upper tract

• air is drawn into the nasal cavity
• nasal cavity is a chamber lined with mucous membranes and tiny hairs called cilia
• in the nasal cavity, air is filtered, heated, and moistened to prepare it for its journey to the lungs
• nasal septum is a vertical partition of cartilage that divides the nasal cavity into two sides
• olfactory neurons are the receptors for the sense of smell, located in the nasal cavity
• olfactory neurons are found among the epithelial cells lining the nasal tract, and are covered with a layer of mucus
• the receptors are located higher in the nasal passage than air normally inhaled during breathing, thus, a person must sniff or inhale deeply to identify weak odors
• air passes from the nasal cavity to a muscular tube called the pharynx or throat
• pharynx serves as a passageway for food and air
• pharynx consists of three sections:

  • nasopharynx
  • oropharynx
  • laryngopharynx
• nasopharynx is posterior to the nose
• oropharynx is posterior to the mouth
• laryngopharynx is superior to the larynx
• adenoids are also known as pharyngeal tonsils
• adenoids are the collection of lymphatic tissue within the nasopharynx
• palatine tonsils are located in the oropharynx
• palatine tonsils are more commonly known as tonsils
• tonsils protect the opening to the respiratory tract from microscopic organisms that may attempt entry by this route
• larynx are also called voice box
• larynx contains the structures that make vocal sounds possible
• epiglottis is a leaf-shaped structure on top of the larynx
• epiglottis seals off the air passage to the lungs during swallowing
• the function of epiglottis ensures that food or liquids do not obstruct the flow of air to the lungs
• larynx is a short passage that joins the pharynx with the trachea