How are Nervous Organs Protected
Both brain and spinal cord are delicate structures which are very efficiently protected. First of all they lie in a fluid balloon. A bony covering occurs over the same. it is cranium (= brain box) of skull in case of brain and vertebral column or backbone in case of spinal cord.
Fluid present inside and outside CNS is called cerebrospinal fluid. It is filtered out blood and performs all the functions of the blood. Additionally it provides protection from shock. Three types of protective coverings or meninges occur around the brain and spinal cord-outer dura mater, middle arachnoid and inner piamater. Piamater is in contact with the surface of brain and spinal cord while dura mater is in contact with the bony covering. Cerebrospinal fluid is present between arachnoid and piamater.