Question 47: What constitutes the central and peripheral nervous systems? How are the components of central nervous system protected?
Answer:
Nervous system coordinates and controls the activities of the animals. Endocrine and nervous system together helps to maintain the homeostasis and also responsible for the behaviour, memories and controls all voluntary actions. There are two main subdivisions- central nervous system (includes brain and spinal cord) and Peripheral nervous system (consists of many nerve fibres including cranial nerves, spinal nerves, ganglia and sensory receptors etc.).
Diagram:
Brain is covered by cranial meninges. The outermost meninx is the dura mater which is composed of dense and irregular tissues, middle meninx is arachnoid mater and the innermost meninx is pia mater which contains cerebrospinal fluid provides cushion against the mechanical shock. Brain is enclosed in the skull which provides protection. Spinal cord is located within the vertebrate cavity of the vertebral column and spinal meninges surround the spinal cord which provides protection.
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