Embryonic development of the nervous system W1

Question 1

what is gastrulation and when does it occur

Answer 1

embryo transforms into multidimensional structure, occurs in week 3

Question 2

what occurs in gastrulation

Answer 2

cells secrete different proteins and factors in a concentration gradient
thickened band of cells at tail end - primitive streak
endoderm between bilaminar layers becomes the mesoderm

Question 3

what occurs after gastrulation? what week?

Answer 3

neurulation
week 3

Question 4

what occurs during neurulation

Answer 4

thickens to form neural plate, then forms neural cord. edges elevate and pinch up forming neural groove containing neural crest cells

Question 5

what forms during week 4?

Answer 5

neural tube forms from neural tube bending

Question 6

cranial development in week 4?

Answer 6

3 primary brain vesicles:
-forebrain
-midbrain
-hindbrain

Question 7

cranial development in week 5?

Answer 7

5 secondary brain vesicles:
-telencephalon
-diencephalon
-mesencephalon
-metencephalon
-myelencephalon

Question 8

myelencephalon composed of?

Answer 8

medulla

Question 9

metencephalon composed of?

Answer 9

pons and cerebellum

Question 10

mesencephalon composed of?

Answer 10

midbrain

Question 11

diencephalon composed of?

Answer 11

eye cup, thalamus, hypothalamus, epithalamus

Question 12

telencephalon composed of?

Answer 12

cerebrum

Question 13

when does gyrification occur

Answer 13

between week 10 and 40

Question 14

name for abnormal closure of the neural tube at the spinal region?

Answer 14

spina bifida

Question 15

name for failure of neural tube closure at the cranium?

Answer 15

anencephaly

Question 16

what causes neural tube defects and why

Answer 16

folate deficiency - folate is needed to produce RNA and DNA
maternal hypothermia - impairs division of cells
sodium valproate (anti-epileptic)
teratogens

Question 17

3 types of spina bifida?

Answer 17

spina bifida occulta - mildest and most common
meningocele - sac protruding from spinal column
myelomeningocele - sac containing spinal cord protrudes from spinal column (most serious)

Question 18

what are teratogens?

Answer 18

substances that cause congenital disorders in a developing embryo or fetus

Question 19

what do neuroepithelial cells of the neural tube walls divide and differentiate into

Answer 19

neuroblasts -> neurones
gliablasts -> oligodendrocytes, astrocytes

Question 20

examples of what neural crest cells give rise to?

Answer 20

sensory ganglia and neurones
autonomic neurons
Schwann cells
melanocytes (in skin)
odontoblasts (in teeth)
meninges

Question 21

what is Hirschsprung Disease and how does it occur

Answer 21

congenital megacolon
failure of neural crest to migrate and form parasympathetic structures in the colon

Question 22

what are phaeochromocytomas? what are they a rare cause of?

Answer 22

tumour of the chromaffin cells of the adrenal glands (neural crest origins)
rare cause of adrenergic storm due to overproduction of adrenaline and noradrenaline

Question 23

what type of conditions does failure of neural crest cell migration cause?

Answer 23

autonomic conditions