BGDA Lecture - Development of the Nervous System

From Embryology
Embryology - 22 Sep 2017    Facebook link Pinterest link Twitter link  Expand to Translate  
Google Translate - select your language from the list shown below (this will open a new external page)

العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt    These external translations are automated and may not be accurate. (More? About Translations)

Introduction

Adult brain animation 01.gif Neural development is a complex and ongoing process that commences in week 3 and continues through into the postnatal period. This lecture will introduce concepts about the timing, origin and abnormalities of the nervous system.

Final lecture content will be added to this current page, the linked online textbook chapters are available as pre-reading for this lecture.

2017 Lecture PDF

Aim

To develop an understanding of the development of the nervous system and the consequences of abnormal development.


Draft Lecture Timetable - Monday 29 May 2017 09:00 AM - 10:00 AM Development of the nervous system Kensington - Rex Vowels Theatre

Textbooks

Textbooks  

UNSW Embryology

Logo.png Hill, M.A. (2017). UNSW Embryology (17th ed.) Retrieved September 22, 2017, from https://embryology.med.unsw.edu.au
Neural Links: Introduction | Ventricular System | Stage 22 | Gliogenesis | Fetal | Medicine Lecture - Neural | Lecture - Ectoderm | Lecture - Neural Crest | Lab - Early Neural | Neural Crest | Sensory | Abnormalities | Folic Acid | Iodine Deficiency | Fetal Alcohol Syndrome | Postnatal | Postnatal - Neural Examination | Histology | Historic Neural | Category:Neural

The Developing Human: Clinically Oriented Embryology

Moore, K.L., Persaud, T.V.N. & Torchia, M.G. (2015). The developing human: clinically oriented embryology (10th ed.). Philadelphia: Saunders. (links only function with UNSW connection)

The Developing Human, 10th edn.jpg
The Developing Human: Clinically Oriented Embryology (10th edn) 
The Developing Human, 10th edn.jpg

UNSW Students have online access to the current 10th edn. through the UNSW Library subscription (with student Zpass log-in).


APA Citation: Moore, K.L., Persaud, T.V.N. & Torchia, M.G. (2015). The developing human: clinically oriented embryology (10th ed.). Philadelphia: Saunders.

Links: UNSW Embryology Textbooks | Embryology Textbooks | UNSW Library
  1. Introduction to the Developing Human
  2. First Week of Human Development
  3. Second Week of Human Development
  4. Third Week of Human Development
  5. Fourth to Eighth Weeks of Human Development
  6. Fetal Period
  7. Placenta and Fetal Membranes
  8. Body Cavities and Diaphragm
  9. Pharyngeal Apparatus, Face, and Neck
  10. Respiratory System
  11. Alimentary System
  12. Urogenital System
  13. Cardiovascular System
  14. Skeletal System
  15. Muscular System
  16. Development of Limbs
  17. Nervous System
  18. Development of Eyes and Ears
  19. Integumentary System
  20. Human Birth Defects
  21. Common Signaling Pathways Used During Development
  22. Appendix : Discussion of Clinically Oriented Problems

Larsen's Human Embryology

Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R., Francis-West, P.H. & Philippa H. (2015). Larsen's human embryology (5th ed.). New York; Edinburgh: Churchill Livingstone.(links only function with UNSW connection)

Larsen's human embryology 5th ed.jpg
Larsen's Human Embryology (5th edn) 
Larsen's human embryology 5th ed.jpg
UNSW students have full access to this textbook edition through UNSW Library subscription (with student Zpass log-in).


APA Citation: Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R., Francis-West, P.H. & Philippa H. (2015). Larsen's human embryology (5th ed.). New York; Edinburgh: Churchill Livingstone.

Links: UNSW Embryology Textbooks | Embryology Textbooks | UNSW Library
  1. Gametogenesis, Fertilization, and First Week
  2. Second Week: Becoming Bilaminar and Fully Implanting
  3. Third Week: Becoming Trilaminar and Establishing Body Axes
  4. Fourth Week: Forming the Embryo
  5. Principles and Mechanisms of Morphogenesis and Dysmorphogenesis
  6. Fetal Development and the Fetus as Patient
  7. Development of the Skin and Its Derivatives
  8. Development of the Musculoskeletal System
  9. Development of the Central Nervous System
  10. Development of the Peripheral Nervous System
  11. Development of the Respiratory System and Body Cavities
  12. Development of the Heart
  13. Development of the Vasculature
  14. Development of the Gastrointestinal Tract
  15. Development of the Urinary System
  16. Development of the Reproductive System
  17. Development of the Pharyngeal Apparatus and Face
  18. Development of the Ears
  19. Development of the Eyes
  20. Development of the Limbs

Neuroscience

Neuroscience 2001.jpg Purves D, Augustine GJ, Fitzpatrick D, et al., editors. Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001. Available from: https://www.ncbi.nlm.nih.gov/books/NBK10799/

More Textbooks?

