Embryology 2

Question 1

What are the final closures of the……

Answer 1

anterior and posterior neuropour

Question 2

What are the secondary vesicles of the prosencephalon?

Answer 2

telencephalon

diencephalon

Question 3

What is the secondary vesicle of the mesencephalon?

Answer 3

mesencephalon

Question 4

What are the secondary vesicles of the rhombencephalon?

Answer 4

Metencephalon

Myelencephalon

Question 5

What brain structures does the prosencephalon eventually form?

Answer 5

telencephalon
- cerebrum
Diencephalon
- thalamus, hypothalamus, epithalamus and retina

Question 6

What brain structures does the mesencephalon eventually form?

Answer 6

midbrain

Question 7

What brain structures does the rhombencephalon eventually form?

Answer 7

Metencephalon
- pons, cerebellum
Myelencephalon
- Medulla oblongata

Question 8

What are the three initial brain flexures that occur in the 4th week?

Answer 8

neural tube bends to form:

1) midbrain flexure (between prosencephalon and mesencephalon)
2) Cervical flexure ( bet hind brain and spinal cord)
3) Pontine flexure (within hindbrain)

Question 9

At what period of gestation does do the secondary vesicles develop?

Answer 9

5 weeks

Question 10

How do the ventricles form from the neural tube?

Answer 10

neural canal within neural tube dilate to form ventricles

Question 11

What do prosencephalon dilations create?

Answer 11

lateral and third ventricles

Question 12

From what are the cerebral aqueducts formed?

Answer 12

Mesencephalon (caves inward to form smaller gap)

Question 13

What structures are formed from dilation of rhombencephalon?

Answer 13

fourth ventricle

Question 14

What is the innermost layer of the neural tube called?

Answer 14

Ependymal layer (made of neuroepithelial cells which are stem cells)
- these cells give rise to neuroblasts (neurones) and glioblasts (astrocytes/oligodendrocytes)

Question 15

What are the other layers of the neural tube?

Answer 15

Ependymal layer (innermost)
Mantle Layer
Marginal Layer (outermost)
- ependymal layer differentiates to form other layers

Question 16

What are the plates which make up the mantle layer of the neural tube?

Answer 16

1) Alar plate (dorsal, sensory)

2) Basal plate (ventral, motor)

Question 17

What are the mantle and marginal layers composed of?

Answer 17

mantle - cell bodies of motor neurones

marginal - axons of motor neurones

Question 18

What are the four plates of the neural tube and what parts of the spinal cord do they become?

Answer 18

Roof plate - posterior median septum
Alar plate - dorsal gray columns
Basal plate - ventral gray columns
Floor plate - ventral medial fissure

Question 19

What is Neurogenesis?

Answer 19

Process by which neurones and glia proliferate, migrate and are specified to form mature brain

Question 20

What are the neuroepithelial cells?

Answer 20

Neuroblasts

Glioblasts

Question 21

What is cell layering?

Answer 21

neuroblasts move toward periphery of neural tube following set patterns

Question 22

How do glial cells migrate?

Answer 22

Move along the radial glial cells

Question 23

How do somal bodies migrate?

Answer 23

Translocation is self directed

Question 24

What occurs to neurones after elongation?

Answer 24

Synaptogenesis

• establishment of initial synapses
• which are constantly reconfigured throughout life

Question 25

What is synaptic pruning?

Answer 25

• targeted elimination of functional synapses