The central nervous system of toad formed of the brain and the spinal cord. The part of the central nervous system which is enclosed within the skull, is called the brain. The brain of toad is elongated.
The middle part is thick and two ends a n-arrow and bi-laterally syrumetrical. The brain is covered by two membrane The outer thick, hard, translucent and blood vessels enriched membrane called dura matter and the inner thin membrane is called pia matter. These two membranes together are called meninges. Meninges cover the brain and spinal cord protects them.
The brain is formed of neurons or nerve cells. One neuron is joined with the other neuron by the synapse and form the nervous tissue. The outer part of the brain is formed of grey matter i.e. nerve cell bodies. The white part towards its inner side is called the white matter. This part is formed of nerve fibres. The brain and spinal cord of vertebrate animals are not solid. In its inner Part there are hollow cavities or brain ventricles. The brain cavities remain filled up with a kind of fluid.