Answer :
The nervous system is divided in two parts:
The central nervous system (CNS)
The peripheral nervous system (PNS)
1. CNS
The CNS consist of the brain and the spinal cord and its main function is to integrate and command the body. It uses the information obtained from the entire body and uses it to coordinate the organism's activity.
The brain is located inside the skull and the spinal cord is located inside the vertebrae. This helps protect the CNS.
The tissue that conform the CNS is grey matter (consists of neurone cell bodies and their dendrites, glial cells and capillaries) and white matter (host the majority of axions which are the long cords that extend from neurons).
2.PNS
The PNS consists of nerves that branch fromm the spinal cord and cover the entire body. It is formed by 12 pairs of cranial nerves, 31 pairs of spinal nerves and some small neuronal clusters called gaglia.
The PNS is the connection between the CNS and the body.
The PNS has no bone protection
Together the CNS and the PNS form the nervous system and transmit signals between the brain and the rest of the body, controlling the ability to move, breathe, see, think and many more.
The 3 accessory organs of the nervous system are:
The meninges: it is a set of 3 membranes that cover the brain and the spinal cord.
The cerebrospinal fluid: it is a lymph-like fluid that acts as a protective cushion for the CNS.
Ventricles: these are cavities that contain ependymal cells and blood vessels
