Final answer:
The two major types of hair in the integumentary system are vellus and terminal. The integumentary system's functions include protection, regulation of homeostasis, and sensory interaction, with hair playing a role in sensation, filtration, and thermoregulation.
Step-by-step explanation:
The two major types of hair in the integumentary system are vellus and terminal hair. Vellus hair is fine, light, and short, often referred to as "peach fuzz", that develops in most areas of the body from childhood. Terminal hair is thick, long, and pigmented, which usually grows on the scalp, face, armpits, and pubic area after puberty due to hormonal changes.
The integumentary system includes the skin, hair, and nails, which have several functions including protection, regulation of homeostasis, and sensory interaction. The skin itself consists of two primary layers: the epidermis and the dermis. The epidermis is the outermost layer, providing a barrier against pathogens, UV light, and water loss, and also involved in vitamin D synthesis. The thicker dermis lies below and contains hair follicles from which hair grows.
Hair serves various homeostatic functions, such as head hair preventing heat loss and protecting the skin from UV radiation, nasal hairs filtering inhaled particles, and overall body hair contributing to sensory input when touched or moved.