And this portion contains four specialized cells that we're going to discuss in just a moment. We have carotene sites, we have melanocytes, we have Langerhon cells, and we also have Merkel cells. Now, the middle portion, the middle section of the skin, is our dermis. And this contains not only the blood vessels, the arteries and the veins, but also our excretory glands, such as our sebaceous oil gland and the sweat gland. And finally, the lower, most portion of the skin is the hypodermis, also known as the subcutaneous layer. And this layer contains not only adipose cells that insulate our body, but also macrophages cells that engulf bacterial cells.