Question

The tough superficial layer of the epidermis is known as the stratum. True or False

Answer 1

Answer:

True

Explanation:

The epidermis is the outermost layer of the skin, being formed by epithelial tissue. The epidermis is made up of five layers: Stratum corneum, lucid stratum, granular stratum, spinous stratum and stratum basale.

Each layer has specific functions and characteristics:

• Stratum corneum: This is the outermost layer of the epidermis, being formed by dead cells, without nuclei and flattened. The cells have a large amount of keratin and are continually flaking.
• Lucid stratum: Commonly more evident in thick skin (palms and soles), but in regions of the body where the skin is very thin it is not possible to notice its presence.  It consists of a layer of flat, eosinophilic and translucent cells.
• Granular stratum:  Consists of 3 to 5 layers of flattened polygonal cells with central nucleus and accumulated cytoplasm of basophil granules (keratin-hyaline granules), which will give rise to keratin.
• Spinous stratum: Consists of 5 to 10 layers of flattened cuboid cells with a central nucleus. The cells of this stratum have cytoplasmic projections with keratin filaments, which hold the cells together due to the presence of desmosomes. This whole arrangement gives a "Thorn" aspect to this stratum.
• Stratum basale: This is the germ layer, the deepest layer of the epidermis and in contact with the dermis.  This layer is responsible for epidermal renewal, presenting intense mitotic activity. The produced keratinocytes are constantly pushed to the upper layers and increase their keratin production. It takes up to 26 days for a basal cell to reach the stratum corneum, at which point it matures.