The skin forms a barrier that keeps harmful substances outside the body. The skin helps the body maintain a steady temperature. And the perspiration that comes out of your skin takes out wastes.
The integumentary system also works close with your circulatory system.
Because certain substances can enter in to your skin your circulatory system can help send the medications you take to fight the substances that are in your body.
And last immune system.
The immune system can send tiny oils to help the barrier of skin.