Page 39 - 84 human physiolofy part-1

The Integumentary System

Hair

Types of hair

Humans have three different types of hair:

• Lanugo, the fine hair that covers nearly the entire body of embryos
• Vellus hair, the short, fine, "peach fuzz" body hair that grows in most places on the human
body in both sexes
• Terminal hair, the fully developed hair, which is generally longer, coarser, thicker, and
darker than vellus hair

Pathological impacts on hair

Drugs used in cancer chemotherapy frequently cause a temporary loss of hair, noticeable on the
head and eyebrows, because they kill all rapidly dividing cells, not just the cancerous ones. Other
diseases and traumas can cause temporary or permanent loss of hair, either generally or in patches.

The hair shafts may also store certain poisons for years, even decades, after death. In the case of
Col. Lafayette Baker, who died July 3, 1868, use of an atomic absorption spectrophotometer showed
the man was killed by white arsenic. The prime suspect was Wallace Pollock, Baker's brother-in-law.
According to Dr. Ray A. Neff, Pollack had laced Baker's beer with it over a period of months, and a
century or so later minute traces of arsenic showed up in the dead man's hair. Mrs. Baker's diary seems
to confirm that it was indeed arsenic, as she writes of how she found some vials of it inside her
brother's suit coat one day.

Wikibooks | 39