CNS Development

Question 1

What features are considered part of an intra-uterine environment?

Answer 1

• Maternal health and disease
• Insults during pregnancy
• Placental function and fetal nutrition

Question 2

What features are included in the extra uterine environment?

Answer 2

• Nutrition, environmental toxins
• Emotional and social factors (e.g. neglect/lack of stimulation)
• Drug/alcohol exposure

Question 3

What are the four periods of brain development?

Answer 3

The embryonic period (conception to week 9)

Fetal development (week 9 to 40/42)

Post natal development

The adolescent Brain

Question 4

What tissues and structures come from the Ectoderm?

Answer 4

Skin nails hair and neural tissue

Question 5

Muscle, bone, cartilage and the vascular system all originate from what embryonic layer?

Answer 5

Mesoderm

Question 6

The Endoderm forms what structures in the body?

Answer 6

gut and respiratory system

Question 7

What 2 layers arise from the inner cell mass of the embryo?

Answer 7

Epiblast

Hypoblast

Question 8

The epiblast is a primitive form of the ectoderm. TRUE/FALSE?

Answer 8

TRUE

Question 9

The hypoblast is a primitive form of the Mesoderm. TRUE/FALSE?

Answer 9

FALSE

primitive form of the ENDOderm

Question 10

What is the first neural structure to form in the embryo and when does it form?

Answer 10

The neural tube

20-27 days

Question 11

What type of cells form the neural plate?

Answer 11

Neural progenitor cells

Question 12

What does the hollow centre of the neural tube become?

Answer 12

ventricular system and central channel of the spinal cord

Question 13

What does the anterior /rostral tube become?

Answer 13

brain

Question 14

What tube in the embryo forms the spinal cord

Answer 14

Caudal tube

Question 15

How many primary brain vesicles are present in a 3-4 week embryo?

Answer 15

3
Prosencephalon (FOREBRAIN)
Mesencephalon (MIDBRAIN)
Rhombencephalon (HINDBRAIN)

Question 16

How many secondary brain vesicles are present in a 5 week embryo?

Answer 16

5

Question 17

What is the neocortex?

Answer 17

Most recent part of the cerebral cortex responsible for sight and hearing

Question 18

What molecules are involved in signalling in the neocortex?

Answer 18

Emx2 and Pax6

Question 19

What is the name given to the original smooth appearance of the brain?

Answer 19

lissencephalic

Question 20

After how many weeks of foetal development are primary, secondary and tertiary sulci developed in the brain?

Answer 20

Primary Sulci (between weeks 8-26)
Secondary Sulci (week 30-35)
Tertiary Sulci (week 36)

Question 21

Describe assymetrical cell division during the foetal period

Answer 21

Neural progenitor cells divide into one progenior cell and one neuron

Progenitor cells stay in ventricular zone for further division and neurons move out to neocortex

Question 22

What is neuronal migration?

Answer 22

How neurons move from place where they are developed, to their final position in the brain

Question 23

Give examples of methods of neuronal migration

Answer 23

Somal translocation
Radial glial guides
Tangential migration

Question 24

What percentage of neurons will be lost pre-natally?

Answer 24

50%

Question 25

What percentage of neuronal connections will be eliminated throughout life?

Answer 25

50%

Question 26

In what direction does myelination occur?

Answer 26

from bottom to top and from the back to the front of the brain

Question 27

Describe how the brain is reorganised during adolescence

Answer 27

• Many synapses are eliminated
• Increase in white matter volume
• Changes in neurotransmitter systems