Week 3

Ectoderm

  • neural plate - midline (columnar cells)
    • neural crest - outside lateral edges of neural plate
  • surface ectoderm - lateral (cuboidal cells)
    • head - sensory and anterior pituitary (placodes)
    • integument - epidermis of skin, hair, glands, teeth enamel

Neural Plate

  • extends from buccopharyngeal membrane (oral membrane) to primitive node (Hensen's node)
  • forms above notochord and paraxial mesoderm
  • neuroectodermal cells - neural plate, neural crest
  • rostrocaudal width
    • brain plate (broad)
    • spinal cord (narrow)
Mesoderm-cartoon1.jpg
Week 3 Movies
Neuralplate 001 icon.jpg
 ‎‎Neural Plate
Page | Play

Week 4

Neural Tube

neural groove neural tube and neural crest
Mesoderm-cartoon3.jpg Mesoderm-cartoon4.jpg
Stage 10 - Dorsal View

Stage10 bf10.jpg

 ‎‎Mobile | Desktop | Original

Stage 10 | Embryo Slides
Stage10 neural sm.jpg
Week 4 Movies
Neuraltube 001 icon.jpg
 ‎‎Neural Tube
Page | Play
Mouse neural tube 01 movie icon.jpg
 ‎‎Neural Tube Close
Page | Play

Neural Crest

Human embryo week 4 neural crest cells

Human embryo neural crest cells (Week 4, stage 11)

BaxterBoyd1939-fig07.jpg

Neural crest (acoustico-facial primordium)

Chicken neural crest cell migration into pharyngeal arches.

Cartoon shows example of some neural crest medial migration and structures formed at the level of the body.
  • Cells staying dorsal to neural tube - dorsal root ganglia (DRG)
  • Cells migrating ventral to neural tube - sympathetic ganglia
  • Cells migrating peritoneal cavity wall - adrenal medulla
  • Cells migrate into GIT wall - enteric nervous system


Adrenal medulla.jpg
 ‎‎Adrenal Medulla
Page | Play
Neural Crest Origin
System Cell Type
Peripheral Nervous System
(PNS)
Neurons - sensory ganglia, sympathetic and parasympathetic ganglia, enteric nervous system, and plexuses

Neuroglial cells, olfactory ensheathing cells[1]

Schwann cells[2]

Endocrine Adrenal medulla
Calcitonin-secreting cells
Carotid body type I cells
Integumentary Epidermal pigment cells
Facial cartilage and bone Facial and anterior ventral skull cartilage and bones
Sensory Inner ear, corneal endothelium and stroma
Connective tissue Tooth papillae

smooth muscle, and adipose tissue of skin of head and neck

Connective tissue of meninges, salivary, lachrymal, thymus, thyroid, and pituitary glands

Connective tissue and smooth muscle in arteries of aortic arch origin

Links: Neural Crest Development | Category:Neural Crest | Neural Crest collapsible table

Neural Crest Development

Primary Brain Vesicles

Traditional vesicle description (simplified name and alternate neuromere description in brackets)

CNS primary vesicles.jpg

Brain

  1. Prosencephalon (forebrain, prosomeres)
  2. Mesencephalon (midbrain, mesomeres)
  3. Rhombencephalon (hindbrain, rhombomeres)
Stage 13 image 053.jpg Stage 13 image 054.jpg

Spinal Cord

Stage11 sem10.jpgStage11 sem101.jpg

Neural Tube Regions  
Neural Tube Early Structures
Neural Tube (stage 11) Regions Anatomical location Patterning region
Stage11 sem102.jpg roof plate dorsal surface ectoderm
alar plate dorsal lateral surface ectoderm
basal plate ventral lateral notochord and floor plate
floor plate ventral notochord

Table above shows the future transient regions that develop from the early neural tube.

