respiratory

• Respiration


  Includes the following processes: 1) Ventilation, or breathing, which is the movement of air into and out of the lungs 2) The exchange of oxygen (O2) and carbon dioxide (CO2) between the air in the lungs and the blood 3) The transport of O2 and CO2 in the blood 4) The exchange of O2 and CO2 between the blood and the tissues

  
• Functions of the respiratory system

  • Respiration
  • Regulation of blood pH
  • Voice Production
  • Olfaction
  • Innate Immunity

  
• Upper respiratory tract


  External nose, Nasal cavity, Pharynx

  
• The external nose is composed mainly of hyaline cartilage
• Nasal cavity


  Extends from nares (nostrils) to choana, choana are openings to pharynx, hard palate is its roof

  
• Paranasal sinuses


  Air filled spaces within bone, open into nasal cavity, lined with mucous

  
• Conchae

  On each side of nasal cavity, increase surface area of nasal cavity, help in cleaning, humidifying, warming of air
• Nasolacrimal ducts


  Carry tears from eyes, open into nasal cavity
• Functions of the nose

  • Filters
  • Airway for respiration
  • Involved in speech
  • Olfactory receptors
  • Warms air
  • Sneezing dislodges materials from nose
• Pharynx


  A common passageway for the respiratory and digestive systems, consists of nasopharynx, oropharynx, and laryngopharynx

  
• Uvula


  "Little grape", extension of soft palate
• Pharyngeal tonsil


  Aids in defending against infections
• The lower respiratory tract includes the larynx, trachea, bronchi, and lungs

  
• Larynx


  Located in the anterior throat and extends from the base of the tongue to the trachea, consists of cartilages including the thyroid cartilage (Adam's apple) and the epiglottis

  
• Vocal folds/cords


  Source of voice production, air moves past them, they vibrate, and sound is produced, force of air determines loudness, tension determines pitch
• Laryngitis


  Inflammation of vocal folds, caused by overuse, dry air, infection
• Trachea


  Windpipe, consists of 16 to 20 C-shaped pieces of cartilage, contains cilia pseudostratified columnar epithelium, smoking kills cilia, coughing dislodges materials from trachea, divides into right and left primary bronchi (lungs)
• Bronchi


  Divide from trachea, connect to lungs, lined with cilia, contain C-shaped pieces of cartilage
• Lungs


  Primary organ of respiration, cone shaped, the base rests on the diaphragm, the apex extends above the clavicle, right lung has 3 lobes, left lung has 2 lobes, contains many air passageways (divisions)

  
• Lung airway passages


  • Primary bronchi
  • Lobar (secondary) bronchi
  • Segmental (tertiary) bronchi
  • Bronchioles
  • Terminal bronchioles
  • Respiratory bronchioles
  • Alveolar ducts
  • Alveoli

  
• Alveoli


  Small air sacs where gas exchange occurs, surrounded by capillaries, 300 million in lungs

  
• Asthma attack


  Contraction of terminal bronchioles leads to reduced air flow
• Respiratory membrane


  In lungs where gas exchange between air and blood occurs, formed by walls of alveoli and capillaries, alveolar ducts and respiratory bronchioles also contribute, very thin for diffusion of gases

  
• Pleura


  Double-layered membrane around lungs, parietal pleura lines thoracic cavity, visceral pleura covers lung's surface, pleural cavity is the space around each lung

  
• Ventilation (breathing)


  A process of moving air in and out of the lungs, uses the diaphragm, which is a skeletal muscle that separates the thoracic and abdominal cavities

  
• Phases of ventilation


  • Inspiration (breathe in, uses diaphragm and external intercostal muscles)
  • Expiration (breathe out, uses diaphragm)
  • Forceful expiration (uses internal intercostal muscles)

  
• When thoracic cavity volume increases

  Pressure decreases
• When thoracic cavity volume decreases


  Pressure increases
• Inspiration


  Diaphragm descends and rib cage expands, thoracic cavity volume increases, pressure decreases, atmospheric pressure is greater than alveolar pressure, air moves into alveoli (lungs)
• Expiration


  Diaphragm relaxes and rib cage recoils, thoracic cavity volume decreases, pressure increases, alveolar pressure is greater than atmospheric pressure, air moves out of lungs

  
• Lung recoil


  Tendency for an expanded lung to decrease in size, occurs during quiet expiration, due to elastic fibers and thin film of fluid lining alveoli
• Surfactant


  A mixture
• Inspiration


  1. Diaphragm descends and rib cage expands

  2. Thoracic cavity volume increases, pressure decreases

  3. Atmospheric pressure is greater than (high) alveolar pressure (low)

  4. Air moves into alveoli (lungs)
• Expiration


  1. Diaphragm relaxes and rib cage recoils

  2. Thoracic cavity volume decreases, pressure increases

  3. Alveolar pressure is greater than (high) atmospheric pressure (low)

  4. Air moves out of lungs

  
• Air flows from areas of high to low pressure
• Lung recoil


  • The tendency for an expanded lung to decrease in size
  • Occurs during quiet expiration
  • Due to elastic fibers and thin film of fluid lining alveoli
• Surfactant


  • A mixture of lipoproteins
  • Produced by secretory cells of the alveoli
  • A single fluid layer on the surface of thin fluid lining alveoli
  • Reduces surface tension
  • Keeps lungs from collapsing
• Pleural pressure


  • Pressure in the pleural cavity
  • Less than alveolar pressure
  • Keeps the alveoli from collapsing
• Factors that influence pulmonary ventilation

  • Lung elasticity
  • Lung compliance
  • Respiratory passageway resistance

  
• Spirometer


  Device that measures pulmonary volumes