Central Nervous System
The central nervous system contains spinal cord and brain. The central role in the control of most bodily functions is done by the brain, including movements, awareness, thoughts, sensations, memory and speech. Few reflex movements can happen via spinal cord pathways without any involvement of brain structures. The spinal cord is linked to a unit of the brain called the brainstem and runs through the spinal canal. Cranial nerves exit the brainstem. Nerve roots exit the spinal cord to both sides of the body. The spinal cord carries signals back and forth between the brain and the peripheral nerves. Cerebrospinal fluid surrounds the brain and the spinal cord. It also circulates within the cavities of the central nervous system. The cerebrospinal fluid circulates between the pia matter and the arachnoid, they are the 2 meningeal layers. The outer, thicker layer serves the role of a protective shield and is called the dura matter. The basic unit of the central nervous system is the neuron. Billions of neurons permit the dissimilar parts of the body to connect with each other via spinal cord and brain. A fatty material called myelin coats nerve cells to insulate them and to allow nerves to communicate quickly. CNS disorders can affect either the brain or the spinal cord which results in psychiatric disorders or neurological disorders. The causes of CNS diseases are neurology, trauma, autoimmune disorders, infections, structural defects, degeneration and tumours. So here we focus on mood disorders, neurodegenerative diseases, schizophrenia and autism. Meningitis is generally an uncommon infection that affects the sensitive membranes termed as meninges, that cover the spinal cord and brain. Encephalitis is the inflammation of the brain which is caused by infection or allergic reactions.