Development of CNS

Question 1

Anatomical terminology

Answer 1

Question 2

What is the sagittal plane?

Answer 2

Divides body into right and left half

Question 3

What is the coronal plane?

Answer 3

Divides body into anterior and posterior

Question 4

What does ‘rostral’ mean?

Answer 4

Towards head (nose)

Question 5

What does ‘caudal’ mean?

Answer 5

Anything towards tail (feet)

Question 6

What is the cephalic flexure?

Answer 6

the first flexure or bend that forms between the midbrain and hindbrain (bend in CNS)

Question 7

Different terminology due to bend in CNS

Answer 7

Question 8

Explanation of different terminology due to bend in CNS

Answer 8

Question 9

Why can ‘superior’ also be referred to as ‘dorsal’ regarding the forebrain?

Answer 9

Due to this part arising from the dorsal aspect

Question 10

When referring to the forebrain, what is the ‘superior’ aspect the same as?

Answer 10

The dorsal surface

Question 11

When referring to the forebrain, what is the ‘caudal’ aspect the same as?

Answer 11

The posterior surface

Question 12

When referring to the forebrain, what is the ‘rostral’ aspect the same as?

Answer 12

Anterior surface

Question 13

When referring to the forebrain, what is the ‘ventral’ aspect the same as?

Answer 13

Inferior surface

Question 14

When does the nervous system start to develop?

Answer 14

In the 3rd week of development

Question 15

At the end of week two, what appears as a groove in the epiblast layer of the bilaminar disk?

Answer 15

The primitive streak

Question 16

Cells within the epiblast migrate downward through the primitive streak, giving rise to what three layers?

Answer 16

1. Endoderm
2. Mesoderm
3. Ectoderm

Question 17

What do these 3 germ layers form?

Answer 17

The trilaminar embryonic disk

Question 18

What layer is the nervous system derived from?

Answer 18

The ectoderm (outermost layer)

Question 19

In the third week of development, the notochord appears in the mesoderm. What does the notochord secrete? What is the effect of this?

Answer 19

The notochord secretes growth factors which stimulate the differentiation of the overlying ectoderm into neuroectoderm – forming a thickened structure known as the neural plate.

Question 20

What then happens to the lateral edges of the neural plate?

Answer 20

They rise to form neural folds

Question 21

What happens to the neural folds?

Answer 21

he neural folds move towards each other and meet in the midline, fusing to form the neural tube (precusor to the brain and spinal cord).

Question 22

During fusion of the neural folds, some cells within the folds migrate to form a distinct cell population. What is this called?

Answer 22

Neural crest

Question 23

What does the neural crest give rise to?

Answer 23

They give rise to a diverse cell lineage – including melanocytes, craniofacial cartilage and bone, smooth muscle, peripheral and enteric neurons and glia

Question 24

What is this formation of neural tube known as?

Answer 24

Neurulation

Question 25

When is neurulation achieved by?

Answer 25

End of 4th week of development

Question 26

What is the development of the neural plate (thickening of overlying ectoderm) induced by?

Answer 26

Notochord

Question 27

What is the precursor for the spinal cord and brain (CNS)?

Answer 27

Neural tube (this is a closed structure)

Question 28

At what end does the neural tube begin to bend?

Answer 28

At the rostral end

Question 29

In the fifth week of development, what appears at the cranial end of the neural tube? What will these develop into?

Answer 29

3 swellings/vesicles - will develop into brain

Question 30

What are these 3 vesicles called?

Answer 30

1. Prosencephalon 2. Mesencephalon 3. Rhombencephalon

Question 31

What is the prosencephalon also known as?

Answer 31

Forebrain

Question 32

What is the mesencephalon also known as?

Answer 32

Midbrain

Question 33

What is the rhombencephalon also known as?

Answer 33

Hindbrain

Question 34

What will everything **caudal** to the rhombencephalon become?

Answer 34

The spinal cord

Question 35

Is the neural tube hollow?

Answer 35

Yes (like kitchen roll)

Question 36

What fluid is found inside the neural tube?

Answer 36

Cerebral spinal fluid

Question 37

What do these 3 vesicles then develop into?

Answer 37

5 secondary vesicles

Question 38

What are the 5 secondary vesicles called?

Answer 38

1. Telencephalon 2. Diencephalon 3. Mesencephalon 4. Metencephalon 5. Myelencephalon

Question 39

What secondary vesicles does the prosencephalon give rise to?

Answer 39

1. Telencephalon 2. Diencephalon

Question 40

What does the telencephalon then give rise to in the mature brain?

Answer 40

Cerebral hemispheres

Question 41

What does the diencephalon then give rise to in the mature brain?

Answer 41

Thalamus, hypothalamus, and epithalamus

Question 42

What secondary vesicles does the mesencephalon give rise to?

Answer 42

Continues as the mesencephalon

Question 43

What will the mesencephalon then give rise to in the mature brain?

Answer 43

Midbrain

Question 44

What 2ary vesicles does the rhombencephalon give rise to?

Answer 44

1. Metencephalon 2. Myelencephalon

Question 45

What will the metencephalon give rise to in the mature brain?

Answer 45

Pons and cerebellum

Question 46

What will the myelencephalon give rise to in the mature brain?

Answer 46

Medulla

Question 47

What happens to the lumen of the neural tube after the 5 2ary vesicles?

Answer 47

It **remains** - beginnings of ventricular system and central canal

Question 48

Fill in the blanks

Answer 48

Question 49

What do each of the 5 swellings at the rostral end form?

Answer 49

A subdivision of adult brain

Question 50

The cavity of the neural tube persists in different degrees of expansion throughout the tube: 1. Ventricles 2. Connecting channels 3. Vestigial What are each of these?

Answer 50

1. Ventricles - expanded cavities within the brain 2. Connecting channels - link ventricles 3. Vestigial - central canal of spinal cord

Question 51

What is the central canal of the spinal cord called?

Answer 51

Vestigial

Question 52

How many are the subdivisions of the CNS are there?

Answer 52

7: Hemispheres, diencephalon, midbrain, medulla, pons, cerebellum and spinal cord