Answer
The epidermis may have up to five layers. These are from outside in are the stratum corneum ( s corneum), the stratum lucidum (s. lucidum), the strautum granulosum (s. granulosum), the stratum spinosum ( s. spinosum) ,and the stratum basale ( s. basale, also called stratum germinativum):
The stratum corneum may be as many as 30 layers ( of keratinized cells) layers thick-- the number of layers varying from place to place . This layer is thicker over the soles of e palms and soles. The stratum lucid is a clear colorless layer of dead cells; it is found only in thick skin. Stratum granulosum may be two to five layers thick --there are are more layers in thick skin.
Work Step by Step
The thickness of skin may vary dramatically from place to place on the body. Some of this variation is actually due to differences in thickness of the dermis. However, when anatomist differentiate between thick and thin skin, only epidermal features are used as criteria.
The following are the features of thick skin. Thick skin is found on the palms and soles and the palmar surfaces of digits. In this kind of skin, stratum lucidum is always present and the s. corneum and s. spinosum layers are thicker than they are in thin skin. There are no hair follicle or sebaceous glands in thick skin, but there is an abundance of sudo-
riferous (sweat) glands. Epidermal ridges are also important features of thick skin.
The skin over the rest of the body is classified as thin skin. In this kind of skin the s.lucidum layer is missing, and the s.corneum and s. spinosum layers are thinner than they are in thick skin. Thin skin has hair follicles, arrector pili muscles, sebaceous glands an abundance of cutaneous sense receptors.