Links: Spinal Cord

Week 5

Secondary Brain Vesicles

CNS secondary vesicles.jpg

  1. Telencephalon
  2. Diencephalon
  3. Mesencephalon
  4. Metencephalon
  5. Myelencephalon

Brain Flexures

Stage 13 image 098.jpg Rapid growth folds the neural tube forming 3 brain flexures (cranial to caudal)
  • cephalic flexure - (mesencephalic) pushes mesencephalon upwards
  • pontine flexure - generates 4th ventricle (cerebellum will grow into this space)
  • cervical flexure - between brain stem and spinal cord

Ventricles

  • cavity within neural tube will form the contiguious space of the ventricules of the brain and central canal of spinal cord
  • space is filled initially with amniotic fluid, later with CerebroSpinal Fluid (CSF)
  • CSF is secreted by
    • chorioid plexus modified vascular structures lying within the ventricles
      • floor of lateral ventricle and roof of the third and fourth ventricles
    • ventricular ependymal cells and cells lining the subarachnoid space
  • CSF also fills the subarachnoid space (between arachnoid mater and pia mater).
Adult Ventricular Structures  
Brain four ventricles and several foramina (openings that connect ventricular spaces)
  • 2 lateral ventricles (right and left)
    • interventricular foramina (foramina of Monro)
  • third ventricle
    • cerebral aqueduct (Sylvius)
  • fourth ventricle
    • median aperture (Magendie) subarachnoid space via the cisterna magna
    • right and left lateral aperture (Luschka) subarachnoid space via the cistern of great cerebral vein

Spinal cord

  • central canal lined with ependymal cells

Spinal cord histology 10.jpg

Adult Meninges Layers  
Meninges cartoon.jpg
Links: Neural - Ventricular System Development
Csf cartoon2.jpg

CSF-filled spaces in adult brain.

Week 6

Movie

Human embryo tomography Carnegie stage 17.jpg

Note the shape and size of the different regions of the brain and spinal cord.

  • Telencephalon (cerebrum) has begun to expand and will eventually cover the midbrain region.
  • Dorsal root ganglia are visible outside the spinal cord.

Week 8

The human MRI movie below (head, sagittal plane, left to right) shows the central nervous system (CNS) development at the end of the embryonic period (week 8; GA week 10).

Stage23 MRI S01 icon.jpg
 ‎‎Sagittal Head
Page | Play
Stage23 MRI 3D02 icon.jpg
 ‎‎Embryo CNS
Page | Play
Stage23 MRI S02 icon.jpg
 ‎‎Sagittal Embryo
Page | Play
Stage23 MRI T01 icon.jpg
 ‎‎Trans. Embryo
Page | Play
Stage23 MRI C01 icon.jpg
 ‎‎Coronal Embryo
Page | Play

Cortex

Stage 22 image 217.jpg

Week 8 Developing Cortex  
Human embryo, Week 8, (GA week 10) Carnegie stage 22 section from the neural tube at the level of the developing cortex. Inset (upper right) shows whole section overview and approximate level of section (red line). Grey box shows detailed image region of developing cerebrum layer thicknesses are shown in microns.

Developing Cortex will form from the thin outer layer called the cortical plate. The underlying layers transient structures that continue to supply cells to the cortex through fetal period, most of these layers will eventually be lost, except for a thin ventricular layer. Cells migrate out along radial glia that establish the initial columnar and layered structure of the cortex. Layers are named according to the nervous system revised terminology (1970)[3]

Developing Vascular blood vessels can also be seen spanning the developing layers. In the adult, these vessels will be lined with non-fenestrated endothelial cells that together with other vascular cells (pericytes and vascular smooth muscle cells), glial cells (astrocytes and microglia) and neurons will form the "blood-brain barrier".

Developing Ventricular Space is cerebrospinal fluid (CSF) filled and the lateral ventricles form within the cortical region. The inset image shows lying within the lateral ventricles, the choroid plexus the modified vascular structure that forms and secretes the CSF.

Developing Meninges layers lie outside the neural tube. The thin pia mater that closely covers the entire brain. The mesh-like arachnoid mater and the sub-arachnoid space that will also be CSF filled. The dense dura mater lies outside these 2 layers and under the skull, it cannot be seen in the enlarged image.

Spinal Cord

Human Stage22 spinal cord02.jpg

Week 8 Developing Spinal Cord (virtual slide) 
Stage 22 - Spinal Cord (rotated)

Human Stage22 spinal cord03.jpg

 ‎‎Mobile | Desktop | Original

Stage 22 | Embryo Slides
These listed features link to zoomed views of the virtual slide with the named feature generally in the centre of the view.

