Blake_Anatomy_10_Development of Neuro System Flashcards
Ectoderm yields:
Epithelium
Nervous tissue
Mesoderm yields:
muscle and connective tissue
from which primary germ layer is epithelium derived?
Ectoderm
Mesoderm
Endothelium
from which primary germ layer is muscle and connective tissue derived?
mesoderm
from which primary germ layer is nervous tissue derived?
ectoderm
Endoderm yields:
epithelium; specifically, the gut tube
Steps in Neurulation (4)
- Neuroectodermal tissue differentiate from the ectoderm and thicken into the neural plate. The neural plate border separated the ectoderm from the neural plate.
- The neural plate bends dorsally, with the two ends eventually joining at the neural plate borders which are now referred to as the neural crest
- The closure of the nural tube disconnects the neural crest from the epidermis. Neural Crest cells differentiate to form most ot the peripheral nervous system
- The notochord degenerates and only persists as the nucleus pulposus of the intervertebral discs. Other mesoderm cells differentiate into the somites, the precursers of the axial skeleton and skeletal muscle
Coronal (dorsal/ventral) divisions of the Early Cord (5)
- Roof plate
- alar plate
- sulcus limitans
- basal plate
- floor plate
What type of tissue comprises the early neural tube?
Pseudostratified columnar (neuro) epithelium
how are the epithelial cells of the early neural tube characterized?
High degree of mitotic activity
What is the result of celular division and maturation of the early nerual tube?
a population of bipotential progenitor cells, which will give rise to either neuronal or glial progenitor cells.
Cell lineages in developing CNS (beginning with bipotential progenitor cell)
Bipotential progenitor cells of the Neural tube:
- Neuronal Lineage Progenitor
- Neurons - transmit electrochemical signals
- Glial Lineage Progenitor
- Neuroglia - Supporting cells of the CNS - Insulate, nourish, suport and protect neurons
Cytodifferentiation
Postmitotic neurons and glioblasts migrate outward to form an ____1___ ______ or _______ _____. This will become the ___2____ ______ ______ that contains neuronal cell bodies and neuroglia.
____3___ ________ (myelinated) move out to surround the developing grey matter and form the outer white matter (also called the____4___ ________).
- Intermediate mantle or cortical zone
- inner grey matter
- Neuronal processes
- marginal zone
Molecular regulation of nerve differentiation in the cross-sectional spinal cord: (4)
- BMP4 and 7 secreted in the ectoderm establish a signaling center in the roof plate
- BMP4 in the roof plate upregulates a cascade of TGF-ß proteins, including BMP5 and 7, activin, and dorsalin
- SHH from the notochord establishes an SHH signaling center in the floor plate
- OVERLAPPING gradient involving the dorsal and ventral factors is established in the neural tube
As the neural tube is differentiating, what is happening to the mesoderm lateral to it?
Mesoderm is divided into different regions on the basis of spatial position with respect to the notochord.