Respiratory System

• The respiratory system - consists of the structures used to acquire oxygen (O2) and remove carbon dioxide (CO2) from the blood.
• Functions of the Respiratory System:

  • Gas exchange or Respiration
  • Regulation of body pH
  • Voice production
  • Olfaction
  • Innate immunity
• Respiration - allows oxygen from air to enter the blood and carbon dioxide to leave the blood and enter the air.
• Respiration includes the following:

  • Ventilation or breathing
  • External respiration
  • Transport of respiratory gases
  • Internal respiration
• Ventilation or breathing - the movement of air into and out of the lungs.
• External respiration- exchange of oxygen and carbon dioxide between the air in the lungs (alveoli) and the blood.
• Transport of respiratory gases - oxygen and carbon dioxide must be transported to and from the lungs and tissue cells of the body. This uses blood as the transporting fluid.
• Internal respiration- the exchange of oxygen and carbon dioxide between the blood and the tissues.
• Structural Anatomy of the Respiratory System:

  • Upper Respiratory Tract (Upper Airway)
  • Lower Respiratory Tract (Lower Airway)
• Functional Anatomy of the Respiratory System:

  • Conducting Zone (Dead Space)
  • Respiratory Zones
• Upper Respiratory Tract (Upper Airway) - primarily refers to the parts of the respiratory system lying outside of the thorax or above the sternal angle.
• Upper Respiratory Tract (Upper Airway) - is the airway above the glottis or vocal cords.
• Upper Respiratory Tract (Upper Airway) - Includes the Nose, Pharynx, and Larynx.
• Lower Respiratory Tract (Lower Airway) - refers to the portions of the respiratory system from the trachea to the lungs.
• Conducting Zones (Dead Space) - These are the respiratory passages extending from the nose to the terminal bronchioles.
• Nose - consists of the external nose and nasal cavity.
• External nose - is the visible structure that forms a prominent feature of the face; composed of hyaline cartilage.
• Nares or nostrils - the external openings of the nose.
• Choanae - the openings into the pharynx.
• Nasal cavity - also called internal cavity.
• Nasal cavity - extends from the nares to the choanae; lies posterior to the external nose.
• Nasal septum - a partition dividing the nasal cavity into right and left parts.
• The nasal cavity is formed by the following structures:

  • Roof
  • Laterally
  • Medially
• Roof - ethmoid bone, sphenoid bone, frontal bone.
• Laterally - conchae or turbinates (superior, middle, and inferior) that protrude medially forming grooves inferior to each concha called meatus.
• The conchae increase the surface area of the nasal cavity and cause air to churn, so that it can be cleansed, humidified and warmed.
• Medially - the nasal septum.
• Paranasal Sinuses - are air-conducting spaces communicating with the nasal cavity and lined with a mucous membrane.
• What is the primary function of paranasal sinuses?

  To lighten the bones of the skull.
• What is the secondary function of paranasal sinus?

  To provide mucus for the nasal cavity and acts a resonant chambers for the production of sound.
• The paired sinuses include the:

  • Maxillary - largest of the paranasal sinuses
  • Frontal
  • Ethmoid
  • Sphenoid
• Pharynx - commonly known as throat.
• Pharynx - serves as the common passageway for food and air; extends from the base of the skull to the level of C6.
• Pharynx is divided into three:

  • Nasopharynx
  • Oropharynx
  • Laryngopharynx
• Nasopharynx - superior part of the pharynx.
• Nasopharynx - located posterior to the choanae and superior to the soft palate.
• Soft palate - an incomplete muscle and connective tissue partition separating the nasopharynx from the oropharynx.
• Uvula - the posterior extension of the soft palate.
• The soft palate forms the floor of the nasopharynx.
• Nasopharynx - where the auditory or eustachean tube of the middle ear opens.