正常人及胎儿头发的扫描电镜观察

SEM OBSERVATION OF SCALP HAIR FROM NORMAL CHINESE ADULTS AND FETUSES

应用扫描电镜对16例不同年龄正常人及胎儿的头发进行了观察。发现毛干均为圆柱形,直径随年龄而变化,表面有毛小皮呈复瓦状。胎儿的毛干细,单个毛小皮即可包绕周径。毛小皮大致平行排列,间距较宽,游离缘平滑。5岁儿童头发直径增粗,毛小皮大小不一,多个毛小皮包绕周径,游离缘呈锯齿状,有细小的微突,并有较大的起伏弯曲,形成复杂纹理。青年人头发进一步增粗,毛小皮较宽大,排列较密,游离缘呈锯齿状,微突多而发达,表面可见小块碎片附着。中年人头发直径最粗,毛小皮排列最密,游离缘微突较少,从游离缘向下有垂直裂纹,表面有碎片及小孔。白发有时可见毛小皮整块脱落。老年人头发直径变细,毛小皮较窄小,排列较疏,呈鳞片状,游离缘平滑,少或无微突。白发有较大而深的孔洞。本文认为,毛发直径的粗细、毛小皮的大小、排列的疏密、游离缘的形态特点,微突的多少、表面有无小块碎片附着以及孔洞出现等,均可作为判断年龄的参考。

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.