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Title: Impaired Air Conditioning within the Nasal Cavity in Flat-Faced Homo.
Authors: Nishimura, Takeshi  kyouindb  KAKEN_id  orcid https://orcid.org/0000-0003-3800-2194 (unconfirmed)
Mori, Futoshi
Hanida, Sho
Kumahata, Kiyoshi
Ishikawa, Shigeru
Samarat, Kaouthar
Miyabe-Nishiwaki, Takako  kyouindb  KAKEN_id
Hayashi, Misato  kyouindb  KAKEN_id
Tomonaga, Masaki  kyouindb  KAKEN_id  orcid https://orcid.org/0000-0002-9319-6991 (unconfirmed)
Suzuki, Juri  kyouindb  KAKEN_id
Matsuzawa, Tetsuro  kyouindb  KAKEN_id
Matsuzawa, Teruo
Author's alias: 西村, 剛
森, 太志
埴田, 翔
鈴木, 樹理
松沢, 哲郎
松澤, 照男
Issue Date: 24-Mar-2016
Publisher: Public Library of Science
Journal title: PLOS computational biology
Volume: 12
Issue: 3
Thesis number: e1004807
Abstract: We are flat-faced hominins with an external nose that protrudes from the face. This feature was derived in the genus Homo, along with facial flattening and reorientation to form a high nasal cavity. The nasal passage conditions the inhaled air in terms of temperature and humidity to match the conditions required in the lung, and its anatomical variation is believed to be evolutionarily sensitive to the ambient atmospheric conditions of a given habitat. In this study, we used computational fluid dynamics (CFD) with three-dimensional topology models of the nasal passage under the same simulation conditions, to investigate air-conditioning performance in humans, chimpanzees, and macaques. The CFD simulation showed a horizontal straight flow of inhaled air in chimpanzees and macaques, contrasting with the upward and curved flow in humans. The inhaled air is conditioned poorly in humans compared with nonhuman primates. Virtual modifications to the human external nose topology, in which the nasal vestibule and valve are modified to resemble those of chimpanzees, change the airflow to be horizontal, but have little influence on the air-conditioning performance in humans. These findings suggest that morphological variation of the nasal passage topology was only weakly sensitive to the ambient atmosphere conditions; rather, the high nasal cavity in humans was formed simply by evolutionary facial reorganization in the divergence of Homo from the other hominin lineages, impairing the air-conditioning performance. Even though the inhaled air is not adjusted well within the nasal cavity in humans, it can be fully conditioned subsequently in the pharyngeal cavity, which is lengthened in the flat-faced Homo. Thus, the air-conditioning faculty in the nasal passages was probably impaired in early Homo members, although they have survived successfully under the fluctuating climate of the Plio-Pleistocene, and then they moved "Out of Africa" to explore the more severe climates of Eurasia.
Description: ヒトの鼻腔機能はチンパンジーに及ばない -それでも、原人は出アフリカを遂げた-. 京都大学プレスリリース. 2016-03-25.
Rights: © 2016 Nishimura et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
URI: http://hdl.handle.net/2433/209816
DOI(Published Version): 10.1371/journal.pcbi.1004807
PubMed ID: 27010321
Related Link: http://www.kyoto-u.ac.jp/ja/research/research_results/2015/160325_1.html
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