BIO380H5 Lecture Notes - Lecture 14: Stratum Spinosum, Anatomical Terms Of Location, Stratum Basale
Document Summary
The skin consists of the epidermis and the dermis. Cytodifferentiation is when the cell differentiates after it has been restricted and determined. Histogenesis the collection of various cell types that develop specific tissues. Skin is the largest organs in the body. The skin differs depending on location, some skin has hair, while others don"t, etc. At the end of the 4th week of development, we have the one layer of ectoderm and numerous mesenchymal cells. 3rd month, we have three layers of cells, the ectoderm, and two layers of peridermal cells. At the 6th month, the peridermal cells become cornified and are eventually sloughed. When the skin is mature, the outer cells become cornified and form the epithelial cells. Some epidermal cells are not derived from the ectoderm: melanoblasts are rich with the melanin. They migrate from the neural crest during the 2nd month. Migrate into the dermis and then to the epidermis.
