Optimal lamellar arrangement in fish gills.
Fish respire through gills, which have evolved to extract aqueous oxygen. Fish gills consist of filaments with well-ordered lamellar structures, which play a role in maximizing oxygen diffusion. It is interesting that when we anatomically observe the gills of various fish species, gill interlamellar distances (d) vary little among them, despite large variations in body mass (Mb). Noting that the small channels formed by densely packed lamellae cause significant viscous resistance to water flow, we construct and test a model of oxygen transfer rate as a function of the lamellar dimensions and pumping pressure, which allows us to predict the optimal interlamellar distance that maximizes the oxygen transfer rate in the gill. Comparing our theory with biological data supports the hypothesis that fish gills have evolved to form the optimal interlamellar distances for maximizing oxygen transfer. This explains the weak scaling dependence of d on Mb: d ∼ Mb(1/6).
Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744, Korea; and.
Keunhwan
K
Park
Department of Mechanical Engineering, Sogang University, Seoul 121-742, Korea hyk@snu.ac.kr wonjungkim@sogang.ac.kr.
Wonjung
W
Kim
Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744, Korea; and hyk@snu.ac.kr wonjungkim@sogang.ac.kr.
Ho-Young
HY
Kim
D000818:Animals; D005075:Biological Evolution; D005880:Gills / Q000033:anatomy & histology* / Q000098:blood supply* / Q000502:physiology; D044085:Microfluidics; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism; D010473:Perciformes / Q000033:anatomy & histology* / Q000502:physiology; D012119:Respiration; D014867:Water / Q000378:metabolism
D014867:Water; D010100:Oxygen
biofluiddynamics; biomechanics; fish respiration