Functions and Anatomy of the Respiratory System

Study Notes

Functions of the Respiratory System

Exchanges oxygen (O₂) and carbon dioxide (CO₂) between air and blood.
Regulates blood pH, maintaining acid-base balance.
Assists in sound production through vocal cord vibration.
Conducts air over sensory receptors, enhancing the sense of smell.
Provides protection against pathogens through filtering and immune responses.

Anatomy of the Respiratory System

Nose

Composed of external nose and nasal cavity; the external structure is largely cartilage.
The nasal cavity functions to warm, humidify, and clean inhaled air.
Nares (nostrils) lead to the pharynx; the cavity divided by nasal septum into left and right sections.
Paranasal sinuses and the nasolacrimal duct open into the nasal cavity.
Nasal hairs trap debris, while the lining contains pseudostratified epithelium with cilia that move trapped particles toward the pharynx.

Pharynx

Nasopharynx connects to nasal cavity via choanae; contains the auditory tube opening and pharyngeal tonsils.
Oropharynx connects to the oral cavity; houses palatine and lingual tonsils.
Laryngopharynx opens into the larynx and esophagus, facilitating the passage of air and food.

Larynx

Made up of three unpaired and six paired cartilages; thyroid and cricoid cartilages are the most prominent.
Epiglottis serves as a flap covering the laryngeal opening during swallowing to prevent aspiration.
Vestibular folds protect the larynx by blocking airflow and food.
Vocal folds (true vocal cords) vibrate with airflow to produce sound; air pressure affects loudness, while fold tension alters pitch.

Trachea

Serves as a conduit connecting the larynx to the primary bronchi.

Bronchi

Main bronchi branch out from the trachea into each lung, providing airway entry.

Lungs

Consist of two organs; airway passages decrease in size as they branch.
Main bronchi divide into lobar bronchi for each lung lobe, then segmental bronchi for each bronchopulmonary segment.
Segmental bronchi further branch into smaller bronchioles, leading to terminal bronchioles, which connect to alveolar ducts.
Alveoli are clusters of air sacs adjacent to alveolar ducts, facilitating gas exchange.
The epithelial layer from the trachea to terminal bronchioles is ciliated for debris removal.
Cartilage maintains airway structure, while smooth muscle regulates tube diameter (notably in bronchioles).
The alveoli consist of simple squamous epithelium, optimizing gas diffusion.
The respiratory membrane consists of six thin layers, ensuring efficient gas exchange and a large surface area for maximum diffusion.

Description

Explore the vital functions of the respiratory system, including gas exchange and pH regulation. Understand the anatomical structure, such as the nose and nasal cavity, and how they contribute to overall respiratory health.