Respiratory System

• Respiration


  1. Ventilation or breathing, movement of air into and out of the lungs

  2. Exchange of oxygen (O2) and carbon dioxide (CO2) between the air in the lungs and the blood

  3. Transport of O2 and CO2 in the blood

  4. Exchange of O2 and CO2 between the blood and the tissues
• Functions of Respiratory System

  • Alters blood pH by changing blood CO2 levels
  • Enables voice production
  • Enables olfaction (sense of smell)
  • Provides innate immunity by preventing microorganisms and pathogens from entering the body and removing them from respiratory surfaces

  
• Air movement past the vocal cords makes sound and speech possible
• The sensation of smell occurs when airborne molecules are drawn into the nasal cavity
• The respiratory system protects against some microorganisms and other pathogens, such as viruses, by preventing them from entering the body and by removing them from respiratory surfaces

  
• Nose


  • Consists of external nose and nasal cavity
  • Nares or nostrils are the external openings of the nose
  • Choanae are the openings into the pharynx
  • Nasal cavity extends from the nares to the choanae

  
• Nose: The Sinuses


  • Secrete mucus to protect against infection and humidify the air before it reaches the lungs
  • Keep the nose moist
• Sneeze reflex


  1. Dislodges foreign substances from the nasal cavity

  2. Sensory receptors detect the foreign substances, and action potentials are conducted along the trigeminal nerves to the medulla oblongata, where the reflex is triggered
• Pharynx


  • Throat
  • Common passageway for both the respiratory and digestive systems
  • Air, food, and water pass through
  • Includes the nasopharynx, oropharynx, and hypopharynx/laryngopharynx

  
• Larynx


  • Voicebox
  • Located in the anterior throat and extends from the base of the tongue to the trachea
  • Functions to maintain an open airway, protect the airway during swallowing, and produce the voice

  
• Types of cartilages in the Larynx

  • Epiglottis - elastic cartilage, protects the airway during swallowing
  • Thyroid - shield shape, Adam's apple
  • Cricoid - ring-shaped, base of the larynx
  • Arytenoid
  • Corniculate

  
• Trachea


  • Windpipe
  • Allows air to flow into the lungs
  • Cough reflex - contraction of the smooth muscle to narrow the diameter of the trachea
• Bronchi


  • Left or right main bronchi or primary bronchi
  • Foreign objects that enter the trachea usually lodge in the right main bronchus, because it is wider, shorter, and more vertical than the left main bronchus and is more in direct line with the trachea
• Lungs


  • Principal organs of the respiratory system
  • 3 lobes: superior, middle, and inferior

  
• Lungs


  • Alveoli - hollow sacs, small air-filled chambers where the air and the blood come into close contact
  • Asthma attack - contraction of the smooth muscle on the terminal bronchioles can result in greatly reduced airflow
• How is breathing regulated during exercise?
• The respiratory system plays a role in homeostasis
• Respiration


  1. Ventilation or breathing, movement of air into and out of the lungs

  2. Exchange of oxygen (O2) and carbon dioxide (CO2) between the air in the lungs and the blood

  3. Transport of O2 and CO2 in the blood

  4. Exchange of O2 and CO2 between the blood and the tissues
• Respiratory System


  • Can alter blood pH by changing blood CO2 levels
  • Enables voice production
  • Enables olfaction
  • Provides innate immunity
• Vocal cords


  Air movement past them makes sound and speech possible
• Olfaction


  Sensation of smell occurs when airborne molecules are drawn into the nasal cavity
• Innate immunity


  Respiratory system protects against microorganisms and other pathogens by preventing them from entering the body and removing them from respiratory surfaces

  
• Anatomy of Respiratory System

  • Nose
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi
  • Lungs

  
• Nose


  • Consists of external nose and nasal cavity
  • Nares or nostrils are external openings
  • Choanae are openings into the pharynx
  • Nasal cavity extends from nares to choanae

  
• Sinuses


  • Secrete mucus to protect against infection and humidify air
  • Keep nose moist
• Sneeze reflex


  1. Dislodges foreign substances from nasal cavity

  2. Sensory receptors detect foreign substances, action potentials conducted along trigeminal nerves to medulla oblongata where reflex is triggered
• Pharynx


  Throat, common passageway for respiratory and digestive systems

  
• Larynx


  • Voicebox, located in anterior throat, extends from base of tongue to trachea
  • Maintains open airway
  • Protects airway during swallowing
  • Produces voice

  
• Larynx cartilages


  • Epiglottis
  • Thyroid
  • Cricoid
  • Arytenoid
  • Corniculate

  
• Trachea


  • Windpipe, allows air flow into lungs
  • Cough reflex contracts smooth muscle to narrow trachea diameter

  
• Bronchi


  • Left and right main bronchi or primary bronchi
  • Foreign objects usually lodge in right main bronchus as it is wider, shorter, and more vertical than left
• Lungs


  • Principal organs of respiratory system
  • 3 lobes: superior, middle, inferior
  • Alveoli are hollow sacs, small air-filled chambers where air and blood come into close contact
  • Asthma attack causes contraction of smooth muscle on terminal bronchioles, greatly reducing airflow