Final answer:
The most superficial layer of the integument is the stratum corneum, which is part of the epidermis and provides protection against environmental threats and dehydration. It is replaced every 4 weeks as dead cells are shed and new cells are pushed up from the stratum granulosum.
Step-by-step explanation:
The most superficial layer of the integument, or skin, is the stratum corneum. This layer is part of the epidermis, which is the outermost layer of the skin, exposed to the external environment. The stratum corneum is composed of 15 to 30 layers of dead cells that have undergone keratinization, also known as cornification. These cells provide mechanical protection against abrasion, prevent microbial penetration, and reduce dehydration of underlying tissues. The cells in this layer are continuously shed and are replaced by new cells from the lower layer, the stratum granulosum.
The epidermis consists of multiple layers, beginning with the deepest stratum basale, followed by the stratum spinosum, stratum granulosum, and in certain parts of the body like palms and soles, the stratum lucidum. The epidermis is attached to the dermis via the basement membrane. The dermis itself contains the blood vessels and living cells and is situated above the hypodermis, a deeper layer of skin.