Neurological Development Two

Question 1

What does gastrulation result in?

Answer 1

The formation of three primary germ layers

Question 2

What are the three primary germ layers?

Answer 2

Endoderm
Mesoderm
Ectoderm

Question 3

What is the definition of gastrulation?

Answer 3

The formation of three primary germ layers and the notochord is developed in this time.

Question 4

What two features of a cell are inversely proportional

Answer 4

The plasticity/capacity for self renewel of a cell diminishes as its function increases.

Question 5

What sort of cells important in growth are highly plastic but not very functional?

Answer 5

Stem cells

Question 6

What does the endoderm give rise to?

Answer 6

Linings of the internal organs, gastrointestinal, respiratory, endocrine

Question 7

What does the mesoderm give rise to?

Answer 7

Muscles and connective tissue

Question 8

What does the ectoderm give rise to?

Answer 8

Brain and skin.

Question 9

Following sex what must occur before a blastocyte can form?

Answer 9

Two germ cells (egg and sperm) must fuse and this results in stem cells, leading to blastocyte and trophoblast formation etc…

Question 10

Whats the first essential step following early blastocyte formation that allows brain formation?

Answer 10

Gastrulation - as ectoderm has formed

Question 11

What are the next four steps following gastrulation?

Answer 11

Induction
Neuralisation
Fusion (end of neuralisation)
Vesicle formation

Question 12

What is induction?

Answer 12

Induction is the development of different tissues and layers because of the influence from other tissues.

pretty much : How different tissue types form

Question 13

What mediates induction?

Answer 13

Growth factors mediate the induction process

Question 14

What are the main growth factors in Brain development?

Answer 14

BMP4 (Bone Morphogenetic Protein 4

Question 15

What is BMP4’s antagonists?

Answer 15

Noggin or Chordin

Question 16

Why does BMP4 have antagonists?

Answer 16

Different concentrations of growth factors (hence antagonists) produce different affects / growth levels on cells)

Question 17

What secretes BMP4?

Answer 17

Notochord

Question 18

What does BMP4 without antagonist do?

Answer 18

Induces ectoderm to become epidermis

Question 19

How does BMP4 induce CNS development?

Answer 19

BMP4 when inhibited slightly by chordin or noggin causes anterior neuroectoderm to form (brain)

Question 20

What induce the spinal cord to form?

Answer 20

BMP4 and fibroblast growth like factor causes posterior neuroectorderm to form

Question 21

At what stage of development does BMP4 take effect?

Answer 21

INduction, during the formation of neural plate

Question 22

What is the process of neuralation?

Answer 22

The formation of the nerual tube

Question 23

What is also an essential factor that influecnes the outcome of induction effects of BMP4?

Answer 23

The time it occurs during the developing fetus

Question 24

What causes the neural tube to form?

Answer 24

The notochords secretion of growth factor?

Question 25

Why does a neural tube form?

Answer 25

THe notochord causes different parts of the neural plate to grow at different rates

Question 26

IN which direction does the neural tube close?

Answer 26

(Rostral) Tail - Head (Caput)

Question 27

While the neural tube is forming, what else is happening in the same region?

Answer 27

A cluster of cells between the brain and skin form - called nueral crest

Question 28

What does nerual crest give rise to?

Answer 28

PNS
Many structures esp of face
- Neurons and glia of face
- Nuerons and glia of PNS of face
- Sensory neurons of face and their glia
- Sympathetic adrenal cells
- CT
- Bone and cartilage

Question 29

What are two possible outcomes of neural tube failure to close?

Answer 29

Anterior neural tube pore = anencephaly

Posterior neural tube pore = spina bifida

Question 30

What would result from a anterior neural tube pore?

Answer 30

Anencephaly = no brain development

Most fetuses undergo spontaneous abortion as do not meet checkpoint standards

Question 31

What would result from posterior neural tube pore?

Answer 31

Spina bifida - Can be detected

Question 32

What are the forms of spina bifida?

Answer 32

Spina bifida Occluta = hidden malclosures in the spinal column asmptomatic and do not pose pathological threat

Spina bifida cystica = external fluid filled sac, contains protruding neurons and CSF

Question 33

Whats significant at four weeks of development?

Answer 33

3 vesicles have formed

Prosencephalon (forebrain)
Mesenscephalon (midbrain)
Rhombancephalon (hindbrain)

Question 34

Between 4-6 weeks what is significant with regards to the vesicles?

Answer 34

Five vesicles have formed

The prosencephalon has given rise to:
Two telencephalon (L and R cerebral hemispheres)
Diancephalon (Thalamus and some hypothalamus)

The mesencephalon still exists as is

The rhombancephalon has given rise to:

Metancephalon which froms the cerebullum
Myeloncephalon which forms the pons and gthe medulla

Question 35

Why does the brain fold during development?

Answer 35

AS different parts grow at different rates (known as flexures)

Question 36

What are some important folds during development?

Answer 36

Midbrain Flexure
Cephalic flexure
Pontine flexure
Cervical Flexure

Question 37

During induction what does the ectoderm closest to the notochord become?

Answer 37

Neuroectoderm

Question 38

Induction gives rise to the?

Answer 38

Neural plate

Question 39

What is the difference between caudal and rostral?

Answer 39

Rostral is towards the front of the brain, while caudal is the back towards the spinal cord i.e posterior and inferiorly.

Question 40

With Neural tube closure, which ends failing to close results in what?

Answer 40

Rostral and caudal malclosure results in anencephaly. As both terms refer to the cerebral cortex.