Which of the following is NOT contained within the integumentary system?

The integumentary system consists of the skin and its associated structures, which include hair and nails. The primary function of this system is to protect the body, regulate temperature, and provide sensory information. Skin serves as the largest organ and acts as the first line of defense against environmental factors.

Hair is an accessory structure of the integumentary system, providing insulation and protection, while nails protect the tips of fingers and toes and aid in grasping objects.

On the other hand, eyes are part of the visual system, which is not included in the integumentary system. Eyes are responsible for vision and are comprised of various specialized tissues and organs that enable the perception of light and images. Therefore, the answer highlights the fact that while skin, hair, and nails are integral parts of the integumentary system, eyes belong to a different physiological system entirely.