ORIENTATION OF CEREBRAL VASCULAR SMOOTH-MUSCLE, MATHEMATICALLY MODELED

A helical and circular arrangement of smooth muscle in the wall of cerebral arteries was modelled mathematically, using biological data from other studies. The orientation of the long thin cellular nuclei was used as an indicator of cellular orientation in the wall of blood vessels. Models were produced of histological sections, in which muscle nuclei were outlined, alterning the principal parameters of angle of helical pitch and of angle of sectioning. The pattern in model sections was similar to the pattern of nuclei in an oblique section of the middle cerebral artery in which the nuclei had been measured microscopically. It was shown that the complex image of nuclei in an obliquely cut section could be used to decide between helically and circularly organised fibres, between single and multiple helical arrangements, and to permit an estimate of angle of helical pitch.