Respiratory System Introduction Quiz

Respiratory System Overview

• The respiratory system has four major functions:
  • Supplies oxygen to the body
  • Disposes of carbon dioxide waste
  • Enables aerobic respiration in cells
  • Homeostatic regulation of body pH
  • Protection from inhaled pathogens and irritating substances
  • Sound production and sense of smell

Functional Anatomy of the Respiratory System

• The respiratory system consists of:
  • Nose and nasal cavity
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi and their smaller branches
  • Lungs and alveoli

Nose and Paranasal Sinuses

• The nose produces mucus, provides an airway for respiration, moistens and warms air, filters inhaled air, and houses olfactory receptors
• The olfactory mucosa is located near the roof of the nasal cavity and houses olfactory receptors
• Respiratory mucosa lines the nasal cavity and has a pseudostratified ciliated columnar epithelium with goblet cells
• The underlying layer of lamina propria has glands that contribute to the mucus layer and blood vessels that warm the air

Nasal Cavity

• Nasal conchae are three paired bony projections along the lateral walls of the nasal cavity
• Superior and middle nasal conchae are part of the ethmoid bone, while the inferior nasal conchae are a separate bone
• Function: to deflect particulate matter to mucus-coated surfaces

Paranasal Sinuses

• Four types of paranasal sinuses: frontal, sphenoid, ethmoid, and maxillary
• Located in the skull and function to produce mucus and lighten the skull

Pharynx

• The pharynx is a funnel-shaped passageway that connects the nasal cavity and mouth
• Shared by the digestive and respiratory systems
• Divided into three sections: nasopharynx, oropharynx, and laryngopharynx

Larynx

• The larynx prevents food and drink from entering the trachea and produces sound
• Connects the pharynx to the trachea
• Epithelium of the larynx is stratified squamous superiorly and pseudostratified ciliated columnar inferiorly
• Vocal ligaments of the larynx include the vocal folds (true vocal cords) and vestibular folds (false vocal cords)

Trachea

• The trachea has C-shaped cartilage rings that keep the airway open
• The carina marks where the trachea divides into two primary bronchi
• Epithelium of the trachea is pseudostratified ciliated columnar

Bronchial Tree

• The bronchial tree consists of the respiratory zone and conducting zone
• Respiratory zone: actual site of gas exchange, composed of respiratory bronchioles, alveolar ducts, and alveoli
• Conducting zone: includes all other respiratory passageways, providing rigid conduits for air to reach the gas exchange sites

Mechanics of Ventilation

• Pulmonary ventilation consists of two phases: inspiration and expiration
• Intrapulmonary pressure fluctuates with breathing and always eventually equalizes with atmospheric pressure
• Intrapleural pressure fluctuates with breathing and is always a negative pressure

Learn about the major functions of the respiratory system, including oxygen supply and carbon dioxide removal, and the processes involved in respiration.