A single red blood corpuscle fills the lumen.
Arrowheads point to thickened basement membranes.
Distinct A and I bands. Composed of protein polysaccharicles. Thickening of the capillary basement membrane has been described in this and other muscle disorders, in diabetes mellitus, and in some kidney diseases. Fills the lumen of a capillary and is a useful, but rough, internal measure. In man, the red blood corpuscle is approximately 6.0 gm in diameter in tissue sections.