CENTRAL NEURAL SYSTEM(CNS)
The brain and spinal cord are continuous structures, which together form the CNS. They are both protected by hard bony coverings-the brain by the cranium and the spinal cord by the vertebral column and by a continuous, tough, three layered membrane of connective tissue called the meninges surface
Both the brain and spinal cord are bathed in cerebrospinal fluid (CSF), which is continuously circulated through the cerebral ventricles, the cavity of the spinal cord and the sub-arachnoid space. It serves as a pad to cushion the CNS from shocks and mechanical injuries. The CSF also carries oxygen and nutrients from the blood to the neurons and neuroglia of the CNS.
Brain
Brain is the central information processing organ of ourbody. Human brain weighs around 1.2-1.4 kg. It lies in the cranium of skull. Brain and spinal cord are surrounded by connective tissue membranes called meninges.
There are three meninges in humans, an outer layer called duramater a middle layer called arachnoid membrane and an inner thin layer called piamater.
Human brain is divided into three parts-forebrain (pros- encephalon), midbrain (mesencephalon) and hindbrain(rhombencephalon)
Forebrain
Forebrain consists of olfactory lobes, cerebrum and diencephalon Olfactory lobes are concerned with sense of smell.
Cerebrum forms the major part of the human brain. A deep cleft divides the cerebrum longitudinally into two halves, which are termed as the left and right cerebral hemispheres.
