2. Describe briefly the changes that occur in keratinocytes when they migrate from the stratum basale to the stratum corneum. How is the structure of the stratum corneum related with the main functions of the epidermis? The changes that occur to in keratinocytes when they migrate from the stratum basale to the stratum corneum is in the stratum basale they divide the process known as mitosis, and the daughter cells move up away from the stratum basale and begin changing shape and composition as they undergo different stages while moving up the layers of the epidermis. The stratum basale also has another cell type called a melanocyte, which transfer melanin to keratinocytes. In the layer above the stratum basale called the stratum spinosum. It is composed of 8 to 10 layers of keratinocytes that are formed as a result of cell division that occurred in the stratum basale. The keratinocytes in this layer begins the synthesis of keratin and release a water- repelling glycolipid that prevents water loss, which makes the skin relatively waterproof. The keratinocytes have projections (artifacts) in this layer and the cells start to produce filament called tonofilaments. As new keratinocytes are produced atop the stratum basale, the keratinocytes in the stratum spinosum are then pushed into the stratum granulosum. In the next layer, the stratum granulosum, the cells become flatter and their cell membranes thicken, and they generate large amounts of keratin and keratohyalin, which accumulates as lamellar granules in the cells. When the cells die, the cell junctions (proteins) cannot survive, this make the plasma membrane die as well. The pores in the membrane and the integrity of the cell is lost and becomes flat, and the membrane eventually disintegrates. Tonofilaments mix with the