Which organ is NOT part of the integumentary system?

The integumentary system comprises the skin and its associated structures, including hair, nails, and glands such as sweat and sebaceous glands. The primary function of this system is to protect the body from external damage, regulate temperature, and facilitate sensory perception.

Bones, while crucial components of the skeletal system, are not included in the integumentary system. They serve different roles, predominantly providing structure, support, and protection for the body's organs, and facilitating movement in conjunction with muscles. The inclusion of skin, sweat glands, and hair in the integumentary system highlights the system's focus on external barriers and regulatory functions, in contrast to the skeletal system's internal supports.