The fluid dynamics of canine olfaction: unique nasal airflow patterns as an explanation of macrosmia
The fluid dynamics of canine olfaction: unique nasal airflow patterns as an explanation of macrosmia
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DOI：
10.1098/rsif.2009.0490
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发表时间：
2010-06-06
影响因子：
3.9
通讯作者：
Settles, Gary S.
中科院分区：
文献类型：
--
作者：
Craven, Brent A.;Paterson, Eric G.;Settles, Gary S.
犬科动物的鼻腔含有数亿个感觉神经元，位于嗅觉上皮细胞中，嗅觉上皮细胞排列在鼻子后部凹进的曲折的鼻甲骨中。对犬嗅觉敏锐度的传统解释，包括较大的感觉器官大小和受体基因库，忽视了嗅觉过程中气味传输的流体动力学。但将气味输送到鼻子的感觉部分是嗅觉的第一个关键步骤。在这里，我们报告了关于犬嗅探的新实验数据，并展示了嗅探频率、吸气气流速率和潮气量与体重的异速缩放。接下来，根据高分辨率磁共振成像扫描重建的犬鼻腔解剖学精确三维模型中的气流的计算流体动力学模拟表明，在嗅探过程中，每个鼻孔获取空间上独立的气味样本，可用于双边刺激强度比较和气味源定位。计算表明，在鼻子内部，嗅探过程中会形成独特的鼻气流模式，该模式针对将气味输送到鼻子嗅觉部分进行了优化。这些结果与人类鼻腔气流形成鲜明对比。我们认为，哺乳动物的嗅觉功能和敏锐度可能在很大程度上取决于鼻腔气流模式的气味输送，这是由于高度发达的嗅觉隐窝（在犬科动物等大型动物中）的存在或缺乏（在包括人类在内的微观动物中）造成的。
The canine nasal cavity contains hundreds of millions of sensory neurons, located in the olfactory epithelium that lines convoluted nasal turbinates recessed in the rear of the nose. Traditional explanations for canine olfactory acuity, which include large sensory organ size and receptor gene repertoire, overlook the fluid dynamics of odorant transport during sniffing. But odorant transport to the sensory part of the nose is the first critical step in olfaction. Here we report new experimental data on canine sniffing and demonstrate allometric scaling of sniff frequency, inspiratory airflow rate and tidal volume with body mass. Next, a computational fluid dynamics simulation of airflow in an anatomically accurate three-dimensional model of the canine nasal cavity, reconstructed from high-resolution magnetic resonance imaging scans, reveals that, during sniffing, spatially separate odour samples are acquired by each nostril that may be used for bilateral stimulus intensity comparison and odour source localization. Inside the nose, the computation shows that a unique nasal airflow pattern develops during sniffing, which is optimized for odorant transport to the olfactory part of the nose. These results contrast sharply with nasal airflow in the human. We propose that mammalian olfactory function and acuity may largely depend on odorant transport by nasal airflow patterns resulting from either the presence of a highly developed olfactory recess ( in macrosmats such as the canine) or the lack of one ( in microsmats including humans).