It can excrete water to the skin surface via diffusion. Waste products such as urea, salt, such as sodium and water can all be excreted via the process of sweating, as well as via trans epidermal water loss. Now, function number five is that in immunity. So earlier we mentioned two types of immune cells. We mentioned Langerhon cells, which are cells found within the epidermis. And Langerhon cells are responsible for interacting with T cells of our immune system.