Neuroscience Flashcards
(26 cards)
What are the 2 levels of neural development?
- The systems level
2. The cellular level
What is the systems level?
looking at the changes in size and shape that occur during embryonic development of the NS- Morphogenesis.
what is the cellular level?
‘differentiation’ of the cells from their progenitors to mature neurones
what happens at day 0 of fertilisation?
development begins with the fertilisation of the day- which cleaves to give rise to blastocyst.
when does implantation of the embryo on the uterine wall occur?
implantation of the embryo onto the uterine wall happens at the end of the first week (7th day)
what happens when the embryo has been implanted into the uterine wall?
further development occurs and gives rise to 2 disc embryonic disc: epiblast and hypoblast
what happens at the end of the second week (14 days)?
Process of gastrulation transforms the disc into 3 layered structure with the ‘germ’ layers.
what are the 3 germ layers? and what do they give rise to?
- ectoderm
- mesoderm
- endoderm
they give rise to the tissues of the body
what happens at the end of the 3rd week? (day 21)
by the end of the third week- process of neuralation begins.
what is neuralation?
Neuralation is the creation of the embryonic nervous system from the ectoderm.
what happens in weeks 4-5?
in weeks 4-5 - the embryo is recognisable with a head, tail and some embryonic structures- such as limb buds which grow into becoming limbs- this is the ‘tail bud’ stage.
what is the embryonic period?
the second month of gestation (weeks 4-8)- embryonic period. organogenesis occur.
what is the foetal period?
from three to 9 months- foetal period.
- maturation of the tissues and organs.
- rapid growth of the body
- cell proliferation- important for the brain
what is neural induction?
further development of the ectoderm which develops under the influence of the underlying mesoderm- neural induction.
what happens in neural induction?
a portion of the ectodermal layer becomes neural tissue- which forms the nervous system.
what happens as the tissue becomes neural?
as the tissue becomes neural- it also undergoes morphogenetic changes in shape to become the neural tube- NEURALATION.
when does early neuralation take place?
early neuralation takes place at week 3 (19 and 20 days)
what does the medial part of the ectoderm give rise to?
the medial part of the ectoderm gives rise to the nervous system
what doe the lateral part of the ectoderm give rise to?
the lateral part of the ectoderm give rise to the epidermis of the skin.
what does the medial part of the ectoderm form?
the medial part of the ectoderm forms the neural plate - which begins to thicken at day 19.
what lies beneath the ectoderm?
underneath the ectoderm is the mesoderm- consisting of the the notochord medially and two other blocks of mesoderm.
- underneath this is the endoderm.
what happens to the neural folds between days 19 and 20?
between days 19 and 20, the neural folds rise up on either side of the midline to form a v shape.
what are formed from the mesoderm underneath the neural folds? What does this give rise to?
somites are formed from some of the mesoderm underneath these folds- which later becomes the AXIAL MUSCLES
when does late neuralation take place?
late neuralation takes place between 22 and 23 days.
