neural tube

Examples of neural tube in the following topics:

• Embryonic Development

  • The spinal cord derives from the neural tube in two processes: primary and secondary neurulation.
  • 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 a closed tube, the neural tube or neural canal, the ectodermal wall of which forms the rudiment of the nervous system.
  • The neural folds pinch in towards the midline of the embryo and fuse together to form the neural tube.
  • For a short time, the neural tube is open both cranially and caudally.
  • At the dorsal end of the neural tube, BMPs are responsible for neuronal patterning.

• Development of the Peripheral Nervous System

  • The peripheral nervous system develops from two strips of tissue called the neural crest, running lengthwise above the neural tube.
  • At this point the future CNS appears as a cylindrical structure called the neural tube, whereas the future PNS appears as two strips of tissue called the neural crest, running lengthwise above the neural tube.
  • The sequence of stages from neural plate to neural tube and neural crest is known as neurulation .
  • During neurulation, the borders of the neural plate, also known as the neural folds, converge at the dorsal midline to form the neural tube.
  • The neural tube will give rise to the central nervous system, while the neural crest will give rise to the peripheral nervous system.

• Neurulation

  • Following gastrulation, the neurulation process develops the neural tube in the ectoderm, above the notochord of the mesoderm.
  • Neurulation is the formation of the neural tube from the ectoderm of the embryo.
  • Beginning in the future neck region, the neural folds of this groove close to create the neural tube (this form of neurulation is called primary neurulation).
  • By the end of the fourth week of gestation, the open ends of the neural tube (the neuropores) close off.
  • Transverse sections that show the progression of the neural plate into the neural tube.

• Anencephaly

  • Anencephaly (absence of forebrain and neocortex) is a neural tube defect occurring during embryonic development.
  • Anencephaly is a cephalic disorder that results from a neural tube defect that occurs when the cephalic (head) end of the neural tube fails to close, usually between the 23rd and 26th day of pregnancy, resulting in the absence of a major portion of the brain, skull, and scalp.
  • Studies show that a woman who has had one child with a neural tube defect such as anencephaly has about a 3% risk of having another child with a neural tube defect, as opposed to the background rate of 0.1% occurrence in the population at large.
  • Genetic counseling is usually offered to women at a higher risk of having a child with a neural tube defect.
  • Anencephaly is a cephalic disorder that results from a neural tube defect that occurs when the cephalic (head) end of the neural tube fails to close.

• Development of Vision

  • The eye forms from the neural tube, epidermis, and the periocular mesenchyme, with sequential inductions of tissue during development.
  • The eye develops from the neural tube, the epidermis, and the periocular mesenchyme, which receives contributions from both the neural crest and mesoderm lineages.
  • Neural tube: First, there is an outpocketing of the neural tube called optic vesicles .
  • The pigmented retina is formed by rods and cones and composed of small cilia typical of the ependymal epithelium of the neural tube.
  • The eyes make their appearance before the closure of the anterior end of the neural tube.

• Spina Bifida

  • Spina bifida is a developmental congenital disorder caused by the incomplete closing of the embryonic neural tube.
  • Spina bifida (Latin: "split spine") is a developmental congenital disorder caused by the incomplete closing of the embryonic neural tube.
  • Neural tube defects can usually be detected during pregnancy by testing the mother's blood (AFP screening) or by a detailed fetal ultrasound.

• Embryonic Development of the Brain

  • Neurulation is the formation of the neural tube from the ectoderm of the embryo.
  • Beginning in the future neck region, the neural folds of this groove close to create the neural tube (this form of neurulation is called primary neurulation).
  • The anterior (front) part of the neural tube is called the basal plate; the posterior (rear) part is called the alar plate.
  • By the end of the fourth week of gestation, the open ends of the neural tube (the neuropores) close off.
  • Late in the fourth week, the superior part of the neural tube flexes at the level of the future midbrain—the mesencephalon .

• Fourth Week of Development

  • The fourth week of gestation is characterized by the flexion of the superior portion of the neural tube to create the mesencephalon.
  • At the end of the fourth week the yolk sac presents the appearance of a small pear-shaped vesicle (the umbilical vesicle) opening into the digestive tube by a long narrow tube, the vitelline duct.
  • Late in the fourth week of gestation, the superior part of the neural tube flexes at the level of the future midbrain, the mesencephalon.

• Development of Nervous Tissue

  • Embryonic neural development includes the birth and differentiation of neurons from stem cell precursors.
  • As development proceeds, a fold called the neural groove appears along the midline.
  • At this point the future CNS appears as a cylindrical structure called the neural tube, whereas the future PNS appears as two strips of tissue called the neural crest, running lengthwise above the neural tube.
  • The sequence of stages from neural plate to neural tube and neural crest is known as neurulation.
  • Induction of neural tissues causes formation of neural precursor cells, called neuroblasts.

• Development of the Central Nervous System

  • The CNS originally develops from a longitudinal groove on the neural plate that forms the rudimentary nervous system.
  • During early development of the vertebrate embryo, a longitudinal groove on the neural plate gradually deepens and the ridges on either side of it (the neural folds) become elevated and ultimately meet, transforming the groove into a closed tube, the ectodermal wall of which forms the rudiment of the nervous system.
  • This tube initially differentiates into three vesicles (pockets): the prosencephalon at the front, the mesencephalon, and between the mesencephalon and the spinal cord, the rhombencephalon.
  • Development of the neural tube in human embryos (Prentiss-Arey).