Overview of the Nervous System

The nervous system consists of the brain, spinal cord and nerves. Its function is to receive information (from both inside and outside the body), process the information and then send out commands to the body.

These commands may be conscious actions (such as moving the skeletal muscles to stand up or walk) or may be unconscious actions (such as digesting food, cardiac contractions and secreting hormones).

The Brain
The brain is split into different sections that have different functions. For example,

• the cerebrum is the center of conscious thinking, learning and memory.
• the brainstem controls breathing, heart rate and blood pressure.
• the cerebellum is responsible for balance, posture, and coordination of movement.

The Spinal Cord
The spinal cord begins at the brain and extends down, within the vertebral column. The spinal cord is the main pathway for connecting the brain with the nerves in the body.

The spinal cord does not extend down the whole length of the vertebral column, but terminates at the space in-between the first and second lumbar vertebrae. 

The Nerves
The function of nerves is to be a pathway for signals to be sent. These may be sensory signals (such as sensation of temperature or pain), or they may be command signals (such as voluntary movement). There are 31 pairs of nerves aLached to the spinal cord. 

The Meninges
The brain and spinal cord are enclosed by a 3 layered membrane called the meninges.

There is a small space between the bottom two layers (the arachnoid and pia mater) called the subarachnoid space. In this space there is cerebrospinal fluid (CSF). Cerebrospinal fluid acts as a shock absorber, which helps to protect the brain and spinal cord from injury.