Basic data regarding the hairs of the Koreans and other Asians are rare, while basic data on the physiology of the Caucasian hair abound.
To identify the Physical and morphological features of the hairs of Koreans of different ages and genders, the...
Basic data regarding the hairs of the Koreans and other Asians are rare, while basic data on the physiology of the Caucasian hair abound.
To identify the Physical and morphological features of the hairs of Koreans of different ages and genders, these authors divided the 60 study subjects (30 males, 30 females) into five age groups of six subjects each by gender, measured the thickness, water swelling, alkali solubility, and tensile strength of their hairs and the intervals and thicknesses of their cuticles, and observed their cuticles and cortex under an electron microscope. The results of the study showed that the thickness of the hairs of both the male and female subjects increased significantly in proportion to their ages from childhood to adulthood (p<0.05) but became thin in old age due to senility. The male hairs were relatively thicker than the female hairs, except in the elderly subjects. The water swelling increased in childhood in both the male and female subjects, decreased in adolescent and adulthood, and increased again in old age. The water swelling by gender showed similar patterns to the hair thickness. The alkali solubility of the hairs, unlike the water swelling, was higher in the adolescent and elderly subjects than in the infant subjects, and it increased from adolescent to old age. The alkali solubility of the male hairs was higher than that of the female hairs, and a good correlation (r = -0.719) was found between hair thickness and alkali solubility. The tensile strength of both the male and female hairs gradually increased in childhood and adolescent, when the body metabolism is active, but decreased in old age with the onset of senility. A significantly good correlation (r = 0.803) between hair thickness and tensile strength was also shown.
Under a scanning electron microscope, it was observed that the intervals of the cuticle gradually increased from childhood through adolescent and in adulthood and old age. The intervals of the male hair cuticle were wider than those of the female hair cuticle. The thickness of the hair cuticle increased in childhood through adolescent but gradually decreased in adulthood and old age. There was no big difference in the morphology of the cuticle between the male and the female subjects, and the overlapping tail ends of the cuticle layers became regular and gentle with aging, while the intervals between the cuticles became wider.
Under a transmission electron microscope, it was observed that the boundary between the cuticle layers and the cortex in the infant subjects was not obvious, that the melanin granules in the cortex of both the male and the female subjects formed hard lumps, that the granules were broken down at the cuticle layers after they were pushed up from the cortex to the cuticle layers or at the EndC and ExoC layers, and that vacuoles were formed where the melanin granules had been. In the elderly, many melanic pigments, which are abundant in the cuticles, were dispersed evenly in EndC and in ExoC, and the melanin granules diffused in the hair cortex were pushed up to the EndC and ExoC layers in the cuticle layers. In addition, the boundary of the macrofibril bundles was not obvious.
In the infant, adolescent, and elderly groups of both the male and female subjects, the roughness of the hairs was observed to decrease as the cuticle intervals became wider. In the infant subjects, the roughness of the hairs was relatively high due to the narrow cuticle intervals and overlapping layers, while the roughness was low in the adolescent, adult, and elderly subjects due to their wide cuticle intervals and wavy scales.
In conclusion, it is suggested that the differences in the Physical and morphological features of the Korean hairs by gender and age identified in the present study can be highly useful as basic data for hair physiology.