Use the (-) at the top left of the screen to see where this feature is located.

Spinal Cord Features Other Features

Fetal

Second Trimester

Human week 10 fetus 01.jpg

Human week 10 fetus

Brain ventricles and ganglia development 03.jpg Brain fissure development 02.jpg
Brain and Ventricular Development[4] Brain Fissure Development[4]
Sylvian Fissure Development 

Third Trimester

Dev anat 01.jpg

The brain goes from a smooth surface to begin to fold.

  • Folds occur as millions of cells push into the cortex, increasing the surface area.
  • groove - fissure (plural, fissures).
  • fold - gyrus (plural, gyri).
Human Fetus CRL240mm brain.jpg

Human Fetus (CRL 240mm) Brain

Human Brain Growth  
Embryonic
Table below shows a direct comparison of brain growth in size between week 4 to 8 (GA 6-10)
Embryonic Central Nervous System
Stage 13 Stage 14 Stage 16 Stage 21
Human Stage13 sagittal upper half01.jpg

scale bar = 1 mm

Human Stage14 neural01.jpg Human Stage16 neural03.jpg Human Stage21 neural01.jpg
Week 4 Week 5 Week 6 Week 8
Fetal
Human brain growth 01.jpg
Adult
Adult human brain.jpg
Adult CNS Structures
Neural Tube Primary Vesicles Secondary Vesicles Adult Structures
week 3 week 4 week 5 adult
neural plate
neural groove
neural tube

Brain
Prosencephalon Telencephalon Rhinencephalon, Amygdala, Hippocampus, Cerebrum (Cortex), Hypothalamus, Pituitary | Basal Ganglia, lateral ventricles
Diencephalon Epithalamus, Thalamus, Subthalamus, Pineal, third ventricle
Mesencephalon Mesencephalon Tectum, Cerebral peduncle, Pretectum, cerebral aqueduct
Rhombencephalon Metencephalon Pons, Cerebellum
Myelencephalon Medulla Oblongata
Spinal Cord

Fetal Timeline

Neural-development.jpg

Electrical Activity Myelination
  • Cerebral cortex has no neuronal connections at end of first trimester GA 12 weeks.
  • Electroencephalogram (EEG) activity first seen in third trimester GA 7 months.
Myelination animation.gif

Myelination process occurs both in the CNS (from neural tube glia) and also in peripheral nerves (from neural crest Schwann cells).

Postnatal

WHO motor development milestones

Neural Exam Movies

Movies

Neural Development
Neuralplate 001 icon.jpg
 ‎‎Neural Plate
Page | Play
Neuraltube 001 icon.jpg
 ‎‎Neural Tube
Page | Play
Secondary neurulation 01 icon.jpg
 ‎‎Secondary Neurulation
Page | Play
Stage13-CNS-icon.jpg
 ‎‎Stage 13 Neural
Page | Play
Stage13 MRI 3D02 icon.jpg
 ‎‎Embryo CNS
Page | Play
Mouse neural tube 01 movie icon.jpg
 ‎‎Neural Tube Close
Page | Play
Stage16 MRI 3D02 icon.jpg
 ‎‎Embryo CNS
Page | Play
Stage16 MRI S01 icon.jpg
 ‎‎Embryo Stage 16
Page | Play
Human embryo tomography Carnegie stage 17.jpg
 ‎‎Stage 17 Embryo
Page | Play
Stage22-CNS-icon.jpg
 ‎‎Stage 22 Neural
Page | Play
Stage23 MRI 3D02 icon.jpg
 ‎‎Embryo CNS
Page | Play
Stage23 MRI S01 icon.jpg
 ‎‎Sagittal Head
Page | Play
Abnormalities Ultrasound
Brain fissure development 03.jpg
 ‎‎Sylvian Fissure
Page | Play
Adult human brain tomography.jpg
 ‎‎Adult Brain
Page | Play
US Dandy-Walker 01.jpg
 ‎‎Dandy-Walker
Page | Play
US Spina bifida GA19week.jpg
 ‎‎Spina Bifida
Page | Play
Fetal-Brain-icon.jpg
 ‎‎Neural
Page | Play


Fetal-Brain-icon.jpg
 ‎‎Neural
Page | Play

Abnormalities

There are a large number of different neural abnormalities associated with genetic, environmental and unknown causes. These can also involve several different systems including: neural tube, neural crest, sensory development, ventricular and vascular system development.

