Neuroanatomy

Zygote (1

cell embryo)

Blastomeres

Numerous smaller cells resulting from the mitotic divisions of the zygote.

Blastocyst

Formed when fluid enters the embryo by osmosis to create the blastocyst cavity.

Inner Cell Mass (ICM)

A small group of cells on the inside of the blastocyst.

Trophoblast (TB)

The larger group of external cells of the blastocyst that secretes enzymes to facilitate hatching.

Hatching

The process where the embryo sheds the Zona Pellucida (ZP) in the uterus.

Implantation

The attachment of the embryo to the uterine lining (endometrium).

Embryonic Folding

The process by which the trilaminar disc is rolled up to form a 3D body form.

Neural Plate

Forms from the ectoderm and folds to form the neural tube during neurulation.

Neurulation

The process where the neural plate folds to form the neural tube.

Anterior/Cranial Neuropore

The anterior opening of the neural tube which must close.

Posterior/Caudal Neuropore

The posterior opening of the neural tube which must close.

Neural Crest

Embryonic tissue that has been described as a fourth germ layer.

Neurocristopathies

Defects in neural crest development or differentiation.

Hirschprung’s disease

A neurocristopathy resulting from the failure of neural crest cells to populate the colon, leading to a lack of enteric ganglia.

Neuroblastoma

A tumour of the adrenal medulla or autonomic ganglia of the sympathetic nervous system.

Ectodermal Placodes

Thickened patches of ectoderm that develop lateral to the neural crest in the cranial region.

Placodal Cells

Cells that invaginate/delaminate from ectodermal placodes to give rise to cranial ganglia and paired sense organs.

Rhombomeres

Seven transient segments that the Metencephalon and Myelencephalon (hindbrain) are segmented into.

Myelencephalon

Gives rise to the Medulla Oblongata.

Metencephalon

Gives rise to the Pons and Cerebellum.

Medulla Oblongata

Derived from the Myelencephalon; a transitional structure between the brain and spinal cord.

Pons

Derived from the basal plate of the Metencephalon; carries tracts of nerve fibers.

Cerebellum

Derived from the alar plate of the Metencephalon; controls balance and posture.

Basal Plates

The region of the neural tube from which cranial nerve motor nuclei develop.

Alar Plates

The region of the neural tube from which cranial nerve sensory nuclei develop.

Telencephalon

Massive expansion of these bilateral vesicles forms the cerebral hemispheres.

Cerebral Cortex

The roof and walls of the Telencephalon; folds into gyri and sulci as the hemispheres grow.

Cortical Plate

A structure in the developing cerebral cortex that is populated by migrating neurons in an inside

Radial Glial Cells

Bipolar cells that neuronal progenitors migrate along from the ventricular zone towards the periphery of the developing cortex.

Neural Tube Defects (NTD)

Defects arising from issues in neural tube closure.

Spina Bifida

An NTD complication leading to neurological dysfunction of the bladder, urinary incontinence, and epilepsy.

Chiari Type II Malformation

A complication of NTD where the brain stem and cerebellum protrude downward into the spinal canal.

Folate (Natural B9)

The natural form of Vitamin B9, involved in metabolic pathways vital to cell survival and differentiation.

Folic Acid (Synthetic B9)

The synthetic form of Vitamin B9; its food fortification is the most successful preventative strategy for NTD.

Neurons

Electrically excitable cells that receive and send signals to the rest of the body.

Glia (Glial Cells)

Cells that provide metabolic and structural support to the neurons.

Ependymal Cells

Glial cells that line the brain ventricles and the central canal of the spinal cord.

Microglia

Glial cells derived from the mesoderm that act as the first and main form of active immune defense (macrophage