Vellus hair

from Wikipedia, the free encyclopedia
Comparison of vellus hair (left) and terminal hair ( right) in humans. The absence of subcutaneous tissue in vellus hair is visible .
Vellus hair on a woman's navel

The vellus hair , also called intermediate hair , is the marrowless downy hair with a maximum thickness of 0.04 mm and a maximum length of 1 cm that occurs in humans for the first time in childhood. It replaces lanugo hair from the age of 6 months . It has very little pigmentation , so most people are colorless to light blond. Vellus hair grows on the entire surface of the body with the exception of the groin skin on the palms of the hands and feet as well as the lips and nipples. In the course of later development, the vellus hair partially forms the terminal hair , which is more heavily pigmented , thicker and contains medullary. During puberty , around 45 percent of women and around 90 percent of men’s vellus hair are converted into terminal hair. The conversion is caused by androgens . This process begins in the axillary and genital areas and, depending on predisposition, extends to the chest, abdomen, back, extremities and face in adult men .

Terminal hair can also be converted back into vellus hair on the head (retrograde metamorphosis). Then receding hairline and baldness develop ( androgenetic alopecia ).

literature

Web links

Individual evidence

  1. G. Kautz, K. Rick, M. Sandhofer: Photoepilation: To the practice of hair removal with light and laser systems . Springer, Berlin 2013, ISBN 978-3-7985-1951-0 , pp. 8 .
  2. T. Nasemann, W. Sauerbrey: Textbook of skin diseases and venereal infections for students and doctors. Springer Verlag, 2013, p. 298 ( online ).
  3. G. Kautz, K. Rick, M. Sandhofer: Photoepilation: To the practice of hair removal with light and laser systems. Springer, 2013, p. 8 ( online ).