{"id":1002,"date":"2011-08-26T14:14:21","date_gmt":"2011-08-26T04:14:21","guid":{"rendered":"http:\/\/blog.dbohs.com\/?p=1002"},"modified":"2024-10-11T15:46:54","modified_gmt":"2024-10-11T05:46:54","slug":"the-shape-of-a-nose","status":"publish","type":"post","link":"https:\/\/blog.dbohs.com\/?p=1002","title":{"rendered":"The Shape of a Nose"},"content":{"rendered":"

The Scientific American<\/strong>\u00a0September\u00a02001 has an\u00a0article by Joan Raymond\u00a0The Shape of a Nose<\/a>\u00a0<\/strong>\u00a0that has implications for inhalation toxicology. [The original\u00a0article\u00a0is
\nNoback, M. L., K. Harvati, et al. (2011). “Climate-related variation of the human nasal cavity.” American Journal of Physical Anthropology 145(4): 599-614]<\/p>\n

“Scientists have long been interested in the relation between a nose\u2019s form and its function. New research is showing that climate may have played an important role in how the nose\u2019s internal structure evolved.<\/em><\/p>\n

Researchers in Germany recently showed that individuals from cold, dry climates, such as Greenland or Siberia, had higher and narrower nasal cavities than those from hot, humid climates, such as Papua New Guinea or Gabon. The German team, led by Marlijn Noback of Eberhard Karls University of T\u00fcbingen, took computer-aided measurements of the nasal cavities of 100 skulls representing 10 human groups living in five different climates. They found that the nasal cavities of cold, dry climate populations are relatively high and show a larger and more abrupt change in diameter in the upper part of the cavity than those of hot, humid climate populations.<\/strong> Her research was published online in the\u00a0American Journal of Physical\u00a0Anthropology<\/a>\u00a0this past June.<\/em><\/p>\n

This narrowing of the nasal passage enhances contact between the air and the mucosal tissue, which helps to warm and humidify that air, Noback notes. Cold, dry climate populations also show a relatively longer nasal cavity, giving this population more space in which to bring incoming air in line with body temperature. Microscopic hairs called cilia, which line the nasal passage, help to keep out pathogens and dust that may infect or irritate the lungs, and the cilia work more efficiently when incoming air is moist. \u201cProper heating and humidification of air in colder climates are important for respiratory health,\u201d says paleoanthropologist Nathan Holton of the University of Iowa.\u00a0 In warm-climate-adapted populations, inhalations are not directed toward the narrow upper part of the nasal cavity for warming. So \u201cpeople from warm climates, moving into cold climates, could be more susceptible [to] colds and related diseases,\u201d Noback says.\u00a0<\/em><\/p>\n

Which sort of nose do you have? Although you can\u2019t tell much about the external shape of the nose when looking at its internal structure<\/strong>, a narrow, longer internal cavity is generally linked to a relatively narrower and more projecting nose, Holton says”<\/em><\/p>\n

It is not clear from this excerpt what the implications are for Eskimos and other Asiatic people with flatter noses who live in cold climates. I must read the article.<\/p>\n

The\u00a0velocity\u00a0of air in the nose and the sharpness of\u00a0changes\u00a0in direction have great\u00a0effects\u00a0on particle deposition. If “nasal cavities of cold, dry climate populations are relatively high and show a larger and more abrupt change in diameter in the upper part of the cavity than those of hot, humid climate populations”, <\/strong><\/em>then for people with high nasal velocities and sharp changes \u00a0in the direction of air:<\/p>\n