It would be difficult to cover all in this current lecture so a few examples are given and students should explore the topic more widely themselves.

Links: Neural System - Abnormalities | Neural Crest Abnormalities | Ventricular Abnormalities
Abnormal81-92-neuron.png

Environmental

Human-critical periods of development.jpg The long time course of neural development (week 3 through to postnatal) also means that a large number of different environmental factors, including dietary deficiency, can impact upon its development and also have a range of different effects.

Postnatal Neural Assessment - there are several basic clinical motor assessments that can identify normal and abnormal development.


Abnormality Links  
Abnormality Links: Introduction | Genetic | Environmental | Unknown | Teratogens | Cardiovascular | Coelomic Cavity | Endocrine | Gastrointestinal Tract | Genital | Head | Integumentary | Musculoskeletal | Limb | Neural | Neural Crest | Renal | Respiratory | Placenta | Sensory | Hearing | Vision | Twinning | Developmental Origins of Health and Disease | ICD-10
Historic Embryology  
1915 Congenital Cardiac Disease | 1917 Frequency of Anomalies in Human Embryos | 1920 Hydatiform Degeneration Tubal Pregnancy | 1921 Anencephalic Embryo
Environmental Links: Introduction | Low Folic Acid | Iodine Deficiency | Nutrition | Drugs | Australian Drug Categories | USA Drug Categories | Thalidomide | Herbal Drugs | Illegal Drugs | Smoking | Fetal Alcohol Syndrome | TORCH Infections | Viral Infection | Bacterial Infection | Zoonotic Infection | Toxoplasmosis | Malaria | Maternal Diabetes | Maternal Hypertension | Maternal Hyperthermia | Maternal Inflammation | Maternal Obesity | Hypoxia | Biological Toxins | Chemicals | Heavy Metals | Radiation | Prenatal Diagnosis | Neonatal Diagnosis | International Classification of Diseases | Fetal Origins Hypothesis
Links: Nutrition | Folate Deficiency | Iodine Deficiency | Neural System - Abnormalities | Axial Skeleton Abnormalities
Bacterial Links: Syphilis | Gonorrhea | Tuberculosis | Listeria | TORCH Infections | Environmental | Category:Bacteria
Viral Links: TORCH Infections | Cytomegalovirus | Hepatitis Virus | HIV | Parvovirus | Polio Virus | Rubella Virus | Chickenpox | Lymphocytic Choriomeningitis Virus | Zika Virus | Vaccination | Environmental
Genetic Links: Introduction | Genetic risk maternal age | Trisomy 21 | Trisomy 18 | Trisomy 13 | Trisomy X | Monosomy | Fragile X | Williams | Alagille | Philadelphia chromosome | Hydatidiform Mole | Prenatal Diagnosis | Neonatal Diagnosis | International Classification of Diseases | Molecular Development - Genetics
Diagnosis Links: Prenatal Diagnosis | Pregnancy Test | Amniocentesis | Chorionic villus sampling | Ultrasound | Alpha-Fetoprotein | Pregnancy-associated plasma protein-A | Fetal Blood Sampling | Magnetic Resonance Imaging | Computed Tomography | Non-Invasive Prenatal Testing | Fetal Cells in Maternal Blood | Preimplantation Genetic Screening | Comparative Genomic Hybridization | Genome Sequencing | Neonatal Diagnosis | Category:Prenatal Diagnosis | Fetal Surgery | Classification of Diseases | Category:Neonatal Diagnosis

