LECTURE 3: embryology Flashcards
when is the PRE-EMBRYONIC STAGE
0-14 days
what are the 2 cell layers within the embryonic disk
ectoderm and endoderm
when is the EMBRYONIC STAGE
15 days - 8 weeks
where does the nervous system develop?
ectoderm
when is the FETAL STAGE
end of 8 weeks to birth
when does myelination start
after 8 weeks
when does the neural tube develop
days 18 to 26
where does the Neural plate forms longitudinally from
ectoderm
what makes the neural groove
edges of plate folds
when does the neural groove fold together and what does it form
day 21 and forms the neural tude
where does the neural tube close first
cervical region
the tubes Quickly fuses together rostrally/caudally with
open ends called
neuropores
where does the neural crest move
inside embryo
what cover the tube/crest
ectoderm
the superior neurpore closes when
day 27
the inferior neuropore closes when
day 30
Inner and outer cell layers are formed by the neural tube by day
26
where do the cell bodies become gray matter
inner layer
how does the tubes separate in the inner layer
dorsal/ventral sections
what is the ventral horn responsible for
motor
what is the dorsal horn responsible for
sensory
what does the outer layer of the neural tube do
processes cell bodies
what becomes white matter with axons and glial cells
the outer layer
what does the neural crest cells form
Peripheral sensory neurons
automatic neutrons
endocrine organs
Cells extend 2 processes, 1 to SC and 1 to dermal part of somite forming
dermatomes
Cell bodies of peripheral sensory neurons are ______ SC and in the _______
outside
dorsal root ganglion
the anteromedial part of the somite goes wheree
vertebrae and skull
the posteromediaial somite goes where
muscles of myotome
the lateral somite goes where
dermatome becomes dermis
what is the end of the SC
conus medullaris
what is the nerve roots coming off the end of the SC
cauda equine
Connection of pia, arachnoid, dura mater from end of SC to coccyx is
filum terminale
when does the SC stop growing
4-5 years old
when does the Vertebral column stops growing
16-18 yrs
when does the brain region start to develop
after the closure of superior neurpore
what is in the hindbrain
medulla , pons , cerebellum , with central canal
forming 4th ventricle
in the hindbrain the inner layer cell bodies migrate through what
white matter to go to gray matter
where does Central canal form the cerebral aqueduct connecting 3rd
and 4th ventricles
midbrain
where does the Posterior region remains near midline forming diencephalon to include thalamus, hypothalamus
forebrain
where does the Anterior form telencephalon to become cerebral hemispheres
forebrain
what does the cerebral hemispheres include
basal ganglia , white matter and cortex
what forms B LATERAL VENTRICLES
central canal of the neural tube
T/F : Lateral hemispheric areas do not grow as much as others
T
what does the edges of the lateral sulcus cover
insula
what is considered the 5th lobe
insular
how do neurons travel to final destinations
sending an extension to brain surface and then pulling self along the extensions or by climbing along glial cells
when do neurons differentiate into special functions
after reaching destination
the function of the neurons depends on what
where it lands
when do synaptic vesicles form, microtubules extend beyond growth cone to presynaptic membrane.
when growth cones contact their target cells
when do the neighboring post-synaptic membrane creates receptor sites
as neurotransmitters are released
what is likely to happen due to failed connections or too inactive
neuronal death
how many neurons may go to a single muscle cell during development?
how many neurons may go to a single adult muscle cell?
serveral
only one
what do neuron connections also do
shape development of muscles
muscle fiber type is dependent on the type of
innervation
Myelination of long axons begins in______ with most finished at ____, depending on system
4th fetal month
3 yrs
when are motor roots of the SC myelinated a
1 month
when are nerves from the cortex to motor neurons myelinated
2 years
can a child grow into defects
yes
• Asymmetric tonic neck reflex
• Symmetric tonic neck reflex
• Tonic labyrinthine reflex
are examples of what
Abnormal neck and vestibular reflexes
• Anencephaly
• Arnold Chiari malformation
• Spina bifida
what examples of what
neural tube defects
what happens when abnormal events occur prior to 20 weeks of gestation
major deformities of nervous stem will be present
what is a big risk factor for lots of neurodegenerative conditions
age
what cognitive abilities seem to be preserved with an aging brain
vocab and comprehension
T/F : Normal age-related cognitive changes don’t markedly hinder quality of life
true
what includes memory loss with/without other cognitive involvement
mild cognitive involvement
if someone has MCI they are 90% to develope what
alzheimer’s disease within 5 year s
