MODULE II: development & TNS

Question 1

developmental neurogenisis

Answer 1

the process by which neurons are formed, become specialized, and wire together across synapses during development

Question 2

zygote

Answer 2

from fertilization to 4 days old, any cell can form any type of cell in the adult organism - totipotent

Question 3

blastula or blastocyst

Answer 3

hollow ball of cells forms around 4-5 days - still totipotent

Question 4

gastrula

Answer 4

3 layered ball of cells forms 7-10 days, cells from one layer can only frm certain types of cells

Question 5

3 layers of the gastrula

Answer 5

1. Ectoderm
2. Mesoderm
3. Endoderm

Question 6

Ectoderm

Answer 6

outer layer, forms skin and nervous system

Question 7

Mesoderm

Answer 7

middle layer, forms muscle, blood and bone

Question 8

Endoderm

Answer 8

inner layer, forms internal organs, lungs, liver, intestines, etc.

Question 9

Neural plate

Answer 9

part of the back ectoderm that forms the neural tube and neural crest by folding in on itself

Question 10

Neural tube

Answer 10

hollow tube of cells that eventually forms the spinal cord, and through vesiculation, the brain

Question 11

Neural crest

Answer 11

these cells eventually migrate out and form the peripheral nerves

Question 12

anencephaly

Answer 12

incomplete folding of the neural tube can result in ^^(lack of brain formation)

Question 13

spina bifida

Answer 13

Incomplete cord sealing leads to this ^^

Question 14

6 main processes that form TNS

Answer 14

1. cell proliferation 2. cell migration 3. chemical & morphological differentiation 4. synaptogenesis 5. cell death & synaptic pruning 6. myelination

Question 15

cell proliferation

Answer 15

the formation of two new cells from one cell by a neural stem cell

Question 16

stem cell

Answer 16

a unspecialized cell that can divide and form two other stem cells

Question 17

When does cell proliferation start?

Answer 17

starts shortly after conception and is complete 4-5 months post-conception

Question 18

too much proliferation

Answer 18

Primitive Neuroectodermal Tumors (PNETs)

Question 19

Primitive Neuroectodermal Tumors (PNETs)

Answer 19

• rare tumor found in children
• forms bc rarely neural stem cells may refuse to stop proliferating like normal

Question 20

too little proliferation

Answer 20

Microcephaly

Question 21

Microcephaly

Answer 21

abnormally small brain caused by death of stem cells and/or insufficent proliferation

Question 22

Cell Migration

Answer 22

The movement of cells from one place to another

Question 23

When does cell migration start?

Answer 23

starts around 8-9 weeks post-conception and is complete 2-3 months before birth

Question 24

The two main types of cell migration

Answer 24

1. Tangential
2. Radial

Question 25

Tangential Migration

Answer 25

(moving up/down or around) of neural crest cells to form schwann cells and neurons in peripheral nerves

Question 26

Radial Migration

Answer 26

(moving our from the center) of cerebral cortical neurons to form the layers of the cerebral cortex

Question 27

Lissencephaly

Answer 27

formation of a brain without folds and cortical layers. can be caused by defects in the radial migration of cortical neurons.

Question 28

Differentiation

Answer 28

The process by which unspecialized stem cells take on their final specialized state

Question 29

2 types of differentiation

Answer 29

1. chemical differentiation 2. morphological differentiation

Question 30

Chemical Differentiation

Answer 30

hormones and other chemical signals activate master regulatory genes

Question 31

Master Regulatory Genes

Answer 31

genes that produce a protein that then turns on neuron-specific proteins

Question 32

Morphological Differentiation

Answer 32

Cells taking on their adult form, dentrites and axons begin to form, continues into childhood

Question 33

dendritic spines

Answer 33

small buds of extensions of the dendrite where synapses form

Question 34

growing dendrites

Answer 34

increase in the number length, and branching of dendrites

Question 35

2 factors of extending axons

Answer 35

1. secretion of chemoattractants: from the target cell that guide the axon to them 2. cell adhesion molecules: that then grasp the axon and adhere it to the target cell

Question 36

synaptogenesis

Answer 36

the formation of a functional synapse between an axon from a presynaptic neuron and the dendrite of a postsynaptic neuron

Question 37

when does synaptogenesis start?

Answer 37

starts during late prenatal development and continues throughout childhood

Question 38

neurotrophins

Answer 38

hormone-like chemicals secreted by postsynaptic neurons and glial cells that INHIBIT the cell suicide pathway

Question 39

Myelination

Answer 39

the formation of myelin sheaths around neurons