Terms

Neural Terms  
Neural Development
  • 3DMRI - Three-dimensional magnetic resonance imaging. A new technique that allows 3D analysis of embryonic structures. (More? Magnetic Resonance Imaging)
  • 3rd ventricle - a fluid-filled space formed from neural tube lumen, located within the diencephalon (from the primary vesicle prosencephalon, forebrain).
  • 4th ventricle - a fluid-filled space formed from neural tube lumen, located within the rhombencephalon (from the primary vesicle, hindbrain).
  • adenohypophysis - (anterior pituitary) = 3 parts pars distalis, pars intermedia, pars tuberalis.
  • alar plate - afferent, dorsal horns
  • anlage - (German = primordium, structure or cells which will form a future structure.
  • arachnoid - (G.) spider web-like used in reference to the middle layer of the brain meninges, the arachnoid mater.
  • astrocytes - cells named by their "star-like" branching appearance, are the most abundant glial cells in the brain, important for the blood-brain barrier.
  • basal ganglia - (basal nuclei) neural structure derived from the secondary vesicle telencephalon (endbrain) structure from the earlier primary vesicle prosencephalon (forebrain)
  • basal plate - efferent, ventral horns
  • brachial plexus - mixed spinal nerves innervating the upper limb form a complex meshwork (crossing).
  • brain - general term for the central nervous system formed from 3 primary vesicles.
  • buccopharyngeal membrane - (oral membrane) at cranial (mouth) end of gastrointestinal tract (GIT) where surface ectoderm and GIT endoderm meet. (see also cloacal membrane)
  • cauda equina - (horse's tail) caudal extension of the mature spinal cord.
  • central canal - lumen, cavity of neural tube within the spinal cord. Space is continuous with ventricular system of the brain.
  • cerebral aqueduct - ventricular cavity within the mesencephalon.
  • cervical flexure - most caudal brain flexure (of 3) between spinal cord and rhompencephalon.
  • choroid plexus - specialized vascular plexus responsible for secreting ventricular fluid that with further additions becomes cerebrospinal fluid (CSF).
  • cloacal membrane - at caudal (anal) end of gastrointestinal tract (GIT) where surface ectoderm and GIT endoderm meet forms the openings for GIT, urinary, reproductive tracts. (see also buccopharyngeal membrane)
  • cortex - - CNS structure derived from the secondary vesicle telencephalon (endbrain) from the earlier primary vesicle prosencephalon (forebrain).
  • cortical plate - outer neural tube region which post-mitotic neuroblasts migrate too along radial glia to form adult cortical layers.
  • cranial flexure - (=midbrain flexure) most cranial brain flexure (of 3) between mesencephalon and prosencephalon.
  • diencephalon - the caudal portion of forebrain after it divides into 2 parts in the 5 secondary vesicle brain (week 5). (cavity- 3rd ventricle) Forms the thalmus and other nuclei in the adult brain. (sc-My-Met-Mes-Di-Tel)
  • dorsal root ganglia - (spinal ganglia) sensory ganglia derived from the neural crest lying laterally paired and dorsally to the spinal cord (in the embryo found ventral to the spinal cord). Connects centrally with the dorsal horn of the spinal cord.
  • dura mater- "tough" (Latin, mater = mother)
  • ectoderm - the germ layer which form the nervous system from the neural tube and neural crest.
  • ependyma - epithelia of remnant cells after neurons and glia have been generated and left the ventricular zone
  • floorplate - early forming thin region of neural tube closest to the notochord.
  • ganglia - (pl. of ganglion) specialized neural cluster.
  • glia - supporting, non-neuronal cells of the nervous system. Generated from neuroepithelial stem cells in ventricular zone of neural tube. Form astrocytes, oligodendrocytes.
  • grey matter - neural regions containing cell bodies (somas) of neurons. In the brain it is the outer layer, in the spinal cord it is inner layer. (see white matter white matter)
  • growth factor - usually a protein or peptide that will bind a cell membrane receptor and then activates an intracellular signaling pathway. The function of the pathway will be to alter the cell directly or indirectly by changing gene expression. (eg shh)
  • hox - (homeobox) family of transcription factors that bind DNA and activate gene expression. Expression of different Hox genes along neural tube defines rostral-caudal axis and segmental levels.
