c. Respiratory portion i. Bronchioles (respiratory and terminal) ii. Alveolar ducts iii. Alveolar sacs iv. Alveoli The human respiratory system includes all structures that conduct air to and from the lungs. Air moves through the nasal cavity (Figure 2.3, Figure 2.4) , the pharynx (Figure 2.5) , the larynx (Figure 2.6) the trachea, and the bronchi to the lungs (Figure 2.7) . Along the way, air is filtered so that it is free of debris, warmed, and humidified. By the time the air reaches the lungs, it is at body temperature and is saturated with water. The nasal cavities or fossae, composed of bone and cartilage, are made up of several parts. The left and right fossae are separated by the nasal septum. The vestibule is the most external portion of the nasal cavity just inside the nostrils. The vestibule is lined with stratified squamous epithelium which is a continuation of the skin from the face. Short thick hairs called vibrissae are also found here and act as a screening device for the respiratory tract. Past the vestibule, multiple nasal conchae or folds are present in the nasal cavity increasing the surface area so that the incoming air can be warmed and humidified. To accomplish warming the air, the nasal cavity is highly vascularized (has a large amount of blood vessels). This is one reason why nosebleeds can commonly occur. NursingABC - Module 4 of 34 9/6/2019, 2:57 AM
Figure 2.3 Midsagittal view of upper respiratory structures Figure 2.4 The nasal cavities (left nasal cavity is highlighted in blue) are part of the conducting portion of the respiratory system NursingABC - Module 5 of 34 9/6/2019, 2:57 AM
Figure 2.5 The pharynx is made up of three portions: The nasopharynx, the oropharynx, and the laryngopharynx The pharynx is comprised of three regions (Figure 2.5) : the nasopharynx, oropharynx, and laryngopharynx. The nasopharynx is the connection area between the nasal cavity and the pharynx, generally above the soft palate. Eustachian tubes connect the nasopharynx to each middle ear. The oropharynx is the region posterior to the mouth and anterior to the epiglottis. The laryngopharynx is the area where the pharynx, larynx, and esophagus meet. It is superior and posterior to the larynx. Epithelium varies within the pharynx due to the amount of movement within the area. Stratified squamous epithelium protects these tissues from frictional damage. NursingABC - Module 6 of 34 9/6/2019, 2:57 AM
Figure 2.6 The larynx (in blue), anterior view Figure 2.7 Anterior view of larynx, trachea (cartilage on the anterior portion of trachea in blue), bronchi, bronchioles and lungs NursingABC - Module 7 of 34 9/6/2019, 2:57 AM
The hard palate (Figure 2.8) and the soft palate (Figure 2.9) separate the nasal cavities from the mouth.
- Summer '18
- Renee Correll