Hello everyone! Welcome to my channel Today we are going to give the Embryology of the Central Nervous System first part The central nervous system appears at the beginning of the third week like a thickened slipper-shaped ectoderm plate that receives the name of Neural Plate This is located in the mid-dorsal region in front of the primitive ganglion. Its lateral edges soon rise to form the Neural Folds As the folds develop, they continue to rise come close to each other and finally merge, creating the Neural Tube The fusion begins in the cervical region and then progresses cephalad
and caudal. Once the fusion has begun, the open ends of the Neural Tube form the cranial and caudal neuropores that communicate with the overlying amniotic cavity The closure of the cranial neuropore is made in the cranial direction from the site of the initial closure in the cervical region and from a place in the forebrain that appears later The second site advances in the cranial direction to close the most rostral region of the neural tube. and in a caudal direction to join the closure that advances from the cervical site The definitive closure of the cranial neuropore
is performed in the phase of 18 to 20 somites approximately on day 25, and the closure of the caudal neuropore takes place three days later The cephalic end of the neural tube shows three dilations called primary brain vesicles one is the forebrain or forebrain, another is the midbrain or middle brain and the third is the hindbrain or posterior brain At the same time the hindbrain produces two folds The Cervical Fold at the junction of the Rhombencephalon with the Spinal Cord and the Cephalic Fold in the midbrain region Towards the 5th week of development, Primary Brain
Vesicles already differentiate into 5 Secondary Vesicles The forebrain gives rise to the telencephalon and the diencephalon The Midbrain remains and the hindbrain produces the Midbrain and the Midbrain A deep groove called the Rombencephalic Isthmus separates the Midbrain from the Midbrain and the Pontine Pleat marks the boundary between the Metancephalon and the Mylencephalon Secondary Vesicles provide a different part of the brain The main structures derived from them include in the Telencephalon the Cerebral Hemispheres in the diencephalon the optic vesicle, the thalamus, the hypothalamus and the pituitary in the midbrain, the anterior and posterior colliculi in the
metencephalon the cerebellum and the bridge and in the Myellencephalon the Oblonged Marrow The light from the Spinal Cord, called the Central Canal, continues with that of the Brain Vesicles the cavity of the hindbrain is the 4th ventricle that of the Diencephalon is the 3rd Ventricle and that of the Cerebral Hemispheres are the Lateral Ventricles The midbrain light connects the 3rd and 4th Ventricles, it narrows a lot and then it is known as Silvio Aqueduct On the other hand, the Lateral Ventricles communicate with the 3rd through the Monro Interventricular Holes And well here we come with
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