Outer Duramater, Middle Arachnoid and Inner Piamater.

A neuron typically consists of three basic parts: cyton, dendrites and axon.

The pathway taken by nerve impulse to accomplish reflex action is called reflex arc.

Conditional reflexes are the result of practice and learning. Playing harmonium by striking a particular key on seeing a music note is an example of conditioned reflex which requires conscious training effort.

Hind brain is formed of three parts (1) cerebellum, (2) pons and (3) medulla oblongata.

Spinal Cord :

i) Spinal cord is a cylindrical structure lying in the neural canal of the vertebral column.
ii) It is also covered by meninges.
iii) It extends from the lower end of medulla oblongata to the first lumbar vertebra.
iv) The posterior most region of spinal cord tapers into a thin fibrous thread like structure called filum terminale.
v) Internally, the spinal cord contains a cerebrospinal fluid filled cavity known as the central canal.
vi) The grey matter of spinal cord is 'H' shaped.
vii) The upper end of letter 'H' forms posterior horns and lower end forms anterior horns.
viii) A bundle of fibres pass into the posterior horn forming dorsal or afferent root.
ix) Fibres pass outward from the anterior horn forming ventral or efferent root.
x) These two roots joins to form spinal nerves.
xi) The white matter is external and have bundle of nerve tracts.
xii) Spinal cord conducts sensory and motor impulses to and from the brain.
xiii) It controls reflex actions of the body.