Final answer:
The statement is true; alopecia totalis refers to the complete loss of scalp hair, and the loss of all body hair is called alopecia universalis. Hair serves important functions for homeostasis, including insulation and protection, with its loss potentially impacting thermal regulation. Hair growth occurs in three main stages and hair loss can disrupt the natural hair renewal cycle.
Step-by-step explanation:
The statement that the complete loss of all body hair is known as alopecia totalis is true. Alopecia totalis is a condition involving the loss of all scalp hair, but when one loses all body hair, it is referred to as alopecia universalis. Hair plays several important roles in the body, contributing to the integumentary system. The loss of hair can disturb homeostasis by affecting thermal regulation, as hair helps to retain heat by creating an insulating layer of air around the body. It also serves as a protective barrier, shielding the skin from sun rays and other environmental hazards. Hair can even have a role in communication; for instance, the hair on our eyebrows can convey expressions.
Humans lost most of their body hair about a million years ago, possibly as an adaptation to life in hot savanna climates, aiding in cooling through evaporation of sweat. The Smithsonian Magazine explores hypotheses on this change being a way to control parasites or as an aid for thermoregulation. Humans lived without clothes for approximately 830,000 years after losing most of their body hair, before they started wearing clothes, which then led to evolutionary changes in body lice.
Hair growth occurs in three stages: the anagen phase of active growth, the catagen transitional phase, and the telogen resting phase, after which hair is eventually shed and replaced.