Lecture 01 Flashcards
How does a cell develop into an embryonic cell
single cell –> morula –> blastula –> blastocyst –> embryonic disk
( with ectoderm and endoderm)
what does the endoderm turn into
viscera
what does the mesoderm become
bones and muscle
what does the ectoderm become
nervous system and skin
what is anencephaly
neural tube doesn’t form properly, brain doesn’t form properly
infant doesn’t usually survive
what is spina bifida
caudal end of spine does close properly
infant can survive depending on severity
what is induction
when structure produce signals that induce cells to
a. differentiate into different classes of neurons
b. form different anatomical structures
what are the 3 primary brain vesicles
prosencephalon
mesencephalon
rhombencephalon
what is the importance of the primitive streak
creates rostro/caudal symmetry
what does the midbrain differentiate into?
tectum (roof)
tegmentum (floor)
cerebral acqueduct
What orientation does the tectum have (ventral v. dorsal)
dorsal
what orientation does the tegmentum have (ventral v. dorsal)
ventral
what orientation does the cerebral aqueduct have (rostral v caudal)
rostrally
connects rostrally with 3rd ventricle of diencephalon
what is the fn of the tectum
head orienting movement based on auditory or visual cues
what system is the superior colliculi part of
visual
what system in the inferior colliculi part of
auditory
what is the fn of the tegmentum
involved in CONTROL of voluntary movements
what does the rhombencephalon differentiate into
metencephalon
mylencephalon
What is the orientation of the metenceph.
rostral
what is the orientation of the mylenceph
caudal
what does metenceph differentiate into
cerebellum
pons
what does mylenceph differentiate into
medulla
The rhombic lip is which wall (a) of which part of the rhombencephalon (b)
a) dorsolateral
b) metencephalon
the rhombic lip forms?
cerebellum
which wall forms the pons (a) and which part of the brain (b)
a) ventral
b) metencephalon (which is a differentiation of the rhombencephalon)
which walls form the medulla (a), which part of the rhombencephalon form the medulla (b)
a) ventral and lateral
b) mylencephalon
what type of matter are the medullary pyramids composed of
white matter
what do the medullary pyramids contribute to (which tract?)
cortico-spinal tract
which surface are the medullary pyramids on (ventral v dorsal)
ventral surface
Can you list four functions of the cerebellum?
fine movements
posture
equilibrium
motor learning
how do the spinal cord, pons, and cerebellum all work together?
spinal cord sends proprioceptive info which passes through pons
pons gets info form cortex which specify the goals of the movement
cerebellum helps coordinate those movements
how are the cerebral cortex axons and the pontine axons related?
cerebral cortex axons synapse with pontine axons which transfer info to the opposite side of the brain
what is the location where the medulla and spinal cord cross called?
pyramidal decussation
what part of the brain is the pyramidal decussation located in
myelencephalon
which sensory systems make connections in the medulla
sensory (cuneate and gracile nuclei)
auditory (cochlear muscle)
tase (gustatory muscle)
what type of neurons (motor v sensory ) descend from the lateral column- sensory or motor?
motor
what types of neurons (motor v sensory ) descend from ventral column?
motor for axial skeleton
what types of neurons ascend from ventral column
pain
what type of neurons are found in the dorsal column and root?
sensory
what type of neuron is found in the ventral column and root?
motor
what type of neurons are found in lateral horn
preganglionic sympathetic neurons
in dorsal column, (a) sensory info travels (b-up or down) toward brain
a) somatic
b) up
Six stages of wiring the brain
- cell proliferation
- cell differentiation
- cell migration
- axonal path-finding
- connectivity
- maturation
between what two brain structures is the lateral ventricle located
above- cortex
below- basal telencephalon
between what two brain structures is 3rd ventricle the located
above- thalamus
below- hypothalamus
between what two brain structures is the cerebral aqueduct located
above- tectum
below- tegmentum
between what two brain structures is the 4th ventricle located
above- cerebellum
below-pons+ medulla
what types of divisions can happen in cell proliferation
symmetrical
asymmetrical
what is the end result of a symmetrical division
two neuroblasts
what is the end result of an asymmetrical division
one neuroblast
one progenitor cell
what is special about progenitor cells
they can make a lot of stem cells
Is the alar plate sensory or motor?
