AAMC FL Practice Exam

What is derived from the ectoderm during embryonic development?

1. Muscle tissue

2. Heart and blood vessels

3. Central nervous system and skin structures

4. Bone and connective tissues

The correct answer is: Central nervous system and skin structures

During embryonic development, the ectoderm is the outermost germ layer, which differentiates into several important structures. One of the primary derivatives of the ectoderm is the central nervous system, which includes the brain and spinal cord. This occurs through a process called neurulation, where the ectoderm thickens to form the neural tube, the precursor to the central nervous system. Additionally, the ectoderm develops skin structures, including the epidermis (the outer layer of skin) and associated elements such as hair follicles and glands. These components play critical roles in protecting the body and regulating temperature, along with sensory functions. Options related to muscle tissue, heart and blood vessels, or bone and connective tissues are inaccurate in this context, as those structures are derived from other germ layers: mesoderm primarily gives rise to muscle tissue and bone, while the endoderm contributes to the formation of the internal organs. Thus, the role of the ectoderm in forming the central nervous system and skin structures is clearly defined and central to understanding embryonic development.