Answer:
From internal to external: Stratum Basale or Basal Layer, Stratum Spinosum or the Spiny layer, Stratum Granulosum or the Granular Layer, Stratum Lucidum, Stratum Corneum.
Explanation:
Stratum Basale or Basal Layer: The deepest layer of the epidermis. The basal layer is where new skin cells known as “keratinocytes” are “born. Two other types of cells are also found here: Merkel cells and melanocytes. Merkel cells are receptors that send messages to your brain that get translated as your sense of touch.
Stratum Spinosum or the Spiny layer: This layer gives the epidermis its strength. Like its name suggests, the stratum spinosum contains spiny protrusions that hold the cells tightly together to prevent your skin from tearing and blistering.
Stratum Granulosum or the Granular Layer: This important layer has tiny granules full of components that are produced by skin cells and packaged in the granules. Keratin, which is what gives your strength, is packaged in little keratohyalin granules. Epidermal skin cells are named “keratinocytes” because they produce keratin.
Stratum Lucidum: The stratum lucidum gets its name from the fact that the granules are no longer there, so the cells look clear or lucid. This thin layer of cells is found only in the thick skin on the palms of your hands and fingers and the soles of your feet.
Stratum Corneum
: This is the outermost layer of the epidermis and is therefore exposed to the atmosphere outside of your body. The “skin barrier” that prevents evaporation of water is also located here. The entire stratum corneum layer is replaced with new cells in a process known as desquamation. New cells travel up from the basale layer where they are made and push out the old, lackluster cells on the surface.
References:
Leslie Baumann (2002). Cosmetic Dermatology: Principles and Practice
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