The secretory portion is found in the dermis, the middle layer of the skin. Sometimes it's also found in the hypodermis, the deepest layer of our skin. The secretory portion of a sweat gland is a twisted and coiled tube that has an opening at its very top.
Molecules that cannot cross the membrane bind to receptors in the membrane. When the signal binds to a receptor changes it's shape. Other Molecules inside the cell respond to the chainging shape of the receptor.
