How to make a brain Flashcards
what is neurulation
forming a tube from a plate
what s the neural plate made from
ectoderm
it is where the neural plate starts
what s the neural plate made from
ectoderm
it is where the neural plate starts
what are the important days in the early development of the cns
plate (columnar epithelium) makes a tube in the end
first plate–> tube
day 19 a midline groove is apparent and neurulation is induced by the notochord
day 20-21 neural groove and fold formed on plate edge
day 21+ neural folds fuse in rostral caudal direction (apical constriction) to create a tube
day 25 rostral neuropore closure
day 27 caudal neuropore closure
what happens if rostral neuropore doesnt close
forebrain doesnt form- anencephaly
what are risk factors for neural tube defects
folate deficiency
diabetes
epilepsy drugs
previous anencephaly
what happens if there are defects at the caudal neuropore
spina bifida
what is the most severe form of spina bifida
myeloschisis
what is myeloschisis
open neuropore, nervous system on surface as a pit
what is meningomyelocele
closed neuropore but defect around spinal cord
defect in vertebrae and meninges are bulging
spinal cord on outside of protection of vertebrae
what is meningocele
meninges bulging
spinal cord still within spinal column
what is spina bifida occulta (1/10 individuals)
when a baby’s backbone (spine) does not fully form during pregnancy.
what are the three swellings of the neural tube
fore, mid, hindbrain
what are the vesicles in the brain
fore, mid, hindbrain vesicles
wha does the space between the vesicles contain
csf, vesicles always connected
what happens to forebrain during development
grows two lateral expansions (like ears), centre becomes diencephalon
what happens to hindbrain during development
develops into brainstem and cerebellum with a central ventricle expanding
what do the lumen of the tubes develop into
forebrain vesicle – two lateral ventricles and third ventricle (with interventricular foramen joining them together)
midbrain– cerebral aqueduct
hindbrain– fourth ventricle
what do the walls of the tube form
forebrain- telencephalon, 2 cerebral hemispheres and diencephalon
midbrain- mesencephalon
hindbrain- metencephalon (pons, cerebellum), myelencephalon (medulla)
where does the cerebral hemispheres derive from
forebrain vesicle
what causes the c shape formation
The hemispheres grow round in a C-shape and then back again, pulling all structures internal to the hemispheres (such as the ventricles) with them.
what is the cephalic flexure
occurs in week 6
s the first flexure or bend, that forms in the region of midbrain
found in mesencephalon
what occurs at 12 weeks
strong temporal lobe growth
devloping insula
what is the insula
grey matter
what covers insula
operculum (lid) of cortex from adjacent lobe
fronto-parietal and temporal operculum
what happens at 16 weeks and later
c shape cerebral hemispheres
lobes and grooves now evident
what happens ar full term
ruffling and convolution
crinkled surface
what are gyri
they are the bumps, increase surface area and volume of grey matter
how do you make the brain have a bigger surface area
sulcus and gyri
name some c shaped structures
hippocampus (memory)
lateral ventricle
fornix
corpus callosum
caudate nucleus (curved shape of basal ganglia) that follows later ventricle
why are there c shaped structures in the brain
due to temproal lobe growth
what is the fornix
connects hippocampus with anterior structures
what is the corpus callosum
connects the two hemispheres together
where is the fornix
above thalamus
what is the internal capsule
and what does it do during development
white matter bundle
divides basal ganglia- lentiform nucleus and caudate nucleus
why can you see two parts of the caudate nucleus in a coronal slice
because it is c shaped, so cut twice
why can you not see the cerebral aqueduct in a coronal slice
2D slice- therefore very rare to see
how does the fourth ventricle form
opening out of neural tube forms roof o fourth ventricle
around week 6
what happens to the grey matter before and after the 4th ventricle forms
Before- sensory grey matter in dorsal position
After- sensory grey matter becomes more lateral , motor is more medial
what does the caudal neural tube become
the spinal cord
what are the layers that start to make the spinal cord
ventricular layer (generating cells to make–>
Mantle layer that becomes grey matter
Marginal layer (outside) all white matter concentrates here
Sensory neurons in dorsal region
what forms the dorsal root
ingrowth of neurites from dorsal root ganglion
what forms ventral root
outgrowth from neurons motor grey
what does bmp stand for
bone morphogenetic protein
what does bmp do
inhibits neural ectoderm, which promotes skin
what induces the neural tube formation
notochord.
produces noggin, chordin, follistatin, which block bmp
therefore allows differentiation of neural ectoderm
what happens to neural crest cells during neurulation
migrate away from neural tube
epithelial mesenchymal transition
spread through embryo and give rise to many different cell types.
name some cells that neural cells form
4 genetic disorders of neural crest
cranial nerve ganglia
autonomic ganglia
craniofacial skeleton
melanocytes (dalmation dogs)- patchy and deaf
schwann cells
adrenal medulla
cartilage
bone
neurons, glia
connective tissue
name some neural crest development defects
waardenburg’s syndrome
treacher collins syndrome
what gene is deleted in waardenburgs syndrome
Pax-3 gene
what protein is defected in treacher collins syndrome
TCOF1 gene
