Problem 3 Flashcards Preview

Development > Problem 3 > Flashcards

Flashcards in Problem 3 Deck (50)
Loading flashcards...
1

Zygote

Fertilized egg

--> has 46 chromosomes ( 50% from each parent)

(0-14 days)

2

The development of the zygote into an embryo

1. after 12h: cell begins dividing

2. after 3 days: zygote is a small mass of homogeneous cells

3. after 7 days: zygote shows 3 distinct cell layers that are the beginning of all tissues

a) Ectoderm
b) Mesoderm
c) Endoderm

--> as these thicken, they grow into a flat oval plate

4. Neurolation
--> the development of the neural PLATE into neural GROOVE, then neural TUBE

5. Development of an embryo

3

Neural groove

The groove between the neural folds

4

Neural tube

The ridges of the neural groove come together to from the neural tube

--> has subdivisions that correspond to the future:

a) forebrain
b) midbrain
c) hindbrain

5

Embryo

Developing human between the 3. to 8. week after fertilization

--> after this it is referred to as a fetus

6

The 7 stages of the development of the Nervous system

(according to lecture)

1. Neurolation

2. Neurogenesis/Proliferation

3. Cell migration/Aggregation

4. Differentiation

5. Synaptogenesis

6. Synaptic Pruning + Neuronal cell death

7. Synapse rearrangement

(8. Myelination)

7

Neurogenesis/Proliferation

Mitotic division of the cells of the neural tube to provide progeny cells/ neurons

8

Cell migration

The produced cells migrate along the radial glial cells to their appropriate regions

--> ventricular --> intermediate --> marginal region

9

Differentiation

The transformation of these cells into dinsinctive types of neurons + glial cells

10

Synaptogenesis

The establishment of synaptic connections, as axons + dendrites grow

11

Neuronal cell death

Selective death of many nerve cells

12

Synapse rearrangement

Describes the loss of some synapses + the resulting development of others in order to refine synaptic connections

--> Result: ex.: each muscle fiber comes to be innervated by only one motor neuron, not many

--> this is evident in the thinning of grey matter

13

Cell - Cell interaction

The general process during development in which one cell affects the differentiation of the neighboring cells

14

Radial glial cells

Glial cells that extend from the inner to the outer surfaces of the emerging NS

--> serve as "guide" to the newly formed cells

15

Cell adhesion molecules
(CAMs)

Chemicals that promote the adhesion of the migrating cells with the radial glial cells

16

Expression

The process by which the cell makes an mRNA transcript of a particular gene

--> happens when the cell reaches its destination after migrating

--> shapes the cell into the distinctive forms & functions of the neurons found in that particular region

17

What influences differentiation ?

1. Local environment (neighboring cells)

2. Intrinsic self organization

ex.: purkinje cells --> have very specific dendritic branches

18

Notochord

Rodlike structure that releases a protein that diffuses tp the to spinal cord and directs some cells to become motor neurons

19

Induction

The process by which one set of cells influences the fate of neighboring cells by secreting a chemical

20

Regulation

If a cell is injured or lost, other cells will fill in for the missing cells

--> compensation

21

Stem cell

Cell that is undifferentiated and can therefore take on the fate of any cell

22

Growth cones

Growing tip of a dendrite or axon

23

Filopodia

Fine + tubular outgrowths from the growth cone (predendrites)

--> they adhere to CAMs, then contract to pull the growth cone in a particular direction

24

Chemoattractants

Chemical signal that attracts certain growth cones

25

Chemorepellents

Chemicals that repel growth cones

26

Why are chemoattractants + chemorepellents so important ?

Because some axons need to stay on one side of the body and some need to cross over

27

Apoptosis

Naturally occurring cell death

--> interfering with apoptosis may cause the brain to grow too large for the skull

28

Death genes

Genes that are expressed only when a cell undergoes apoptosis

29

How is Apoptosis regulated ?

It is regulated by

a) cell cell interactions

b) availability of synaptic targets




30

What do Neurons compete for ?

a) SYNAPTIC SITES
--> those who make adequate synapses survive, those who don't die

b) NEUROTROPHIC FACTORS
--> chemical that feeds the neurons and thus helps them to survive