Chapter 10- Reporting-Dev Flashcards
Derived from the ectoderm and it is important that it has been called “fourth germ layer”
Neural crest
a population of multipotent progenitor cells
that can produce tissues that emerges from
the dorsal neural tube during early
development.
neural crest
- has the capacity to differentiate into
particular cell types associated with multiple
cell lineages
neural crest
- Neurons; sensory
ganglia, sympathetic
and parasympathetic
ganglia, plexuses - Neurological cells
- Schwann cells
Peripheral Nervous System
- Adrenal medulla
- Calcitonin-secretory cells
- Carotid body type 1 cells
Endocrine and Paraendocrine derivatives
- Epidermal pigment
cells (melanocytes)
pigment cells
- Facial and anterior
ventral skull and
cartilage and bones
facial cartilage and bones
- corneal endothelium and stroma
- Tooth papillae
- Dermis, smooth
muscle, adipose tissue
of skin, head and neck
connective tissue
Process by which
neural crest cells are specified from the
neuroectoderm.
Neural crest induction
thickenings in the surface ectoderm that will
generate the eye lens, inner ear, olfactory
epithelium, and other sensory structures.
placodes
Regionalization of the neural crest
- Trunk Neural Crest Cells
- Cranial Neural Crest Cells
- Cardiac Neural Crest Cells
- Vagal and Sacral Neural Crest Cells
what are the two migratory paths of trunk neural crest?
ventral-lateral migration (early-migrating NCC) and Dorsal-lateral migration (late-migrating NCC)
come around the neural tube and start coming downward through the somite
ventral-lateral migration
around the somite on the outer rim
dorsal-lateral migration
a protein that repels neural
crest cells.
semaphorin-3F
The dorsolateral pathway has already
become specified as _____________ (pigment
cell progenitors) and they are led along the
dorsolateral route by chemotactic fctors and
cell matrix glycoproteins.
melanoblasts
- The head is largely the product, and the
evolution of jaws, teeth, and facial cartilage
occurs through changes in the placement of
these cells. - Migrate to produce the craniofacial
mesenchyme and pharyngeal
mesenchyme
cranial neural crest cells
three major streams of the cranial crest cells
- From the midbrain and rhombomeres 1 and
- From rhombomere 4
- From rhombomeres 6-8
- The caudal region of the cranial neural
crest. - Only these particular neural crest cells
generate the endothelium of the aortic arch
arteries and the septum between the aorta and the pulmonary artery
Cardiac neural crest cells
- form the enteric ganglia of the gut tube and control intestinal peristalsis
- ________, once past the somites, enter into the foregut and spread to most of the digestive tube
- _________, colonize the hindgut
vagal neural crest and sacral neural crest
Pathway: migration of crest cells in the gut
tissue»_space; attraction of cells by GDNF»_space;
binding of GDNF to Ret receptor
vagal and sacral neural crest
The process by which enteric neural crest
cells are deposited in the gut has been
called ______________
directional dispersal
who listed the eight stages of neurogenesis?
Goodman and Doe (1993)
what are the eight stages of neurogenesis?
- Induction and patterning of a neuron-forming
(neurogenic) region - Birth and migration of neurons and glia
- Specification of cell fates
- Guidance of axonal growth cones to specific
targets - Formation of synaptic connections
- Binding of trophic factors for survival and
differentiation - Competitive rearrangement of functional
synapses - Continued synaptic plasticity during the
organism’s lifetime
three major systems of axon guidance
motor neurons, commissural neurons, and optic system
whose axons travel from
the spinal cord to a specific muscle
motor neurons
whose axons must
cross the midline plane of the embryo to
innervate targets on the opposite side of the
central nervous system
commissural neurons
where axons originating
in the retina must find their way back into the
brain.
optic system
three steps of axonal specificity
pathways selection, target selection, address selection
The axons travel
along a route that leads to a particular region
of the embryo.
pathways selection
The axons, once they
reach the correct area, recognize and bind to
a set of cells with which they may form
stable connections.
target selection
The initial patterns are
refined such that each axon binds to a
small subset of its possible targets.
