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Neuroectoderm (or neural ectoderm or neural tube epithelium) consists of cells derived from the ectoderm. Formation of the neuroectoderm is the first step in the development of the nervous system . [ 1 ]
Neuroepithelial cells of the ectoderm begin multiplying rapidly and fold in forming the neural plate, which invaginates during the fourth week of embryonic growth and forms the neural tube. [2] The formation of the neural tube polarizes the neuroepithelial cells by orienting the apical side of the cell to face inward, which later becomes the ...
The neural tube develops in two ways: primary neurulation and secondary neurulation. Primary neurulation divides the ectoderm into three cell types: The internally located neural tube; The externally located epidermis; The neural crest cells, which develop in the region between the neural tube and epidermis but then migrate to new locations
The neural tube cells give rise to the central nervous system, neural crest cells give rise to the peripheral and enteric nervous system, melanocytes, and facial cartilage, and the epidermal region will give rise to the epidermis, hair, nails, sebaceous glands, olfactory and oral epithelium, and eyes.
Failure of neurulation, especially failure of closure of the neural tube are among the most common and disabling birth defects in humans, occurring in roughly 1 in every 500 live births. [42] Failure of the rostral end of the neural tube to close results in anencephaly, or lack of brain development, and is most often fatal. [43]
1.3 Neural tube. 1.3.1 Central nervous system. 1.3.2 Pineal gland. 2 Cells derived from mesoderm. Toggle Cells derived from mesoderm subsection. 2.1 Paraxial mesoderm.
In these maps there are cells which have a preference to a certain orientation, the maximum firing rate of the cell will be achieved at that preference. As the orientation is moved away from the firing rate will drop. An orientation map is topographic because neighboring neural tissues have similar orientation preferences.
It also forms the lining cells of all the glands which open into the digestive tract, including those of the liver and pancreas; the epithelium of the auditory tube and tympanic cavity; the trachea, bronchi, and alveoli of the lungs; the bladder and part of the urethra; and the follicle lining of the thyroid gland and thymus.