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In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural folds become elevated, and ultimately the folds meet and coalesce in the middle line and convert the groove into the closed ...
After formation of the tube, the brain forms into three sections; the hindbrain, the midbrain, and the forebrain. The types of neuroectoderm include: Neural crest. pigment cells in the skin; ganglia of the autonomic nervous system; dorsal root ganglia. facial cartilage; aorticopulmonary septum of the developing heart and lungs; ciliary body of ...
The neural tube has a longitudinal axis called the neuraxis, from the future brain area at the cranial end, to the conus medullaris of the spinal cord at the caudal end. By the fourth week in the human embryo, at its cranial end, three swellings have formed as primary brain vesicles. [1] These vesicles form the future forebrain, midbrain, and ...
The coalescence of the neural folds occurs first in the region of the hind-brain, and from there extends forward and backward; toward the end of the third week the front opening (anterior neuropore) of the tube finally closes at the anterior end of the future brain, and forms a recess which is in contact, for a time, with the overlying ectoderm ...
The development of the nervous system in humans, or neural development, or neurodevelopment involves the studies of embryology, developmental biology, and neuroscience.These describe the cellular and molecular mechanisms by which the complex nervous system forms in humans, develops during prenatal development, and continues to develop postnatally.
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]
Because the neural tube gives rise to the brain and spinal cord any mutations at this stage in development can lead to fatal deformities like anencephaly or lifelong disabilities like spina bifida. During this time, the walls of the neural tube contain neural stem cells , which drive brain growth as they divide many times.
The mammalian nervous system is arranged with the neural tube running along an anterior to posterior axis, from nose to tail for a four-legged animal like a dog. Humans, as two-legged animals, have a bend in the neuraxis between the brain stem and the diencephalon, along with a bend in the neck, so that the eyes and the face are oriented forward.