The integumentary system of the head and neck includes the skin and hair of the face, head and neck. The skin of the face is the part of the body which is most often exposed to sunlight, the elements, and environmental pollutants; thus, it is more prone to acne and to becoming dry or otherwise showing accumulated damage from these influences than the skin on the rest of the body.
The top and upper sides of the head are typically the single largest collection of hair on the human body. Facial hair includes the eyebrows and eyelashes; visible air also grows between the nose and upper lip and along the cheeks and lower edge of the jaw line and sometimes extends down the neck. This facial hair is typically very fine in women and somewhat thicker in men, although this can vary.
The integumentary system is made up of the skin and its appendages (such as the nails and the hair); its primary function is to protect the body from damage; it is also involved in temperature regulation and in the sense of touch. Upon exposure to sunlight, the integumentary system is also the primary vehicle for synthesis of vitamin D.