Question

Organize the following layers of the epidermis from Superficial to deep.

Answer 1

Layers of epidermis from Superficial to deep:

1)Stratum Corneum
2)Stratum Lucidum
3)Stratum Granulosum
4)Stratum Spinosum
5)Stratum Basale (Germinativum)

1) Stratum Corneum -(Horny Layer): The stratum corneum is the most superficial outermost layer of the epidermis and is the layer exposed to the outside environment. The increased keratinization (also called cornification) of the cells in this layer gives it its name. There are usually 15 to 30 layers of cells in the stratum corneum. This dry, dead layer helps prevent the penetration of microbes and the dehydration of underlying tissues, and provides a mechanical protection against abrasion for the more delicate, underlying layers. Cells in this layer are shed periodically and are replaced by cells pushed up from the stratum granulosum (or stratum lucidum in the case of the palms and soles of feet). The entire layer is replaced during a period of about 4 weeks.

• Accounts for three quarters of the epidermal thickness
• Functions include:
  • Waterproofing
  • Protection from abrasion and penetration
  • Rendering the body relatively insensitive to biological, chemical, and physical assaults

2) Stratum Lucidum-(Clear Layer): The stratum lucidum is a smooth, seemingly translucent layer of the epidermis located just above the stratum granulosum and below the stratum corneum. This thin layer of cells is found only in the thick skin of the palms, soles, and digits. The keratinocytes that compose the stratum lucidum are dead and flattened. These cells are densely packed with eleiden, a clear protein rich in lipids, derived from keratohyalin, which gives these cells their transparent (i.e., lucid) appearance and provides a barrier to water.

• Thin, transparent band superficial to the stratum granulosum
• Consists of a few rows of flat, dead keratinocytes

3) Stratum Granulosum - (Granular Layer): The stratum granulosum has a grainy appearance due to further changes to the keratinocytes as they are pushed from the stratum spinosum.

• Thin; three to five cell layers in which drastic changes in keratinocyte appearance
• Keratohyaline and lamellated granules accumulate in the cells of this layer

4) Stratum Spinosum (Prickly Layer): the stratum spinosum is spiny in appearance due to the protruding cell processes that join the cells via a structure called a desmosome. The desmosomes interlock with each other and strengthen the bond between the cells.

• Cells contain weblike system of intermediate filaments attached to desmosomes
• Melanin granules and Langerhans' cells are abundant in this layer

5) Stratum Basale (Basal Layer): The stratum basale (also called the stratum germinativum) is the deepest epidermal layer and attaches the epidermis to the basal lamina, below which lie the layers of the dermis.

The cells in the stratum basale bond to the dermis via intertwining collagen fibers, referred to as the basement membrane. A finger-like projection, or fold, known as thedermal papilla (plural = dermal papillae) is found in the superficial portion of the dermis

• Deepest epidermal layer firmly attached to the dermis
• Consists of a single row of the youngest keratinocytes
• Cells undergo rapid division, alternate name stratum germinativum

Source:

https://opentextbc.ca/anatomyandphysiology/chapter/5-1-layers-of-the-skin/

http://apchute.com/ap1chap/chapt5.htm