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Deposition of Aerosol Particles in Human Respiratory System
Published in Katarzyna Majchrzycka, Nanoaerosols, Air Filtering and Respiratory Protection, 2020
During the increased physical activity, because of the demanded rate of pulmonary ventilation, breathing through the mouth is predominating. In the case of dosing medicine by inhalant methods (aerosol therapy), the inhale of the airflow containing the medicinal particles is also done predominantly through the mouth. Oral and nasal cavities connect to create a pharyngeal cavity, which then transitions into larynx and esophagus. The larynx acts as a valve. Its cartilaginous piece, called an epiglottis, closes the inlet to the larynx and prevents the food from getting there or, while opening the larynx, it presses at the entry to the esophagus and prevents the air from getting there. Behind the larynx, where vocal folds are located, the LA begin.
Basic Chemical Hazards to Human Health and Safety — I
Published in Jack Daugherty, Assessment of Chemical Exposures, 2020
Eight sinuses, four on each side of the nose, help equalize air pressure in the nasal cavity, and, because they are linked with the nasal passage, are easily irritated. The pharynx and larynx are also easily irritated by either inhaled or ingested irritants. On either side of the pharynx, behind the mouth, tonsil tissue can be susceptible to irritants. The pharynx serves as a passageway for air, but also for food and other ingested materials. At the lower end of the pharynx is the glottis, a narrow slit covering the opening into the larynx. Covering the glottis is the epiglottis a small flap that prevents swallowed materials from entering the larynx. This is where the pharynx separates into the larynx and esophagus. Next, on the respiratory side, are the trachea and bronchi, then the bronchioles and alveoli are attacked by irritants in the worst exposures.
Designing for Head and Neck Anatomy
Published in Karen L. LaBat, Karen S. Ryan, Human Body, 2019
The pharynx, the space lying behind the nasal and oral cavities, and behind the larynx in the neck, extends between the trachea and the vertebral bodies to the level of the cricoid cartilage. The pharynx works with the epiglottis to move food into the digestive tract or air into the larynx. Food travels from the mouth through the oropharynx to the laryngopharynx, the section of the pharynx behind the voice box, then into the esophagus to the stomach. The flexible esophagus, a flat fibromuscular tube, links the mouth and the stomach. It expands to accommodate a mouthful of food after you swallow. The smooth muscles in the wall of the esophagus contract sequentially to squeeze the food through the esophagus to the stomach.
Potential effects of lingual fats on airway flow dynamics and particle deposition
Published in Aerosol Science and Technology, 2020
Bingjie Ma, Agisilaos Kourmatzis, Yongling Zhao, Runyu Yang, Hak-Kim Chan, Fatemeh Salehi, Shaokoon Cheng
The epiglottis, forming part of the upper airway, is a piece of elastic cartilage that has a leaf-like structure which projects obliquely cranially behind the tongue. This part of the airway can interfere with breathing, and studies using magnetic resonance imaging (MRI) have demonstrated that in some healthy human subjects, the tongue contracts to increase the upper airway space at the level of the epiglottis to improve or enable flow (Cheng, Brown, et al. 2014). Given the unique geometry of the epiglottis and that the pharynx tends to be the narrowest at this section of the upper airway, flow at the epiglottis is complex, but the implications of this on particle deposition remain poorly understood.
Computational modeling of child’s swallowing to simulate choking on toys
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2020
Yukihiro Michiwaki, Takahiro Kikuchi, Tetsu Kamiya, Yoshio Toyama, Motoki Inoue, Keigo Hanyuu, Megumi Takai, Seiichi Koshizuka
At the start of swallowing, the soft palate lifted upward. On the other hand, the tongue started a progressively wave-like movement as its concaved section gradually progressed backward, while the toy ball was transported to the pharynx. The epiglottis rotated downward to cover the larynx and preserve the airway (Figure 4(d)). The ball entered even deeper in the pharynx to rest on the rotated epiglottis. The toy ball of 15 mm in diameter not only occupied the airway in the pharynx but also made the epiglottis cover the larynx, causing total airway obstruction (Figure 4(e)). The airway obstruction induces choking or asphyxia, which causes death or severe damage due to hypoxia.
Video laryngeal masks in airway management
Published in Expert Review of Medical Devices, 2022
Manuel Á. Gómez-Ríos, Teresa López, José Alfonso Sastre, Tomasz Gaszyński, André A. J. Van Zundert
Although SADs are easy devices to use, troubleshooting can be indicated and requires a flexible and skillful anaesthetist to solve issues related to insertion and maintenance: a) inadequate anasthesia may result in insufficient depth of anesthesia with breath holding, straining, laryngospasm, bronchospasm and airway obstruction; b) the tip of the epiglottis can be downfolded, resulting in air leakage or airway obstruction; c) inappropriate sizing of the device may result in difficulties obtaining an adequate seal; d) patients anatomy can make insertion problematic; e) the distal tip of the cuff can be downfolded backwards or sit across the vocal cords [25–27].