What type of tissue makes up each layer?
What type of tissue makes up each layer?
The four types of tissue in the body are epithelial, connective, muscle, and nervous. Epithelial tissue is made of layers of cells that cover the surfaces of the body that come into contact with the exterior world, line internal cavities, and form glands.
What type of tissue is the stratum basale?
The stratum basale is a single row of columnar or cuboidal cells resting on the basement membrane zone that separates the epidermis from the dermis (see Fig. 1-5). Most of these cells are keratinocytes that are constantly reproducing and pushing upward to replenish the epidermal cells above.
What is the stratum corneum layer made of?
keratinocytes
The stratum corneum is the outermost layer of the epidermis, and is made up of 10 to 30 thin layers of continually shedding, dead keratinocytes. The stratum corneum is also known as the “horny layer,” because its cells are toughened like an animal’s horn.
What are the cells of the stratum corneum composed of?
This layer is composed of 15–20 layers of flattened cells with no nuclei or cell organelles. Their cytoplasm shows filamentous keratin. These corneocytes are embedded in a lipid matrix composed of ceramides, cholesterol, and fatty acids. Their properties depend on the component ratio of the three major components.
Where are the lipids in the stratum corneum?
The mortar that secures everything in place is made out of lipids that have been released from tiny lamellar bodies that are present in the stratum granulosum. The lipids float into the space between the bricks and between the layers of corneocytes. The mortar is very important in protecting the lower layers of the skin.
How is the stratum corneum like a brick wall?
The stratum corneum is sometimes described as a brick wall. The corneocytes that make up the cell envelope are layers, like bricks, mortared together by lipids, that create the outer water barrier.
What causes defects in the stratum corneum layer?
In addition to pathologies secondary to lipid abnormalities, stratum corneum protein abnormalities can also result in defects in the stratum corneum layer of the epidermis. Defects in corneodesmosomes, the junctional proteins that connect corneocytes, result in diseases such as peeling skin disease.
What kind of cells are in the stratum corneum?
Stratum corneum, 20-30 cell layers, is the uppermost layer, made up of keratin and horny scales made up of dead keratinocytes, known as anucleate squamous cells. This is the layer which varies most in thickness, especially in callused skin.
How did the stratum corneum get its name?
The name itself comes from the Latin for “clear layer,” which describes the transparency of the cells themselves. The cells in the stratum corneum layer are known as corneocytes (or horny cells).
The mortar that secures everything in place is made out of lipids that have been released from tiny lamellar bodies that are present in the stratum granulosum. The lipids float into the space between the bricks and between the layers of corneocytes. The mortar is very important in protecting the lower layers of the skin.
The stratum corneum is sometimes described as a brick wall. The corneocytes that make up the cell envelope are layers, like bricks, mortared together by lipids, that create the outer water barrier.