Nov. 14, 2011 -- Mini strokes, with symptoms that last just a few minutes or hours, are well-recognized warning signs for potentially deadly larger strokes. Now new research confirms that they are associated with a lower life expectancy.
A cross section is the shape we get when cutting straight through an object. The cross section of this object is a triangle. It is like a view into the inside of something made by cutting through it.
When cut in longitudinal section, smooth muscle nuclei appear very long and sometimes wiggly (due to contraction). In cross-sectioned smooth muscle, only a fraction of the fibers display nuclei. Recall that each smooth muscle fiber is a single cell, each with its own nucleus. In each such cell, the nucleus occupies only a small proportion of the cell's total length. So nuclei appear only in a similarly small proportion of the fibers cut by any single section. A very small bundle of smooth muscle can be particularly inconspicuous when cut in cross section.