Question

How is keratin is formed (mixture of keratin fibers & keratohyalin)

Answer 1

Before going to this we should know about different layers of skin and where keratin is produced.

The three layers of skin are as follows:

• Epidermis
• Dermis
• Hypodermis

Further epidermis contains five sub-layers:

1. Stratum corneum

2. Stratum lucidum

3. Stratum granulosum

4. Stratum spinosum

5. Stratum basale

Keratin forms the outer layer of skin which acts as a protection membrane. We can find this keratin in hard layers like skin, nails, horns, hair, etc. Keratin is a fibrous protein that is produced from keratinocytes. Keratin fibers form a thick hard layer of skin through the process which is called keratinization. Lets discuss how this keratinization happens.

Keratinocytes are present in stratum spinosum. These cells move from the basal layer (stratum spinosum) to the outer layers of skin. During this process when it reaches Startum lucidum, the keratinofibers present in keratinocytes will forms a dense layer by cross-linking between them and these cross links will be provided with keratohyalin (produced from the third layer of the epidermis is stratum granulosum). Keratohyalin also promotes the dehydration of cells, there by forms a tightly interlocked layer of keratohyalin and keratin fibers. Then the produced keratin undergoes cornification to form a dead keratin layer.