![]() The normal respiratory rate of a child decreases from birth to adolescence. The respiratory rate is controlled by the respiratory center located within the medulla oblongata in the brain, which responds primarily to changes in carbon dioxide, oxygen, and pH levels in the blood. Respiratory rate can be an important indicator of disease, as the rate may increase or decrease during an illness. The respiratory rate is the total number of breaths, or respiratory cycles, that occur each minute. The alveolus is responsible for gas exchange Respiratory Rate and Control of Ventilationīreathing usually occurs without thought, although at times you can consciously control it, such as when you swim under water, sing a song, or blow bubbles. Figure 5.2c Structures of the Respiratory Zone. See Figure 5.2c for an illustration of the structures of the respiratory zone. ![]() An alveolus is one of the many small, grape-like sacs that are attached to the alveolar ducts.Īn alveolar sac is a cluster of many individual alveoli that are responsible for gas exchange. Bronchioles lead to alveolar sacs in the respiratory zone where gas exchange occurs AlveoliĪn alveolar duct is a tube composed of smooth muscle and connective tissue, which opens into a cluster of alveoli. The respiratory zone begins where the terminal bronchioles join a respiratory bronchiole, the smallest type of bronchiole, which then leads to an alveolar duct, opening into a cluster of alveoli. See Figure 5.2b for an illustration of the respiratory zone. In contrast to the conducting zone, the respiratory zone includes structures that are directly involved in gas exchange. This muscular wall can change the size of the tubing to increase or decrease airflow through the tube. The muscular walls of the bronchioles do not contain cartilage like those of the bronchi. There are more than 1,000 terminal bronchioles in each lung. Bronchioles, which are about 1 mm in diameter, further branch until they become the tiny terminal bronchioles, which lead to the structures of gas exchange. ![]() In addition, the mucous membrane traps debris and pathogens.Ī bronchiole branches from the tertiary bronchi. The main function of the bronchi, like other conducting zone structures, is to provide a passageway for air to move into and out of each lung. A bronchial tree (or respiratory tree) is the collective term used for these multiple-branched bronchi. The trachea branches into the right and left primary bronchi at the carina. Capillaries located just beneath the nasal epithelium warm the air by convection. This moist epithelium functions to warm and humidify incoming air. Interestingly, cold air slows the movement of the cilia, resulting in the accumulation of mucus that may, in turn, lead to a runny nose during cold weather. The cilia of the respiratory epithelium help remove the mucus and debris from the nasal cavity with a constant beating motion, thus sweeping materials toward the throat to be swallowed. The epithelium of the nasal passages, for example, is essential to sensing odors, and the bronchial epithelium that lines the lungs can metabolize some airborne carcinogens. Several structures within the conducting zone perform other functions as well. The major functions of the conducting zone are to provide a route for incoming and outgoing air, remove debris and pathogens from the incoming air, and warm and humidify the incoming air. The gas exchange occurs in the respiratory zone. ![]() The conducting zone of the respiratory system includes the organs and structures not directly involved in gas exchange. See Figure 5.2b illustrating major respiratory structuresįigure 5.2b Major Respiratory Structures: The major respiratory structures span the nasal cavity to the diaphragmįunctionally, the respiratory system can be divided into a conducting zone and a respiratory zone. Portions of the respiratory system are also used for non-vital functions, such as sensing odors, speech production, and for straining, such as during childbirth or coughing. The major organs of the respiratory system function primarily to provide oxygen to body tissues for cellular respiration, remove the waste product carbon dioxide, and help maintain acid-base balance. See Figure 5.2a Figure 5.2a Example of Gas Exchange Concept Map It is through this mechanism that blood is oxygenated and carbon dioxide, the waste product of cellular respiration, is removed from the body. At the respiratory membrane where the alveolar and capillary walls meet, gases move across the membranes, with oxygen entering the bloodstream and carbon dioxide exiting. Pulmonary ventilation provides air to the alveoli for this gas exchange process. The purpose of the respiratory system is to perform gas exchange. Open Resources for Nursing (Open RN) Concepts Related to Respiratory Medications Overview of the Respiratory System
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