Neuron Development Videos: Neurulation & Gastrulation

Class 4

Neurolation

The process during embryonic development where the neural plate forms and folds to create the neural tube, which eventually develops into the central nervous system. (Brain & Spinal Cord)

Neurolation

process in which the neural plate, a flat structure of ectodermal tissue in the vertebrate embryo, folds to form the neural tube, a hollow tube that gives rise to the brain & spinal cord

Gestation

“The period between conception & birth”

The period of development during which an embryo or fetus grows inside the womb, typically lasting about nine months in humans.

when does development of Embryonic Nervous System begin

third week of gestation

What enduces the overlying ectoderm to thicken & form the Neural plate

Central Notochrod

What is formed when the central notochord enduces the overlying ectoderm to thicken

the neural plate

What are the 3 germ layers

ectoderm, mesoderm, endoderm

The folding of what forms the neural tube?

the neural plate

The folding of the neural plate forms what?

the neural tube

Cells next to the notochord become wedge-shaped and create a hinge point called:

Medial Hinge Point

The edges of the neural plate extend upward & become what

neural folds

What is the midregion of the neural plate when the neural folds are formed?

the neural groove

Neural folds move closer and two more hinge points form called:

Dorsolateral hinge points

What is it called when the neural folds grow toward each other to fuse or touch at the midline

neural tube formation

A part of the neural fold becomes what

the neural crest

Neural Crest

a group of cells that develops from the embryonic ectoderm and gives rise to various structures in the body, including peripheral nerves and facial features.

Cranial pore close on what day and form what?

Close on Day 25 and turn into 3 primary vesicles:

forebrain:Phonsencephalon

• Telencephalon

• Diencephalon

midbrain:Mesencephalon

• Mesencephalon

hindbrain:Rhombencephalon

• Metencephalon

• Myelencephalon

Caudal pore closes on what day of embryonic development

Day 27

Failure of fully closing the neurotube properly causes what?

neural tube defects, such as spina bifida or anencephaly.

Anencephaly

Failure of the Neural tube to spontaneously close at the cranial end resulting in incomplete development of the brain and skull.

Incompatible with life

Spina bifida

Failure of the neural tube to close properly at the caudal end, leading to incomplete development of the spinal cord and surrounding structures.

What are the 4 types of Spina Bifida?

Spina Bifida Occulta, Spina Bifida w/Meningocele, Spina Bifida w/Myelomeningocele, and Spinabifida w/Myeloschisis.

Spina Bifida Occulta

asymptomatic defect caused by failure of the 2 halves of the vertebral arch to fuse @ the midline

a mild form of spina bifida where the defect is covered by skin and typically does not cause symptoms.

Spina Bifida Occulta only affects what

the vertebral arch

Spina Bifida w/meningocele

a type of spina bifida where the protective membranes around the spinal cord protrude through the opening in the spine, forming a sac filled with cerebrospinal fluid.

Meninges protude through the vertebral defects w/o protrusion of the spinal cord

Spina Bifida w/meningomyelocele

a type of spina bifida where both the protective membranes and spinal cord protrude through the opening in the spine, leading to potential neurological impairment.

Both the meninges & spinal cord are involved in the defect

Covered by the skin

Spina Bifida wmyeloschisis

a severe type of spina bifida where the spinal cord is exposed and not covered by skin or membranes, leading to significant neurological damage.

Most severe type

Gastrulation

The process where by the bilaminar embyronic disc undergoes reorganization to form a tirlaminar disc

By the end of the 2nd wk going into the 3rd wk of development what happens to the bilaminar disc?

It transforms into a trilaminar disc through gastrulation, establishing the three germ layers: ectoderm, mesoderm, and endoderm.

Primitive Streak

A structure that forms during gastrulation, marking the site of cell migration and differentiation, which leads to the establishment of the body axis and germ layers.

• Cranial end

• Caudel end

• Left side

• Right side

The primitive streak expands to create what

the primitive node, which is crucial for organizing the body plan and initiating the formation of the notochord.

Primitive Pit

The primitive node contains a circular depression known as

Primitive Groove

As the depression continues along the midline of the epiblast, towards the caudal end of the streak what is formed

Primitive groove

is a structure that forms along the midline of the embryo during gastrulation, serving as a pathway for cells to migrate into the interior of the embryo.

Invagination

is the process by which a region of the embryo folds inward to form a cavity, contributing to the development of the gut and other structures.

Definitive Endoderm

The hypoblast become completely replaced by a new proximal layer called?