower (trachea, bronchi, bronchioles, alveoli) respiratory tracts.

• Each bronchus further divides into smaller bronchioles, increasing surface area for gas exchange.