Which components primarily make up the central nervous system?

The central nervous system (CNS) is primarily composed of the brain and spinal cord. This system is crucial for processing information and coordinating bodily functions. The brain serves as the control center, responsible for interpreting sensory information, regulating homeostasis, and facilitating higher cognitive functions such as thought and decision-making. The spinal cord acts as a major pathway for transmitting information between the brain and the rest of the body, allowing for communication and interaction with peripheral nervous systems.

Understanding the roles of the brain and spinal cord is essential for grasping how the CNS operates within the broader context of the nervous system, which also includes the peripheral nervous system. The other components listed in the choices do not contribute to the structure or function of the central nervous system; they belong to different systems in the body, such as the circulatory system or respiratory system. This differentiation is crucial when studying anatomy and physiology as it helps in organizing the body's complex structures and functions.