06a CNS Development

Question 1

Neural-inducing factors are secreted by (X) and act to signal differentiation of (Y) into (Z).

Answer 1

X = notochord and surrounding paraxial mesoderm
Y = overlying ectoderm 
Z = neural plate

Question 2

The entire CNS arises from:

Answer 2

Neuroectoderm (ectoderm of neural plate)

Question 3

Neurulation is the process by which:

Answer 3

Neural plate forms neural tube

Question 4

What are the openings on either end of neural tube referred to?

Answer 4

Rostral and caudal neuropores

Question 5

Lumen of neural tube becomes (X) in adult.

Answer 5

X = ventricular system (brain) and central canal (SC), filled with CSF

Question 6

In SC development, the neural tube is initially comprised of (X) cells that are (Y) layers thick.

Answer 6

X = germinal neuroepithelial
Y = one

Question 7

In SC development, as (X) cells migrate to form second layer, the first layer of (Y) is renamed “ventricular zone” and later becomes (Z) layer.

Answer 7

X = neuroblasts
Y = germinal neuroepithelium
Z = ependymal

Question 8

In SC development, once (X) cells migrate to form second layer, thickening and differentiation take place and layer becomes referred to as (Y).

Answer 8

X = neuroblasts 
Y = mantle (intermediate zone)

Question 9

In SC development, the outermost layer, (X), is formed from:

Answer 9

X = marginal zone

Axonal processes from mantle (intermediate) zone

Question 10

(X) demarcates the alar (sensory/motor) and basal (sensory/motor) plates.

Answer 10

X = sulcus limitans

Sensory; motor

Question 11

(Visceral/somatic) (motor/sensory) nuclei are located adjacent to midline axis in SC.

Answer 11

Visceral sensory and motor

Question 12

(Visceral/somatic) (motor/sensory) nuclei are located toward lateral edges of grey matter in SC.

Answer 12

Somatic motor and sensory

Question 13

Intraembryonic (X) tissue forms somites. Each somite forms its own:

Answer 13

X = paraxial mesoderm

Sclerotome, myotome, dermatome

Question 14

Cranial neural tube forms three primary vesicles. Name them.

Answer 14

Prosencephalon, mesencephalon, rhombencephalon

Question 15

Primary vesicles of neural tube further subdivide to form five secondary vesicles. List them and the respective primary vesicles each arose from.

Answer 15

1. Telencephalon (pros)
2. Diencephalon (pros)
3. Mesencephalon (mes)
4. Metencephalon (rhomb)
5. Myelencephalon (rhomb)

Question 16

List the flexures that the neural tube undergoes. Indicate if it’s a flexure on dorsal or ventral surface. Star the ones that persist.

Answer 16

1. Mesencephalic (ventral)*
2. Cervical (ventral)
3. Pontine (dorsal)

Question 17

Basic organization of brainstem nuclei along ventricular floor (from medial to lateral)

Answer 17

1. Somatic motor
2. Branchial motor
3. Visceral motor
4. Visceral sensory
5. Somatic sensory
6. Special sensory

Question 18

T/F: not all types of brainstem nuclei are found at each brainstem level.

Answer 18

True

Question 19

Cerebellum cortex formed during development by migration of (X) from (Y) layer.

Answer 19

X = neuroblasts
Y = mantle zone

Question 20

The diencephalon is developed/comprised entirely of (X) cells that form three swellings. List them (ventral to dorsal)

Answer 20

X = alar plate neuroblasts

1. Thalamus
2. Hypothalamus
3. Epithalamus

Question 21

The telencephalon is developed/formed entirely from (X) cells.

Answer 21

X = alar plate neuroblast

Question 22

Disproportionate growth between (X) poles of cerebral hemisphere cause them to appear rotated about central axis, called (Y).

Answer 22

X = frontal and temporal
Y = insular cortex

Question 23

The (X) is an important midline membrane that separates (Y) secondary vesicles during brain development. During cerebral rotation, this structure is used as bridge by (Z).

Answer 23

X = lamina terminalis
Y = telecephalic
Z = commissures (fibers that travel between cerebral hemispheres)