Functions of the system:
Skin protects your insides, regulates body temperature, takes out toxic substances with sweat. Nails protect tips of your fingers and make it easier to scratch and itch. Hair also regulates body temperature, and protects your skin from the sun. Hair also acts as sense organs
How they work:
Skin: Skin cells work by making a protective layer on the body and act as a shield to keep out the microbes, shield it from the elements and allow the nervous system to expose sensations like hot and cold. Skin is an organ of sensation. Skin has a bunch of nerves in and on the surface. The nerve cells detect changes in the temperature. There are different receptors for heat, cold, touch, and pain. Any damage to these cells is called neuropathy, which results in loss of sensation of any type of touch or feel.
Hair: Your hair starts off growing from a root in the bottom of the follicle. Blood from blood vessels in your scalp feed the roots, which results in more cell production which makes the hair grow, your hair gets pushed through the skin on your scalp when it grows and passes through an oil gland along the way.
Nails: Nails start growing in the nail root, tucked below the cuticle. When the cells at the root of the nail start to grow, the newer nail cells push out the old nail cells. The old cells flatten and become hard, and because of Keratin, a protein made by these cells, Cuticles protect the new nail as it grows.