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Scientific Beauty News Letter
10. Stratum Granulosum -A delicate structure for protection!
The stratum granulosum, sometimes also known as the granular layer, is the one in the middle layer. Underneath the stratum granulosum are two layers, with the lowest one consisting of actively dividing cells, while above are two layers of flattened inactive cells with the top, outer layer constantly being shed.
The progressive maturation of a keratinocyte is charcterized by the accumulation of keratin, called keratinization. The cells of the stratum granulosum accumulate dense basophilic keratohyalin granules (seen on the close-up view). These granules contain lipids, which along with the desmosomal connections, help to form a waterproof barrier that functions to prevent fluid loss from the body.
As granulosum has visible granules, it is also known as granular layer. Among the five sublayers of epidermis of skin, granulosum is in the middle having spinosum and lucidum layers on the inner and outer sides. The stratum granulosum creates a waterproof barrier between these outer layers and the inner, live cells.
In the regions of the body, where the skin is thin, there is no clear cut differentiation between granulosum and lucidum layers. Under the microscope, they appear grainy and consists of 2-5 cell thickness. These grainy, granular or granulosum cells are the keratinocytes, which have migrated from the lower spinosum. These are the last layer of living cells which are in the process of losing their nuclei and dying.
These squamous cells have many basophilic granules called keratohyalin granules which are small and are not bound by membrane. Filaggrin, a type of protein, is found in large quantities in these cells and is believed to bundle keratin.
Lipid containing lamellar granules are present which are bound by membrane. These membrane-bound granules secrete the contents to extracellular space by exocytosis and give rise to sheets of waterproof fatty barrier. This barrier function also prevent nutrients diffusion from the lower cells, leading to death of cells.
In the stratum granulosum, the protein Keratohyalin forms dense cytoplasmic granules that promote dehydration of the cells as well as aggregation and cross-linking of the keratin fibers. The nuclei and other organelles then disintegrate, and the cells die. Further dehydration creates a tightly interlocked layer of cells that consists of keratin fibers surrounded by keratohyalin.
You must clearly understand here that the layers below this layer are the leaving layers of cells and in this layer the actual cell death occurs. The stratum granulosum and the layers above are the dead cell layers, and when it comes to skin peeling, we should actually peel the skin to this level.
When we go deep inside the skin for peeling, there is damage to the leaving cells and the results are not adequate, but when we peel the skin just till the stratum granulosum, the healing process is blocked and the easy rejuvenation can be achieved.
Credit : Rahul Phate’s
Scientific Beauty News Letter
10. Stratum Granulosum -A delicate structure for protection!
The stratum granulosum, sometimes also known as the granular layer, is the one in the middle layer. Underneath the stratum granulosum are two layers, with the lowest one consisting of actively dividing cells, while above are two layers of flattened inactive cells with the top, outer layer constantly being shed.
The progressive maturation of a keratinocyte is charcterized by the accumulation of keratin, called keratinization. The cells of the stratum granulosum accumulate dense basophilic keratohyalin granules (seen on the close-up view). These granules contain lipids, which along with the desmosomal connections, help to form a waterproof barrier that functions to prevent fluid loss from the body.
As granulosum has visible granules, it is also known as granular layer. Among the five sublayers of epidermis of skin, granulosum is in the middle having spinosum and lucidum layers on the inner and outer sides. The stratum granulosum creates a waterproof barrier between these outer layers and the inner, live cells.
In the regions of the body, where the skin is thin, there is no clear cut differentiation between granulosum and lucidum layers. Under the microscope, they appear grainy and consists of 2-5 cell thickness. These grainy, granular or granulosum cells are the keratinocytes, which have migrated from the lower spinosum. These are the last layer of living cells which are in the process of losing their nuclei and dying.
These squamous cells have many basophilic granules called keratohyalin granules which are small and are not bound by membrane. Filaggrin, a type of protein, is found in large quantities in these cells and is believed to bundle keratin.
Lipid containing lamellar granules are present which are bound by membrane. These membrane-bound granules secrete the contents to extracellular space by exocytosis and give rise to sheets of waterproof fatty barrier. This barrier function also prevent nutrients diffusion from the lower cells, leading to death of cells.
In the stratum granulosum, the protein Keratohyalin forms dense cytoplasmic granules that promote dehydration of the cells as well as aggregation and cross-linking of the keratin fibers. The nuclei and other organelles then disintegrate, and the cells die. Further dehydration creates a tightly interlocked layer of cells that consists of keratin fibers surrounded by keratohyalin.
You must clearly understand here that the layers below this layer are the leaving layers of cells and in this layer the actual cell death occurs. The stratum granulosum and the layers above are the dead cell layers, and when it comes to skin peeling, we should actually peel the skin to this level.
When we go deep inside the skin for peeling, there is damage to the leaving cells and the results are not adequate, but when we peel the skin just till the stratum granulosum, the healing process is blocked and the easy rejuvenation can be achieved.
Credit : Rahul Phate’s
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