  • hydrocephalus - abnormality as the result of an imbalance between the rate at which the CSF is being formed and the rate at which the CSF is passing through the arachnoidal villi back into the blood (hydrocephalus rate is a function of the degree of imbalance in these two). Very small imbalance exhibit subtle, if any, symptoms. Large imbalances will have rapidly evolving symptoms of unmistakable import.
  • isthmus- (G. narrow passage)
  • lamina terminalis - anterior region of brain where cranial neuropore closes.
  • lumbar plexus - mixed spinal nerves innervating the lower limb form a complex meshwork (crossing).
  • mantle layer - layer of cells generated by first neuroblasts migrating from the ventricular zone of the neural tube. Layers are rearranged during development of the brain and spinal cord. (Ven-Man-Mar-CP)
  • marginal zone - layer of processes from neuroblasts in mantle layer. (Ven-Man-Mar-CP)
  • mater - (Latin, mater = mother)
  • meninges - mesenchyme surrounding neural tube forms 3 layer (Dura-, pia-, arachnoid- mater) connective tissue sheath of nervous system. (D-P-A-cns)
  • mesencephalon - (midbrain), the middle portion of the 3 primary vesicle brain (week 4). (sc-R-M-P)
  • metencephalon - the cranial portion of hindbrain after it divides into 2 parts in the 5 secondary vesicle brain (week 5). Forms the pons and cerebellum in the adult brain. (sc-My-Met-Mes-Di-Tel)
  • microglia - CNS innate immune cells that have a macrophage function, derive from you sac progenitor cells migrating into the CNS. microglia
  • myelencephalon - the caudal portion of hindbrain after it divides into 2 parts in the 5 secondary vesicle brain (week 5). Forms the medulla in the adult brain. (sc-My-Met-Mes-Di-Tel)
  • neural tube - neural plate region of ectoderm pinched off to form hollow ectodermal tube above notochord in mesoderm.
  • neural tube defect - (NTD) any developmental abnormality that affects neural tube development. Commonly failure of neural tube closure.
  • neuroblast - undifferentiated neuron found in ventricular layer of neural tube.
  • neurohypophysis - (posterior pituitary=pas nervosa)
  • neuromere - term used to describe the segmental region of the neural tube.
  • neuron - The cellur "unit" of the nervous system, transmitting signals between neurons and other cells. The post-mitotic cells generated from neuroepithelial stem cells (neuroblasts) in ventricular zone of neural tube.
  • neuropore - opening at either end of neural tube cranial (rostral, anterior) neuropore closes (day 25) about 2 days before caudal (posterior) that closes at somite level 32 to 34. Neural Tube Defects (NTDs) can be due to failure of these two neuropores to close.
  • notochord - rod of cells lying in mesoderm layer ventral to the neural tube, induces neural tube and secretes sonic hedgehog which "ventralizes" the neural tube.
  • olfactory bulb - (cranial nerve I, CN I) bipolar neurons from nasal epithelium project axons through cribiform palate into olfactory bulb of the brain.
  • optic nerve - (cranial nerve II, CN II) retinal ganglion neurons project from the retina as a tract into the brain (at the level of the diencephalon).
  • optic vesicle - diencephalon outgrowth that forms the primordia of the retina of the eye.
  • otocyst - (otic vesicle) sensory [#placode placode] which sinks into mesoderm to form spherical vesicle (stage 13/14 embryo) that will form components of the inner ear.
  • pars - (L. part of)
  • pharyngeal arches - (branchial arches, Gk. gill) form structures of the head. Six arches form but only 4 form any structures. Each arch has a pouch, membrane and cleft.
  • pharynx - uppermost end of GIT, beginning at the buccopharyngeal membrane and at the level of the pharyngeal arches.
  • pia mater-
  • placode - specialized regions of ectoderm which form components of the sensory apparatus.
  • pontine flexure - middle brain flexure (of 3) between cervical and cranial flexure in opposite direction, also generates thin roof of rhombencephalon and divides it into myelencephalon and metencephalon. ( sc-^V^ )
  • prosencephalon - (forebrain), the most cranial portion of the 3 primary vesicle brain (week 4). (sc-R-M-P)
  • Rathke's pouch - a portion of the roof of the pharynx pushes upward towards the floor of the brain forming the anterior pituirary (adenohypophysis, pars distalis, pars tuberalis pars intermedia). Where it meets a portion of the brain pushing downward forming the posterior pituitary (neurohypophysis, pars nervosa). Rathke's pouch eventually looses its connection with the pharynx. (Martin Heinrich Rathke 1973-1860, embryologist and anatomist)
  • rhombencephalon - (hindbrain), the most caudal portion of the 3 primary vesicle brain (week 4). (sc-R-M-P)
