In addition to being hairless and packed with sweat glands, palmar skin is relatively thick and keratinized. Indeed, the skin that lines the palms of a human is typically 0.8 to 1.4 millimeters thick, while most other parts of the body are only protected by an integument 0.1 millimeters thick. Within palmar skin, five morphologically discrete layers of tissue exist. The outermost layer is the stratum corneum, which is predominantly comprised of dead cells that are almost continuously sloughed from the body. As these cells are lost, new ones originate via mitosis from the innermost layer of palmar skin, the stratum basale, and gradually migrate through the other strata until they too are eventually exfoliated and replaced.