This constitutes about 2.4% of the body weight of man viz.
Brain-1400 gram
Spinal nerve-150 gram
Spinal cord-30 gram
Cranial nerve-10 gram
C.S.F. is altogether not present in nervous tissue. About half of the solid nervous tissue is lipid and 40% is constituted by proteins.
Nervous tissue is composed of two dissimilar types of cells-
(1) The excitable cells are nerve cells /neuron.
(2) The non-excitable cells are neuroglial cells.