Vellus refers to the type of short, soft, and fine hair that covers the human body, particularly the arms, legs, chest, and face, excluding the palms, soles, and the area around the genitals. This type of hair is typically unpigmented or lightly pigmented and differs from the longer, coarser, and darker terminal hair found on the scalp, eyebrows, and other body parts. Vellus hair is commonly associated with children, as it becomes more prevalent in infancy and gradually changes during puberty as hormonal levels fluctuate.
This type of hair serves several functions, including providing some insulation and aiding in the evaporation of sweat. Additionally, it can contribute to the perception of touch or sensation on the skin's surface. Vellus hair is generally less visible compared to terminal hair and often requires close inspection to be noticed. In some medical conditions such as hypertrichosis or hirsutism, an excessive amount of vellus hair may grow in areas typically associated with terminal hair, leading to abnormal hair growth patterns.
Overall, vellus hair serves as a peculiar characteristic of the human body and plays a role in various physiological and developmental processes. Its texture, density, and distribution can vary among individuals and are influenced by genetic factors, hormonal changes, and age.
