Intrinsic Curvature in Wool Fibres Is Determined by the Relative Length of Orthocortical and Paracortical Cells

The study investigated the cause of hair curvature in merino wool fibres using confocal microscopy to measure orthocortical and paracortical cells. It found that curvature was not due to a higher number of cells on the convex side but rather the longer length of orthocortical cells compared to paracortical cells. The study contradicted the theory that curvature correlates with the proportions of these cell types, suggesting instead that the difference in cell length is crucial. These findings have implications for understanding hair curvature in other types of hair, including human scalp hair.