Optometry Admission Test (OAT) Practice

Which germ layer is responsible for forming the epidermis?

1. Mesoderm

2. Endoderm

3. Ectoderm

4. Germ layer

The correct answer is: Ectoderm

The ectoderm is the germ layer responsible for forming the epidermis, which is the outermost layer of skin. During embryonic development, the ectoderm differentiates into several structures, including the skin, hair, nails, and the entire nervous system. This layer gives rise to epidermal cells that contribute to the formation of the protective outer barrier of the body. In contrast, the mesoderm primarily develops into structures such as muscles, bones, and the circulatory system, while the endoderm forms the lining of the digestive tract and other internal organs. Each germ layer has distinct roles in development, and the ectoderm's function in forming the epidermis highlights its importance in protecting the body and maintaining homeostasis.