  • rhombic lip - metencephalon posterior part extending from the roof of the fourth ventricle to dorsal neuroepithelial cells that contributes to the cerebellum.
  • roofplate - early forming thin region of neural tube closest to the overlying ectoderm.
  • spinal cord - caudal end of neural tube that does not contribute to brain. Note: the process of secondary neuralation contributes the caudal end of the spinal cord.
  • spinal ganglia - (dorsal root ganglia, drg) sensory ganglia derived from the neural crest lying laterally paired and dorsally to the spinal cord (in the embryo found ventral to the spinal cord). Connects centrally with the dorsal horn of the spinal cord.
  • spinal nerve - mixed nerve (motor and sensory) arising as latera pairs at each vertebral segmental level.
  • sonic hedgehog - (shh) secreted growth factor that binds patched (ptc) receptor on cell membrane. SHH function is different for different tissues in the embryo. In the nervous system, it is secreted by the notochord, ventralizes the neural tube, inducing the floor plate and motor neurons.
  • sulcus - (L. furrow) groove
  • sulcus limitans - longitudinal lateral groove in neural tube approx. midway between roofplate and floorplate. Groove divides alar (dorsal) and basal (ventral) plate regions.
  • sympathetic ganglia-
  • telencephalon - the cranial portion of forebrain after it divides into 2 parts in the 5 secondary vesicle brain (week 5). (cavity- lateral ventricles and some of 3rd ventricle) Forms the cerebral hemispheres in the adult brain. (sc-My-Met-Mes-Di-Tel)
  • thalamus - (G. thalamos= bedchamber) cns nucleus, lateral to 3rd ventricle, paired (pl thalami).
  • thyroid hormone - hormone required for brain development. T3 (3,5,3′-triiodothyronine) binding to nuclear receptors then act as a transcription factor in both neurons and glial cells.
  • transcription factor - a factor (protein or protein with steroid) that binds to DNA to alter gene expression, usually to activate. (eg steroid hormone+receptor, Retinoic acid+Receptor, Hox, Pax, Lim, Nkx-2.2)
  • trigeminal ganglion - (cranial nerve V, CN V) first arch ganglion, very large and has 3 portions.
  • vagal ganglion- (cranial nerve X, CN X) fourth and sixth arch ganglion, innervates the viscera and heart.
  • ventricles - the fluid-filled interconnected cavity system with the brain. Fluid (cerebrospinal fluid, CSF) is generated by the specialized vascular network, the choroid plexus. The ventricles are directly connected to the spinal canal (within the spinal cord).
  • ventricular zone - Neuroepithelial cell layer of neural tube closest to lumen. Neuroepithelial cells generate neurons, glia and ependymal cells. (Ven-Man-Mar-CP)
  • vestibulocochlear nerve - (cranial nerve VIII, CN VIII, also called statoacoustic)
  • white matter - - neural regions containing processes (axons) of neurons. In the brain it is the inner layer, in the spinal cord it is outer layer. (see grey matter)
Other Terms Lists  
Terms Lists: ART | Birth | Bone | Cardiovascular | Cell Division | Gastrointestinal | Genetic | Hearing | Heart | Immune | Integumentary | Neural | Oocyte | Palate | Placenta | Renal | Respiratory | Spermatozoa | Ultrasound | Vision | Historic | Glossary
  1. Perrine Barraud, Anastasia A Seferiadis, Luke D Tyson, Maarten F Zwart, Heather L Szabo-Rogers, Christiana Ruhrberg, Karen J Liu, Clare V H Baker Neural crest origin of olfactory ensheathing glia. Proc. Natl. Acad. Sci. U.S.A.: 2010, 107(49);21040-5 PubMed 21078992
  2. Ashwin Woodhoo, Lukas Sommer Development of the Schwann cell lineage: from the neural crest to the myelinated nerve. Glia: 2008, 56(14);1481-90 PubMed 18803317
  3. Embryonic vertebrate central nervous system: revised terminology. The Boulder Committee. Anat. Rec.: 1970, 166(2);257-61 PubMed 5414696
  4. 4.0 4.1 Hao Huang, Rong Xue, Jiangyang Zhang, Tianbo Ren, Linda J Richards, Paul Yarowsky, Michael I Miller, Susumu Mori Anatomical characterization of human fetal brain development with diffusion tensor magnetic resonance imaging. J. Neurosci.: 2009, 29(13);4263-73 PubMed 19339620 | PMC2721010 | J Neurosci.


BGDsmall.jpg
BGDA: Lecture 1 | Lecture 2 | Practical 3 | Practical 6 | Practical 12 | Lecture Neural | Practical 14 | Histology Support - Female | Male | Tutorial

Glossary Links

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols

Cite this page: Hill, M.A. 2017 Embryology BGDA Lecture - Development of the Nervous System. Retrieved September 22, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/BGDA_Lecture_-_Development_of_the_Nervous_System

What Links Here?
© Dr Mark Hill 2017, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G