address selection
Neurons at the ventrolateral margin of the
vertebrate neural tube become motor
neurons, and one of their first steps toward
maturation involves ______________
target specificity
Motor neurons in similar places have similar targets
● LMC » Limb musculature
● MMC » Axial musculature
● HMC » Intercostal musculature
● PGC » Sympathetic ganglia
The ___________ and ____________, are most
well-known membrane proteins (but not
exclusively) for their role as repellent
guidance cues during the patterning of
axonal anatomy
ephrins and semaphorins
The proteins of the semaphorin-3 family, also
known as ______________, are secreted proteins
and collapse the growth cones of axons
originating in the dorsal root ganglia.
collapsins
- they coordinate right and left motor activities
- their axons begin growing ventrally down the side of the neural tube
- About two-thirds of the way down,
however, the axons change direction and
project through the ventrolateral neuron
area of the neural tube toward the floor
plate. - Two systems involved in attracting the axons
of dorsal commissural neurons to the ventral
midline.
Commissural neurons
is made in and secreted from the floor
plate and is distributed in a concentration
gradient that is high ventrally and low
dorsally
Sonic hedgehog (Shh)
which is identified
by an assay developed to screen for
diffusible molecules that might guide the
axons of commissural neurons
netrin
is made by, and secreted
from, the floor plate cells, whereas netrin-2 is
synthesized in the lower region of the spinal
cord but not in the floor plate.
netrin-1
are needed as a driving
force for a commissural axon to cross the
midline and grow way from it
repulsive cues
One important chemorepulsive group of
molecules is the ____________, which are
expressed and secreted by midline cells
slit proteins
secreted by the glial cells
at the midline of the nerve cord, and it acts to
prevent most axons from crossing the
midline from either side
Slit
are the receptors for
Slit. Expression of these Robo receptors in
the growth cones of path finding neurons
function to interpret
Roundabout (Robo) proteins (Robo1, Robo2, and Robo3)
The trigeminal ganglion has three main divisions.
● Ophthalmic nerve
● Maxillary nerve
● Mandibular nerve
is involved in the
development and growth of tissues throughout the
body
BMP4
Is a protein on the surface of nerve cells
that can bind to BMP4
BMP
This muscle-derived laminin specifically
binds the growth cones of motor neurons
and may act as a “stop signal” for axonal
growth. In at least some neuron-to-neuron
synapses, the synapse is stabilized by ____________.
N-cadherin
During mammalian development, all muscle
cells that have been studied are innervated
by at least ____________
two axons
Is a construct in which neuroanatomists can
process and define individual neurons in the
brain from neighboring neurons using a wide
hue of fluorescent proteins
brainbow
The study of neural pathways is also known
as ___________ by earlier neuroanatomists.
hodology
is a technique used by
researchers to visualize and trace the
connections of neurons in an organism
brainbow
Scientists genetically modify mice by
inserting a specific region of DNA into their
genome. This DNA construct contains four
different genes, each encoding a distinct
fluorescent protein. These genes are flanked by specific DNA sequences called ____________
lox sites
Another gene, ________, is also introduced into
the mice. This gene codes for an enzyme
called __________________
Cre, Cre recombinase
this is like a genetic on/off switch
promoter region
The first steps in getting retinal ganglion
cell (RGC) axons to their specific regions of
the optic tectum take place within the _______
(the neural retina of the optic cup).
retina
As the RGCs differentiate, their position in
the inner margin of the retina is determined
by ______________ ____________ (N-cadherin and
retina-specific R- cadherin) in their cell
membranes.
cadherin molecules
are critical to the fasciculation of the migrating
axons.
NCAM and L1 cell adhesion molecules
In non-mammalian vertebrates, the final
destination for RGC axons is a portion of the
brain called the ___________________, while
mammalian RGC axons also go to the lateral
geniculate nuclei. At many points, the
journey of RGC axons within the brain
occurs on an astroglial substrate
optic tectum
It appears to be the major mediator of RGC
guidance at the chiasm
Robo2
investigates how the nervous system forms and evolves from embryonic stages through adulthood.
Developmental neurobiology
The path that a neural crest cell takes
depends on the ___________ ______________ it
meets.
extracellular matrix
It can grow and connect to their
targets by following gradients of a protein.
neurons
are proteins that are made
by the target tissue and that stimulate the
particular set of axons able to innervate it.
neurotrophins
It is a process
where an active neuron can suppress
synapse formation by other neurons on the
same target
activity- dependent selection
