Neurosciences refers to the branch of medicine that focuses on the nervous system. The nervous system is made of two parts:

The central nervous system (CNS) consists of your brain and spinal cord.

The peripheral nervous system consists of all your nerves outside of the brain and spinal cord, including those in your arms, legs, and trunk of the body. Your peripheral nervous system is divided into two parts:

  • Autonomic nervous system (ANS). This controls your internal body processes such as blood pressure, breathing, digestion, and so on.
  • Somatic nervous system (SNS). This controls your muscles and sends signals from your ears, eyes, mouth, and skin to your CNS.

Together, your brain and spinal cord serve as the main "processing center" for the entire nervous system, and control all the functions of your body. Your brain defines who you are. It is also responsible for all of your thoughts, emotions, memories, and behaviors.