The Integument SystemThe Integument System
Refers to the covering of the body and is the body’s first line of Refers to the covering of the body and is the body’s first line of
defense, acting as a barrier against disease and physical hazards. defense, acting as a barrier against disease and physical hazards.
Helps control body temperature by releasing heat through sweat or Helps control body temperature by releasing heat through sweat or
by constricting blood vessels to act as insulation. by constricting blood vessels to act as insulation.
It includes the skin, hair, and nails. It includes the skin, hair, and nails. HairHair is made of keratinized cells. is made of keratinized cells.
Finger nails Finger nails and toenails are also composed of keratin. and toenails are also composed of keratin.
The mammary The mammary glands, or breasts, are also considered part of the glands, or breasts, are also considered part of the
integumentary system.integumentary system.
The skin is composed of the The skin is composed of the epidermis and dermisepidermis and dermis. The epidermis . The epidermis
has no blood or nerves and is constantly discarding dead cells. The has no blood or nerves and is constantly discarding dead cells. The
dermis, which is made of living cells, contains capillaries, nerves, dermis, which is made of living cells, contains capillaries, nerves,
and lymphatics. The dermis also contains the sebaceous glands, and lymphatics. The dermis also contains the sebaceous glands,
sweat glands, and hair.sweat glands, and hair.
The subcutaneous layer The subcutaneous layer of tissue is beneath the dermis but is of tissue is beneath the dermis but is
closely interconnected to it. It separates the skin from the other closely interconnected to it. It separates the skin from the other
organs (for example, the muscular system, as in the illustration).organs (for example, the muscular system, as in the illustration).