SEM OBSERVATION OF SCALP HAIR FROM NORMAL CHINESE ADULTS AND FETUSES / 解剖学报

ABSTRACT

Hair from 16 scalps of different ages (from 5 months to 77 years old) have been observed with SEM. The surface ultrastructure of the cuticle of the hair shaft is distinctly seen. The cuticles are arranged like shingles. Their free margins direct toward the end of the hair. The appearance and diameter of the shaft vary from age to age. The hair shaft of fetus is very fine. The cuticles are so broad that a single cuticle may encircle the shaft. They are parallel to each other. The intervals between successive free margins of cuticles are wide. Their free margin is smooth. The hair shaft of a 5-year old child is coarse. The cuticles vary in size. It requires a number of cuticles to encircle the shaft. The free margin becomes jagged and curved with microprotrusions on it. The intervals between free margins of the cuticles vary in width. The hair shaft of the youths is coarser. The cuticles are broad and arranged regularly. The intervals between free margins of the cuticles are comparatively narrow. There are numerous well developed microprotrusions on the free margin. The hair shaft of the middle aged is the coarsest and the intervals between free margins of the cuticles are the narrowest of all. There are less microprotrusions than those of the youths'. They are getting less and less, so that the free margin is partly smooth. Many cracks perpendicular to the free margin appear apparently and much debris fallen from the cuticle is attached to the surface of the the shaft. Sometimes falling of a whole cuticle may be observed. The hair shaft of the aged people is finer than that of the youths'. The intervals between cuticles with loose squamous arrangement are wider than those seen in the young and middle aged people. The free margin is usually smooth with only a few microprotrusions if any. Sometimes big and deep holes may be found on the surface of white hair. It is considered that the diameter of hair shaft, the size and arrangement of cuticles, the characteristic structures of free margin, the number of microprotrusions and with or without small debris attached to or holes appeared on the shaft are all related to age.