Development of the nervous system

Question 1

growth

Answer 1

an increase in the number of cells and enlargement of cells

Question 2

morphogenesis

Answer 2

development of a unique structure (differentiation, proliferation, apoptosis)

Question 3

propagation/proliferation

Answer 3

increase in number of the same cell type

Question 4

differentiation

Answer 4

development of a new (different) cell type

Question 5

apoptosis

Answer 5

programmed cell death

Question 6

week 1 stages

Answer 6

1) fertilization (zygote)
2) cleavage (morula)
3) blastocyst formation (blastocyst)
- epiblast becomes embryo
- hypoblast becomes yolk sac which becomes chorion
4) implantation

Question 7

week 3 - gastrulation

Answer 7

formation of 3 layers as some epiblast cells proliferate and migrate through the primitive streak (PS)
- endoderm
- mesoderm
- ectoderm

Question 8

endoderm

Answer 8

PS epiblast displace the hypoblast cells

Question 9

mesoderm

Answer 9

PS epiblast become mesenchyme (migrating cells) which become mesoblasts

Question 10

ectoderm

Answer 10

remainder of the epiblast cells

Question 11

totipotent cells

Answer 11

can form any cell of the body, only cells undergoing cleavage

Question 12

pluripotent cells

Answer 12

can form any cell of the body except for the placenta

Question 13

notochord

Answer 13

arises from movement of PS cells cranially, defines primordial axis of embryo, basis for axial skeleton development, induces the nervous system to develop

Question 14

neurulation

Answer 14

1) notochord induces thickening of neural plate (previously ectoderm)
2) invagination of neural plate forms neural groove, which has neural folds one ach side
3) neural folds fuse together, forming the neural tube
4) neural crest cells fuse, as do surface ectoderm cells
5) neural crest cells migrate away from neural tube

Question 15

somites

Answer 15

arise from segmentation of the paraxial mesoderm, differentiate into:
- sclerotomes: give rise to vertebreae
- myotomes: gives rise to skeletal muscle of trunk and limbs
- dermatomes: give rise to dermal skin component

Question 16

neural tube structures

Answer 16

neural tube seals, anterior (rostral) and posterior (caudal) neuropores seal last

• rostral = brain
• cavity = ventricular system
• caudal = spinal cord

Question 17

neural crest cells

Answer 17

forms the basis of the cells of the PNS

Question 18

primary vesicles of brain development

Answer 18

1) prosencephalon (forebrain)
2) mesencephalon (midbrain)
3) rhombencephalon (hindbrain)

Question 19

prosencephalon

Answer 19

forebrain
secondary vesicles:
- telencephalon
- diencephalon

Question 20

mesencephalon

Answer 20

midbrain
secondary vesicles:
- mesencephalon

Question 21

rhombencephalon

Answer 21

hindbrain
- metencephalon
- myelencephalon

Question 22

flexures

Answer 22

bends that change the locations of various structures

Question 23

cervical flexure

Answer 23

between rhombencephalon and spinal cord, straightens out

Question 24

cephalic flexure

Answer 24

at the future midbrain, persists as bend between cerebrum and brainstem

Question 25

pontine flexure

Answer 25

dorsal surface of brainstem, neural tube walls spread apart to form diamond-shaped cavity

Question 26

basal plate

Answer 26

formed by anterior portion of neural tube, motor neurons are found here

Question 27

alar plate

Answer 27

formed by posterior portion of neural tube, sensory neurons are found here

Question 28

telencephalon

Answer 28

brain derivatives - cerebral hemispheres ventricle derivatives - lateral ventricles

Question 29

diencephalon

Answer 29

brain derivaties - thalamus, hypothalamus, retina ventricle derivates - third ventricle

Question 30

mesencephalon (secondary)

Answer 30

brain derivative - midbrain ventricle derivative - cerebral aqueduct

Question 31

metencephalon

Answer 31

brain derivative - pons ventricle derivative - part of fourth ventricle

Question 32

myelencephalon

Answer 32

brain derivative - medulla ventricle derivative - part of fourth ventricle

Question 33

spinal cord development - cells and layers

Answer 33

ependymal cells - line future ventricles neuroblasts - become neurons layers: - ependymal layer (ependymal cells) - mantle layer (neurblasts) - marginal layer (processes/future white matter)

Question 34

defects in neural tube closure

Answer 34

exposed CNS from failure of nearby bone development, fatal

Question 35

defects in anterior and posterior neuropore closures

Answer 35

anterior: forebrain and posterior skull defects, usually fatal posterior: spina bifida

Question 36

defects in brain vesicle development

Answer 36

mental deficits

Question 37

development of optic cup

Answer 37

optic pits are a section of neural folds (evagination), optic pits bulge out more and tips come closer, optic pits fuse, invagination forms optic cup

Question 38

development of the retina

Answer 38

inner portion of optic cup becomes neural retina outer portion of optic cup becomes RPE

Question 39

choroidal fissure

Answer 39

where portions of optic cup will meet, fuses trapping hyaloid artery and vein

Question 40

what induces gastrulation?

Answer 40

primitive streak

Question 41

what induces neurulation?

Answer 41

notochord

Question 42

what induces optic vesicles?

Answer 42

surrounding mesochyme

Question 43

what induces lens pit?

Answer 43

optic cup