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Neurogenesis - Anatomy & Physiology (view source)
Revision as of 15:15, 26 August 2008
, 15:15, 26 August 2008→Neural Tube Regionalisation
**When the nucleus reaches the luminal side of cell, the cell undergoes mitosis.
**When the nucleus reaches the luminal side of cell, the cell undergoes mitosis.
==Neural Tube Regionalisation==
===Neural Tube Regionalisation===
*The neural tube undergoes regionalisation to define the anterior as the brain and posterior as the spinal cord.
*The neural tube undergoes regionalisation to define the anterior as the brain and posterior as the spinal cord.
*In the anterior, the neural tube swells into the three ventricles of the brain; forebrain; midbrain; and hindbrain.
*In the anterior, the neural tube swells into the three ventricles of the brain; forebrain; midbrain; and hindbrain.
**This occurs as fluid is pumped into the lumen of the neual tube.
**This occurs as fluid is pumped into the lumen of the neual tube.
**Pressure is regionalised to the anterior by occlusion of the neural tube at the base of the hindbrain. The occlusion reopens after enlargement of the ventricles.
**Pressure is regionalised to the anterior by occlusion of the neural tube at the base of the hindbrain. The occlusion reopens after enlargement of the ventricles.
===Formation of Cell Layers===
*The neural tube begins with the germinal layer which is a single cell layer thick. All cells have the capacity to undergo mitosis.
*Some cells then lose their ability to undergo mitosis. They detach from the germinal layer and move away from the lumen, to behind the germinal layer.
**This produces a new layer called the '''mantle, or intermediate layer'''.
**The germinal layer is now known as the '''ventricular layer'''.