Which layer of skin is made of stratified squamous keratinized epithelium and contains no blood vessels?

The correct answer is the epidermis. This outermost layer of the skin is composed of stratified squamous keratinized epithelium, which provides a protective barrier against environmental damage, pathogens, and water loss. The keratinized cells are filled with keratin, a protein that strengthens the skin and enhances its waterproof properties.

Additionally, the epidermis is avascular, meaning it contains no blood vessels. Instead, it receives nutrients and oxygen through diffusion from the underlying dermis, which is rich in blood supply. This arrangement is crucial for maintaining the structural integrity and function of the skin while allowing the higher layers to serve their protective roles efficiently.

Understanding the composition and characteristics of the epidermis is important for appreciating how the skin functions as a protective organ, as well as its role in various physiological processes.