Respiratory System

• Respiratory System 

  Primary function: to supply the body’s need for oxygen and to give off carbon dioxide
• Respiratory System 

  Other functions: 

  • Maintaining homeostasis and a normal pH
  • Participating in the body’s immune defense against bacterial and viral infections
• Respiratory System 

  Primary function: to supply the body’s need for oxygen and to give off carbon dioxide
• Respiratory System

  Other functions: 

  • Maintaining homeostasis and a normal pH
  • Participating in the body’s immune defense against bacterial and viral infections
• Classification based on Anatomy

  1. Upper respiratory airway (URA)
  2. Lower respiratory airway (LRA)
• Classification based on Function

  1. Conducting portion
  2. Respiratory portion
• • Conducting portion consists of upper respiratory airway and lower respiratory airway
• • Conducting portion consists of upper respiratory airway and lower respiratory airway
  • Includes nasal cavity, pharynx, larynx, trachea, extrapulmonary and intrapulmonary bronchi, bronchioles, and terminal bronchioles
  • Transportation of gasses (oxygen and CO2), keep warm and clean
• Respiratory portion

  • Includes respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli
  • Mostly the exchange of gasses
• CONDUCTING PORTION – URA

  Upper Respiratory Airway consist of:

  • Nasal cavity
  • Nasopharynx
  • Oropharynx 
  • Larynx
• • Nasal cavity lined with ciliated epithelium rich in mucus (trap particles inhaled)
  • Roof of the cavity has olfactory nerve cell lining responsible for the sense of smell
• • Nasal cavity lined with ciliated epithelium rich in mucus (trap particles inhaled)

  Roof of the cavity has olfactory nerve cell lining responsible for the sense of smell
• Nasal conchae - has three major regions; foldings increasing the surface area of the nasal cavity
• • Nasal conchae - has three major regions; foldings increasing the surface area of the nasal cavity

  1. Inferior conchae - bottom
  2. Middle conchae
  3. Superior conchae
• • Larynx closed by the epiglottis (above the larynx) when eating for the material to travel down the esophagus
• NASAL CAVITY 

  • The first portion of the upper respiratory airway
• • Nasal cavity - can be divided into three (3) regions based on the types of epithelial coverings

  1st Region: Nasal Vestibule

  2nd Region: Nasal Mucosa Region

  3rd Region: Olfactory Mucosa Region
• 1st Region: Nasal Vestibule

  • Most anterior part of the nasal cavity

  Covered by keratinized stratified squamous epithelium and vibrissae (stiff hairs)
• 2nd Region: Nasal Mucosa Region

  Covered by pseudostratified ciliated columnar epithelium (respiratory epithelium), which contains ciliated columnar cells, goblet cells, basal cells, and occasionally, neuroendocrine cells
• Goblet cells - secreting mucus and serous fluid trapping fluids
• 3rd Region: Olfactory Mucosa Region

  • Located in the roof of the nasal cavity is covered by pseudostratified columnar epithelium, which is composed of ciliated olfactory cells (olfactory receptor neurons), non-ciliated columnar cells, and basal cells
• Olfactory Mucosa Region

  • Functions as a site for odorant chemoreception (physiological process whereby organisms respond to chemical stimuli)
• Olfactory Mucosa Region

  • Olfactory receptor neurons - bipolar neurons activated when air-borne in inspired or inhaled air bind into the receptors (cilia)
• NASOPHARYNX AND OROPHARYNX 

  • NP and OP conduct air from  the nasal cavity and oral cavity to the larynx respectively
• • Pharyngeal tonsil an unencapsulated patch of lymphoid tissue, is located in the posterior aspect of the nasopharynx
• • Palatine tonsils located at the junction of the oral cavity and the oral pharynx 
• LARYNX

  • Conducts air from the pharynx to the trachea
  • Supported by a set of cartilages of complex shape and covered by a ciliated, pseudostratified respiratory epithelium
• Epiglottis

  Thin-leaf like plate structure; its central cord contains a large piece of elastic cartilage
• Epiglottis

  • Stands in front of the laryngeal inlet and bends posteriorly to cover the inlet of the larynx when food is swallowed
• Epiglottis

  • Thin-leaf like plate structure; its central cord contains a large piece of elastic cartilage

  The upper anterior surface of the epiglottis is covered by a non-keratinized stratified squamous epithelium
• Vocal Cords

  • Contain striated skeletal muscle and ligaments (mainly elastic fibers)
  • Lined by nonkeratinized stratified squamous epithelium, which firmly attached to the underlying vocal ligaments
  • The stratified squamous epithelium protects the vocal cords from mechanical stress 
• Vocal Cords

  The main functions of the vocal cords are to control airflow and facilitate speaking
• CONDUCTING PORTION – LRA

  Lower Respiratory Airway

  • Includes the trachea, bronchi, bronchioles, and terminal bronchioles
  • Each portion of the lower respiratory airway has unique tissue components, which facilitate oxygen delivery, gas exchange, and immune defense mechanisms
  • Individual airways decrease in diameter as they continue branching
• Trachea - windpipe
• TRACHEA 

  • Tube formed of cartilage and fibromuscular membrane, 10 - 12 cm long, with a diameter of 2 to 2.5 cm
  • Horseshoe-shaped cartilage
• TRACHEA Lined by pseudostratified columnar epithelium reinforced by 10 to 12 C-shaped hyaline cartilage rings
• • TRACHEA Lined by pseudostratified columnar epithelium reinforced by 10 to 12 C-shaped hyaline cartilage rings
  • The epithelium is composed of several cell types including goblet cells, ciliated columnar cells, basal cells, and occasionally neuroendocrine cells, which are also called diffuse neuroendocrine system (DNES) cells
• TRACHEA A band of smooth muscle is located between the two ends of the C-shaped cartilage
• Trachealis muscle - smooth muscle
• EXTRAPULMONARY BRONCHI 

  • The primary bronchi, which begin at the bifurcation of the trachea and lead to the right and left lungs