THE CENTRAL NERVOUS SYSTEM

EMBRYOLOGY:

On which day of intra-uterie life does this process take place? What is the significance of this process?

This picture shows the process of neurulation

This diagram shows the process of neurulation

This is a scanning electron micrograph showing the primordium of the central nervous system

Which three layers form as a result of this proliferation? Which structures do each of these layers form?

This photomicrograph shows the proliferation of germinal cells of the neural tube

From which layer(s) do the alar and basal plates arise from? What are the functions of the roof and floor plates?

This picture shows the formation of the basal and alar plates

Identify the abnormalities depicted on the pictures. What are the causes of these abnormalities? How are these abnormalities classified?

Identify the abnormalities depicted on the pictures. What are the causes of these abnormalities? How are these abnormalities classified?

Identify this level.

This picture shows the level at which spina bifida occurs

Identify this abnormality Give reasons for your identification?

Identify this abnormality. How did you identify this abnormality?

Identify the three flexures (folds) found in the primitive brain.

How does the pallium and the colliculus ganglionaris form? Which fibres divide the colliculus? Which nuclei are formed as a result of this division?

From which layer(s) of the neural tube does the cerebral cortex develop? In the spinal cord, the white matter is the external layer, whereas in the

developing brain this layer is found in the middle. Account for the differences in position of this layer.

Identify this abnormality. What is the possible cause of this abnormality?

Identify this abnormality What is the possible cause of this abnormality?

Short essay questions Describe the process of neurulation. (8 marks) Describe the embryonic development of the primitive brain. (8 marks) Describe the embryonic development of the spinal cord. (8 marks)

Multiple choice questions The primary brain vesicles include the following structures

a) Telencephalon. b) Prosencephalon. c) Rhombencephalon. d) Metencephalon. e) Diencephalon.

The crebral aqueduct is formed by the cavity within

a) The diencephalon. b) Lateral ventricles. c) Mesencephalon. d) Telencephalon medium. e) Telencephalic vesicles.