Respiratory System

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Respiratory System
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Respiration

• The process of exchanging oxygen and carbon
  dioxide with the external environment.
• Gases are products and reactants in cellular
  respiration
• Cellular respiration provides cells with energy
  in the form of ATP.
• Adenosine Triphosphate

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Stages of Respiration

• Breathing
• Inspiration - breathing in
• Expiration - breathing out
• Ventilation - encompasses inspiration and
  expiration
• External Respiration
• Exchange of gases between the air and the blood
• Occurs in the alveoli

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Stages of Respiration contd

• Internal Respiration
• Exchange of O2 and CO2 with the blood and cells
• Occurs in the capillary beds
• Cellular Respiration
• Production of ATP within the cells
• Occurs in the mitochondria

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The Respiratory Tract

• Fig. 15.1

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Upper Respiratory Tract Nasal Cavity

• Main entry point for air.
• Preferred over the oral cavity
• Contains 2 nasal cavities
• Communicate with sinuses
• Lined by mucous membrane
• Bony ridges increase surface area

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Upper Respiratory Tract Nasal Cavity contd
Fig. 15.2

• Functions
• 1) Warms air - heat from vessels
• 2) Cleanses air - coarse hairs and mucus
• 3) Humidifies air - wet surfaces of membrane
• Olfactory receptors - on cilia high up in nasal
  cavities
• Lacrimal glands drain into nasal cavity

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Upper Respiratory Tract Pharynx

• Connects nasal and oral cavities to larynx
• Tonsils form a protective ring at this point
• 3 divisions
• Nasopharynx
• Nasal cavities open posterior to soft palate
• Oropharynx
• Where oral cavity opens
• Uvula projects into oropharynx
• Laryngopharynx
• Opens into larynx

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Upper Respiratory Tract Larynx

• Passageway for air between pharynx and trachea
• Protected by a thick band of cartilage
• known as the Adams apple
• Have vocal cords
• Folds of mucosa
• Glottis-opening between folds
• Supported by elastic ligaments
• Vibrate during exhalation
• Pitch controlled by tension
• Higher tension higher pitch
• Loudness controlled by amplitude of vibration

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Upper Respiratory Tract Larynx contd

• Epiglottis
• Prevents food from entering during swallowing
• Larynx and trachea are normally open, when you
  swallow larynx moves up to and closes.
• Esophagus is normally closed

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Placement of the Vocal Chord

• Fig. 15.3