Respiratory

• Respiratory System


  The set of organs that allows a person to breathe and exchange oxygen and carbon dioxide throughout the body
• Respiratory System


  • Integrated system of organs involved in the intake and exchange of oxygen and carbon dioxide between the body and the environment
  • Includes the nasal passages, larynx, trachea, bronchial tubes, and lungs
• Functions of Respiratory System

  1. Supplies the body with oxygen and disposes of carbon dioxide

  2. Filters inspired air

  3. Produces sound

  4. Contains receptors for smell

  5. Rids the body of some excess water and heat

  6. Helps regulate blood pH
• Breathing (Pulmonary Ventilation)


  1. Inhalation (inspiration) - draws gases into the lungs

  2. Exhalation (expiration) - forces gases out of the lungs
• External Respiration


  Air from the outside environment enters the nose or mouth during inspiration (inhalation)
• Nose and Nasal Cavities

  • Also called external nares
  • Divided into two halves by the nasal septum
  • Contains the paranasal sinuses where air is warmed
  • Contains cilia which is responsible for filtering out foreign bodies
• Nasopharynx


  Contains the pharyngeal tonsils (adenoids) which aid in the body's immune defense
• Oropharynx


  Back portion of the mouth that contains the palatine tonsils which aid in the body's immune defense
• Laryngopharynx


  Bottom section of the pharynx where the respiratory tract divides into the esophagus and the larynx
• Larynx


  • Voice box is a short, somewhat cylindrical airway that ends in the trachea
  • Prevents swallowed materials from entering the lower respiratory tract
  • Conducts air into the lower respiratory tract
  • Produces sounds
  • Supported by a framework of nine pieces of cartilage
• Trachea


  • A flexible tube also called windpipe
  • Extends through the mediastinum and lies anterior to the esophagus and inferior to the larynx
  • Cartilage rings reinforce and provide rigidity to the tracheal wall to ensure that the trachea remains open at all times
  • At the level of the sternal angle, the trachea bifurcates into two smaller tubes, called the right and left primary bronchi
• Lungs


  • Each lung has a conical shape with a wide, concave base resting upon the muscular diaphragm
  • Both lungs are bordered by the thoracic wall anteriorly, laterally, and posteriorly, and supported by the rib cage
  • Toward the midline, the lungs are separated from each other by the mediastinum
  • The relatively broad, rounded surface in contact with the thoracic wall is called the costal surface of the lung
• Lung Lobes


  • Left lung - divided into 2 lobes by oblique fissure, smaller than the right lung, has a cardiac notch
  • Right lung - divided into 3 lobes by oblique and horizontal fissure, located more superiorly in the body due to liver on right side
• Pleura


  • The outer surface of each lung is tightly covered by the visceral pleura
  • The internal thoracic walls, the lateral surfaces of the mediastinum, and the superior surface of the diaphragm are lined by the parietal pleura
  • The parietal and visceral pleural layers are continuous at the hilus of each lung
• Pleural Cavities


  • The potential space between the serous membrane layers
  • The pleural membranes produce a thin, serous pleural fluid that circulates in the pleural cavity and acts as a lubricant, ensuring minimal friction during breathing
• How Lungs Work


  1. Air enters lungs through bronchi

  2. Alveoli are where gas exchange takes place between air and blood

  3. Alveoli and capillaries are very close together to allow oxygen and carbon dioxide to diffuse

  4. Oxygen from fresh air in alveoli diffuses into blood stream

  5. Carbon dioxide from blood diffuses into alveoli and is breathed out
• Breathing


  1. During inhalation, the diaphragm contracts and the rib cage rises up, expanding the volume of the chest cavity and creating a partial vacuum that draws air into the lungs

  2. During exhalation, the rib cage lowers and the diaphragm relaxes, increasing pressure in the chest cavity and pushing air out of the lungs