The initial step in the synthesis of the hormone known as vitamin D demonstrates the interaction of multiple organ systems as in this example where the system requires proper functioning of the integumentary system.

Endocrine system

Explanation: The integumentary system is that is made up of the skin, hair, nails and the Endocrine glands. The following functions of the integumentary system are:

a. It protects skin from any form of damage which could be in form dehydration.

b. It protects the skin by secreting an hormone called melanin which protects the skin from ultra violet radiation.

c. The integumentary system helps in regulating and maintaining the body temperature

d. The skin which is part of the integumentary system secretes Vitamin D which is an essential in building of strong and healthy bones.

not only is it colder, it also becomes darker, less salty, and more dense.