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Outdoor Air Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
A complex mixture of gases, PM, and chemicals present in outdoor and indoor air produces adverse health effects such as those seen in the chemically sensitive and chronic degenerative patients. Because the nasal cavity is a common portal of entry for such pollutants, the nasal olfactory and respiratory mucosa are vulnerable to damage and well-known targets for air pollutant-induced toxicity and carcinogenicity.304–307 The nose–brain barrier depends on intact epithelia, including tight junctions and an intact xenobiotic metabolizing capacity.308 Olfactory receptor cell dendrites are in direct contact with the environment, and, thus, pinocytosis and neuronal transport are likely routes of access to the CNS of potential toxins.309 Olfactory receptor neurons project from the sensory epithelium to targets within the olfactory bulb, the first synaptic relay in the olfactory pathway.309
Nasal and Pulmonary Drug Delivery Systems
Published in Ambikanandan Misra, Aliasgar Shahiwala, In-Vitro and In-Vivo Tools in Drug Delivery Research for Optimum Clinical Outcomes, 2018
Pranav Ponkshe, Ruchi Amit Thakkar, Tarul Mulay, Rohit Joshi, Ankit Javia, Jitendra Amrutiya, Mahavir Chougule
The nasal cavity (from the nose to thepharynx) is entirely lined with nasal mucosa and forms the physical barrier of the body’s immune system. It provides mechanical protection against pathogens and harmful substances. The human nasal cavity is divided by the septum into two symmetrical parts. Each of the parts made up of three regions: (a) the vestibule region (inside the nostrils, area of 0.6 cm2) (b); olfactory region, situated at top of the nasal mucosa (covers only 10% of the total nasal mucosal area of 150 cm2); and (c) respiratory region, made up of 3 nasal turbinates (superior, middle, and inferior) (Illum 2003; Illum 2012) (Figure 4.2).
Deposition of Aerosol Particles in Human Respiratory System
Published in Katarzyna Majchrzycka, Nanoaerosols, Air Filtering and Respiratory Protection, 2020
During inhalation, the air is introduced into the respiratory system through the nasal cavity or mouth (Figure 2.3). Nasal cavity geometry is complicated, and it serves three main purposes: warming the introduced air, humidifying it and preliminary cleaning it from the aerosol particles.
Micro- and nanoparticle transport and deposition in a realistic neonatal and infant nasal upper airway
Published in International Journal of Modelling and Simulation, 2023
John Valerian Corda, B Satish Shenoy, Kamarul Arifin Ahmad, Leslie Lewis, Prakashini K, Anoop Rao, Mohammad Zuber
The human nasal cavity acts as the first line of filtration of the inhaled dust and unwanted particles so that the inspired air enters the lungs in the purest form possible. In addition to the filtration, the nasal cavity also performs the thermal conditioning and humidification of the inspired air [30]. Nasal geometry is a complicated flow domain and in vivo measurements for flow and particle depositions are challenging due to which researchers have sought to use in silico methods using CFD to effectively determine the required flow parameters [31–35].
Voxel-based simulation of flow and temperature in the human nasal cavity
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Shinya Kimura, Shuta Miura, Toshihiro Sera, Hideo Yokota, Kenji Ono, Denis J. Doorly, Robert C. Schroter, Gaku Tanaka
The nasal airway plays various roles as part of the upper respiratory system, which extends from the nasal cavity to the trachea. Sensing odorant molecules and filtering pollutants and airborne particles across the nasal mucosa are the primary functions. The nasal cavity has an air-conditioning function to ensure the inspiratory air is at the proper temperature and humidity to protect the lower respiratory tract (Elad et al. 2008). Inspired air is heated and humidified by the mucosa layer with rich blood vessels as it travels from the nostrils to the nasopharynx (Keck et al. 2000; Lindemann et al. 2002). In addition, it was suggested that subjective perception of nasal obstruction may correlate better with mucosal cooling, rather than with nasal resistance (Sullivan et al. 2014). Therefore, it is important to clarify the heat transfer characteristics in the nasal cavity. Because the intricate anatomy of the nasal cavity makes it difficult to predict detailed airflow patterns in-vivo (Lang 1989), physical models of the nasal cavity derived from medical images have been used in both experimental (Hahn et al. 1993; Kelly et al. 2000; Chung et al. 2006; Chung and Kim 2008; Doorly et al. 2008) and computational (Keyhani et al. 1995; Zhao et al. 2006; Doorly et al. 2008; Taylor et al. 2010) studies to determine the detailed patterns of the nasal airflow. In particular, computational fluid dynamics (CFD) has enabled detailed airflow simulation throughout the nasal cavity based on CT scans of individual subjects (Croce et al. 2006; Ishikawa et al. 2006; Doorly et al. 2008; Gambaruto et al. 2009; Kumahata et al. 2010; Taylor et al. 2010; Na et al. 2012; Bates et al. 2015). To model a realistic nasal cavity shape with a computational grid in CFD, boundary-fitted grids are currently used. On one hand, this method is capable of accurately reconstructing the complex geometry using thin boundary layers allocated along the surface. On the other hand, this method requires high-quality grid generation, which affects calculation accuracy.