sensory
is the basal plate sensory or motor
motor
what does the ependymal layer produce (a)
what type of cells are found here (b)
a) CSF
b) neural stem cells
in which layer do cell bodies of developing neurons develop
intermediate or mantle layer
the (a) layer is involved in the process of developing neurons
marginal
which layer is responsible for separating the motor from the sensory sides
sulcus limitans
what is formed in the sulcus limitans? (and close by it, what system is formed?)
sensory + visceral system
somatic system
the specialized tip of growing neurons is called?
growth cones
what does the growth cone connect to in the extracellular matrix?
laminins and fibronectin
the growth cone connects to fibronectin and laminin via?
integrin
what does the growth cone use to bind to other neuronal elements
cadherins and CAMs
what is the projection of the growth cone that decides the direction of the neuron
lamellipoda
the tiny finger-line projections that form on the growth cones that explore the area and then disappear are called?
filopodia
what are the two categories of informational molecules
- fixed signals
2. diffusable signals
what do fixed signals do
they create molecular highways
what are the two types of fixed signals
extracellular fixed signals
cell surface fixed signals
what fn do diffisable signals serve
help with axon guidance
which two adhesive molecules are found extracellularly
laminins
fibronectin
which two adhesion molecules are used for cell surface fixed signaling
CAMs
cadherins
(a) are calcium dependent
CAMS or cadherins
cadherins
CAMS are not Ca2+ dependent. How do they act on growth cones?
via kinases
the mechanism which causes axons to stick together
fasciculation
what is the function of diffusible signals
create chemical gradients to repel or attract axons
what two factors are used to create chemical gradients for the axons
tropic factor
trophic factors
what is the fn of tropins
attract growing axons
what is the fn of troPHins
support survival and growth of axons
I.O.W: life-sustainig factors
what is netrin
chemo-attractant
where is netrin found
very dense in the midline
what role does netrin play with the growth cone
The growth cone has receptors for netrin. The growth cone searches for netrin. Netrin is highly concentrated in the midline. The growth cone, searching for netrin, moves towards the midline
where is slit found
midline
what is the fn of slit
chemorepellant
what receptors does the growth cone have that allow it to bind with slit
robo
what happens to the growth cone when it approaches slit
it gets repelled away from midline. axon leaves spinal cord and starts heading towards the brain
fn of ephrins
repellant signal for temporal (posterior) retinal axons
how does the [ ] of ephrins relate to it repelling ability
high [ ] in posterior tectum
low [ ] in anterior tectum
THUS
temporal (posterior) retinal axons repelled form posterior tectum but NOT form anterior tectum
what is the synaptic cell adhesion molecule
SynCAM
role of neurexin
helps vesicle binds to membrane right before synaptic gap so NT can be expelled into post synaptic cleft
neurolignin
brings many receptors to membrane of post synapse so receptors can attach to contents expelled from presynapse
If a motor neuron is activated it will ALWAYS cause the muscle to contract. T/F?
true
steps to synapse formation
argin –> MuSk–> rapsyn –> ach receptors–> axon releases neuroregulin –> controls # of ash receptors –> Ca2+ entry into growth cone stimulated –> Ca2+ release in growth cone
- -> stimulate release of NT –> change shape of cytoskeleton of pre synapse to match post synapse
what factor prevents apoptosis? tropin or trophic?
trophic
apoptosis vs necrosis
apoptosis- programmed cell death
necrosis- accidental cell death from injury
what 3 kinds of process in neurons do neurotrophins activate
- neuronal survival/death
- synapse stabilization/elimination
- neurite growth/ retraction
what characteristics that describe a neurotrophin
1) absence of neurotrophin = neuronal death
2) surplus neurons survive in presences on neurotrophins
