Development of the Central Nervous System-the spinal cord

Question 1

The nervous system develops from the ___________ (a thickened area of embryonic ectoderm ).

Answer 1

neural plate

Question 2

The neural plate gives rise to the neural ______, ______, _______

Answer 2

folds, tube, crest.

Question 3

The neural plate and neural tube begins formation (Neurulation) during stage __ of development (__
- ____days) in the region of the fourth to sixth pairs of somites.

Answer 3

stage 10, 22-23 days

Question 4

The neural ____ is an elevation of the lateral edge of the neural plate

Answer 4

neural fold

Question 5

The neural ____ is formed from the fusion of the neural fold

Answer 5

neural tube

Question 6

Fusion of the neural folds and formation of the neural tube proceeds in cranial and caudal direct

The cranial opening, closes on approximately the __th day (18 to 20-somite stage) and

the caudal neuropore __ days later.

Answer 6

25th day (18 to 20-somite stage)

2-3 days later.

Question 7

The neural _____ gives rise to the brain and spinal cord

Answer 7

neural tube

Question 8

The cranial 2/3 of the neural plate and tube, represent the future _____

The caudal 1/3 of the neural plate and tube represents the future __________

Answer 8

brain

spinal cord

Question 9

The neural canal (lumen of the neural tube) forms

1. the ____________ of the brain
2. the __________ of the spinal cord and communicates freely with the amniotic cavity

Answer 9

1. ventricular system

2. central canal

Question 10

The neural _______ (lumen of the neural tube) forms

1. the ventricular system of the brain
2. the central canal of the spinal cord and communicates freely with the amniotic cavity

Answer 10

neural canal

Question 11

_________ is the most severe type of spina bifida

In these cases, the spinal cord in the affected area is open because the neural folds failed to fuse

Answer 11

Myeloschisis

Question 12

What is Myeloschisis?

Answer 12

s the most severe type of spina bifida

In these cases, the spinal cord in the affected area is open because the neural folds failed to fuse

Question 13

___________ defect in the vertebral arch as a result of failure of the embryonic halves of the arch to grow normally and fuse in the median plane

Answer 13

Spina bifida occulta

Question 14

What is Spina bifida occulta ?

Answer 14

defect in the vertebral arch as a result of failure of the embryonic halves of the arch to grow normally and fuse in the median plane

Question 15

_____________ Occurs as a result of abnormal closure of the neural fold in the 3rd and 4th weeks of development.

It may involve the meninges, vertebrae, muscles and skin.

Answer 15

spina bifida or Neural tube defects

Question 16

What is spina bifida or Neural tube defects

Answer 16

Occurs as a result of abnormal closure of the neural fold in the 3rd and 4th weeks of development.

It may involve the meninges, vertebrae, muscles and skin.

Question 17

The dura mater and arachnoid mater usually end at ___ vertebra in adults

Answer 17

S2 vertebra

Question 18

When cerebrospinal fluid is tapped during a lumbar puncture, the needle is inserted at the lower lumbar level (____-___), avoiding the lower end of the cord.

Answer 18

(L4–L5)

Question 19

For a 6-month-old fetus, the spinal cord lies at the level of the __

Answer 19

S1

Question 20

For a newborn the spinal cord terminates at the level of the __ or __

Answer 20

L2 or L3

Question 21

The spinal cord in the embryo extends the entire length of the _______ canal .

Answer 21

vertebral canal .

Question 22

____________ Also known as the ependymal layer

composed of a thick, pseudostratified, columnar neuroepithelium

gives rise to all neurons and macroglial cells (astrocytes and oligodendrocytes) in the spinal cord

Answer 22

Ventricular zone

Question 23

__________ zone gives rise to all neurons and macroglial cells (astrocytes and oligodendrocytes) in the spinal cord

Answer 23

Ventricular zone

Question 24

__________ layer is the intermediate zone between the ventricular and marginal zones

Answer 24

Mantle layer

Question 25

The _______ layer forms the grey matter of the spinal cord.

Answer 25

mantle

Question 26

_________ become neurons as they develop cytoplasmic processes

Answer 26

Neuroblasts

Question 27

_________ layer gradually becomes the white matter of the spinal cord as axons grow into it from nerve cell bodies in the spinal cord, spinal ganglia, and brain.

Answer 27

Marginal layer

Question 28

____ plates contains ventral and lateral motor grey horn cells and column and forms the motor areas of the spinal cord plates contains ventral and lateral motor grey horn cells and column and forms the motor areas of the spinal cord

Answer 28

Basal

Question 29

The alar plates forms the sensory areas

Answer 29

alar

Question 30

______________ (a longitudinal line) separates the two plates (Basal and Alar plate)

Answer 30

Sulcus limitans

Question 31

__________ (dorsal root ganglia) are unipolar and derived from neural crest cells

Answer 31

Spinal ganglia

Question 32

By _ th week, motor nerves appear in the basal plates (ventral horns) of the spinal cord
They collect into bundles to form the ventral nerve roots

Answer 32

4th

Question 33

Fibres originating from cells in dorsal root ganglia (spinal ganglia) form the ______ nerve roots

Answer 33

dorsal nerve roots