Development & Zonation of CNS

Development and zonation of CNS

Th ectoderm on the mid-dorsal side of embryo becomes thick and Differentiated to form the Structure called neural plate above the notochord

Neutral plate invaginates to form the neural groom with both the Loferal margins as neural folds.

Both the neural folds fuse together changing the neural groove into the neural tube which aches from ectoderm and lies over the notochord from interior to posterior regions of the embryo. Therefore neural tube is ectodermal in origin. Formation of neural tube is the process called Neuro Cole.

The neural tube contains the lumen know as neuro Cole . It is opened at both the ends through the neuro pores.

Both the neuro pores get closed making the neural tube blind. The anterior part of neural tube present in the region of developing head become dilated to be known as Encephalon.

Encephalon differentiate into three region

1.Proseneephalon ( fore Brain)

2.MensCephalon ( Mid Brain)

3.Rombencephalon ( Hind Brain)

The part of neural tube posterior to the hind brain develop into the spinar cord.

The neural Cole within the Encephalon develops into ventricles brain where as in the region spinal cord it develops into central canal.

Both the ventricles and central canal are lined by Liliated cuboidal epithelium Ependyma and are filled with C.S.F.

There fore CNS is Ectodermal in origin

Zonation of C. N. S –

Brain is differentiated into three major part

Proseneephalo, (fore brain) – It is differentiated into 3 part :-

1. Rhinestone – Anterior most part develops into olfactory lobes responsible for olfactory function.

2. Telencephalon – Middle part of the fore brain and is also the largest part of the brain. It develops into large brain. It contains all the voluntary fun for and is also responsible for intelligence memory reasoning etc. It is the most important part of the brain.

3. Dienceohalon / Thalamencephalon – It is the posterior part of fore brain contains the pineal and pituitary glands on the dons of ventral sides respectively. It helps endocrine function regulatory the A. N. S


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