A cylindrical structure P in our body begins in continuation with medulla and extends downwards. It is enclosed in a bony cage Q and surrounded by membranes R. As many as x pairs of nerves arise from the structure P. The structure P is involved in the reflex actions of our body and conduction of nerve impulses to and from another organ S of our body with which it forms CNS.

(a) Name the structure P.


(b) Name (i) bony cage Q, and (ii) membranes R.


(c) How much is x?


(d) Name the organ S.


(e) What are the reflexes involving structure P only known as?

(a) In above question, the structure P is spinal cord.

(b) The bony cage Q is vertebral column and membranes R is meninges.


(c) The value of X is 31.


(d) The organ S is brain.


(e) The reflexes involving structure P (Spinal cord) only are known as spinal reflexes.


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