CNS Development 2- Development of the Brain

Question 1

Primary brain vesicles

Answer 1

Prosencephalon
Mesencephalon
Rhombencephelon

Question 2

Secondary brain vesicles

Answer 2

Telencephelon
Diencephelon (from prosencephalon)
Mesencephalon (does not divide)
Metencephelon
Myelencephelon (from rhombencephelon)

Question 3

Optic stalks

Answer 3

Divide the prosencephelon into telenchepelon (cranial part) and diencephelon (caudal part)

Question 4

Brain flextures

Answer 4

Cephalic flexture
Pontine flexture
Cervical flexture

Question 5

Cephalic flexture

Answer 5

Develops in 3rd week
Region of mesencephelon
aka mesencephalic flexture

Question 6

Pontine flexture

Answer 6

Develops in 7th week

Divides rhombencephalon into metecephelon and myelencephalon

Question 7

Cervical flexture

Answer 7

Develops in 5th week

Between myelencephalon and the spinal cord

Question 8

Development of telencephelon

Answer 8

During 7th week, the cranial part of the telencephalon gives rise to 2 large diventicular on either side (telencephalic vesicles)
Undistended part known as telencephalic median
The lamina terminalis marks the closure of the anterior neural pore, which induces the formation of the cranial vault of the skull
The telenphalic vesicles form the cerebral hemispheres

Question 9

Development of the ventricular system

Answer 9

The cavities within the telencephalic vesicles are the lateral ventricles
Lateral ventricles in open communication with the telencephalon medium through large openings which will later narrow to form the intraventricular foramina
The cavity with the telencephalon medium and the cavity within the diencephalon coalesce to form the 3rd ventricle

Question 10

Development of the primitive cortex

Answer 10

3 layers of developing neural tube
- Ependymal
- Mantle
- Marginal
Cells will migrate from the mantle layer of each pallium into the marginal layer and there will form a single layer of grey matter which is now the primitive cortex
Eventually the cortex will consist of 6 layers
- Some form from the proliferation of the existing layers
- Some will form from the continuous migration of cells from the mantle layer into the marginal layer