Neuronal Development Flashcards
What things come from the Ectoderm?
Sensory organs
Epidermis
Nervous system
What things come the mesoderm?
dermis muscles skeleton urogenital systems ciculatory system
What things come from the endoderm?
GI system
liver
pancreas
respiratory system
what is the known cause of a defect in closure 1?
folic acid deficiency and metabolic teratogens causing spina bifida
What is the known cause of a defect in closure 2?
maternal hyperthermia
folic acid deficiency
metabolic tetatogens-organics
what does a defect in closure 2 cause?
Anencephaly
what causes a defect in closure 3?
it is usually resistant
no known cause
causes mid facial clefts
what is a known cause of a defect in closure 4?
maternal hypertermia
ask about prior health, hot tubs, and extreme exercise in the first trimester
what is a result of a closure 4 defect?
cephalocele- meningies and brain protrude out
What is a known cause of a defect in closure 5?
valproic acid exposed mothers from seizure medications
results in sacral meningocele
Define Nociception
recognition and signaling of a deleterious stimuli (hot or sharp)
Define Pain
concious awareness of the nociceptive event
varies between individuals
low pain thershold= alot of concious awareness
Define suffering
emotional and behavioral sequlae
define deafferentiation pain
pain due to loss of sensation of an afferent fiber
example-phantom limb pain
hyperalgesia
increased sensitivy to stimulation
what are synchiotrophoblasts?
part of the outer cell mass made of trophoblasts that attach to the endometrial lining by secreting adhesive proteins
what are cytotrophobasts?
part of the outer cell mass that grows into the uterine cavity
what do radial glial cells do?
immature astrocytes important for migrating neuroblasts to where they need to go
-release cytokines to tell them where to go in the cns and pns
when does the dorsal midline ectoderm thicken to form the neural plate ?
by the 3rd week in the embryonic phase
when does the fold touch?
21 days ( 3 weeks post fertilization)
what do the little bumps in the fold represent?
somites that represent dermatomal development of the fetus (muscle, bone and dermis)
derived from the mesoderm
what are the neural crest cells?
the migrate to the side of the fold and will become the PNS
what are the cells in the neural tube?
neuroblasts and glial blasts
when does the superior neuropore close? what happens if there is a nonclosure?
day 27
anacephale
when does the inferiot neuropore close? what happens if there is a nonclosure?
day 30
spinabifida
marginal layer
makes up the fibers of the nerves in the spinal cord
myelin
more peripheral
makes white matter
mantle layer
makes up nerve cell bodies, neural blasts and glial blast
more central
makes grey matter
what do neural crest cells become?
generally the PNS posterior root ganglion sensory CN's autonomic ganglion adrenal medulla melanocytes pancreatic islets
what is colchicine?
drug that blocks microtubules
used for gout- increases uric acid secretion in the kidneys
can cause neural tube defects do not give to women of child bearing age
where does the notochord originate from?
mesodern
what does the notochord do that is significant?
defines the long axis of the spinal cord: sends cytokines form SH system that tell the cells where to go
orients the vertebrae- allows somites to migrate and form vertebral body and arch
releases cell adhesive molecules
what does the notochord become?
nucleus pulposes aka the vertebral disk
what is the alar plate?
more posterior becomes the dorsal horn
sensory
what is the basal plate?
more anterior, becomes the ventral horn
motor
when does myelin begin and finish?
begins in fourth weeks of gestation and finishes at 3 years of age
clinically 2 years old- if a child is not waling by age 2 refer to specialist
cortical spinal tracts myelinate by what age? cortical association fibers?
2
3- these are motor neurons that communicate with other motor neurons: communicate from 1 gyrus in the primary motor cortex (gross motor) to another in the secondary motor cortex (fine movement)- ex playing piano requires both
what is myeloschisis?
no overlapping skin
4-5 segments of the cord is exposed on the surfaces
what is holoprosencephaly?
single large ventricle with fusion of midline structures including thalmi
affected neonates have severe facial defects: cyclopia
what are the causes of holoprosencephaly?
chromosomal defects such as trisomy 13, sporatic, or maternal DM
lissencephaly
no gyral pattern-severe mental retardation
what is the goal for the medications for crps?
prevent sympathetic activation
what medications can you use for crps?
phenoxybenzamine
hydrochloride (alpha 1 blocker to prevent vasoconstriction)
clonidine- alpha 2 agonist- blocks the release of NE on the presynaptic neuron
GABA analogs (neurotin)
NMDA antogonist- block glutamate receptors
Trycyclic antidepressants
what if no medications work for CRPS, what can you do?
nerve block injected into DRG- prevents pain from getting into the cord
A delta fibers
large with a lot of myelin (fast)
located on body surfaces and most dense in the skin
sharp, prickly, and intense pain
5-30 m/sec
C fibers
slow, small diameter and no myelin
located deep in the skin and in all tissues
achy, burning, nagging pain
0.5- 2 m/sec
