2) Development of the Nervous System

Question 1

When is the nervous system most susceptible to insult?

Answer 1

Pre-natal development

Question 2

Where does the fusion of the neural tube begin?

Answer 2

Future cervical region and proceeds in both cranial and caudal directions

Question 3

What are the last parts of the neural tube to close?

Answer 3

Anterior (day 25) and posterior (day 28) neuropores

Question 4

What is anencephaly?

Answer 4

Cranial neural tube defect leading to absence of cranial structures, including the brain

Question 5

What is is rachischisis?

Answer 5

Failure of neural fold elevation so no neural tube

Question 6

Give an example of a caudal neural tube defect:

Answer 6

Spina bifida

Question 7

Where does spina bifida occur must often?

Answer 7

Lumbosacral region

Question 8

Why do neurological deficits occur in spina bifida?

Answer 8

Impairments of normal development of spinal cord and nerves

Question 9

How can neural tube defects be diagnosed?

Answer 9

Raised maternal serum alpha-fetoprotein (open defect)

USS

Question 10

Hoe can neural tube defects be prevented?

Answer 10

Folic acid pre-conceptually (3 months) and for first trimester

Question 11

What condition almost always occurs with spina bifida?

Answer 11

Hydrocephalus which can lead to cognitive delay

Question 12

What is the cauda equina and its relevance to lumbar puncture?

Answer 12

Bundle of spinal roots and nerves at L2/3

Do lumbar puncture at L3/4 or L4/5 after spinal cord has terminated

Question 13

What are the 3 primary brain vesicles?

Answer 13

Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)

Question 14

What are the 5 secondary brain vesicles (and their derivatives)?

Answer 14

Telencephalon and diencephalon (from forebrain)
Mesencephalon (midbrain)
Metencepahlon and myelencephalon (hindbrain)

Question 15

What is the mature derivative of the diencephalon?

Answer 15

Thalamus

Question 16

What is the mature derivative of the mesencephalon?

Answer 16

Midbrain

Question 17

What are the mature derivatives of the metencepahlon?

Answer 17

Pons and cerebellum

Question 18

What is the mature derivative of the myelencephalon?

Answer 18

Medulla oblongata

Question 19

What are the two flexures and where do they form?

Answer 19

Cervical flexure - spinal cord-hindbrain junction

Cepahlic flexure - midbrain

Question 20

How does the ventricular system form?

Answer 20

Tubular structure of neural tube persists to form interconnected reservoirs

Question 21

How can hydrocephalus be treated?

Answer 21

Shunting CSF into jugular venous system or peritoneum

Question 22

What is the function of the roof and floor plates in the neural tube?

Answer 22

Regulate dorsal-ventral patterning

Question 23

Describe the roof plate of the neural tube:

Answer 23

Alar plate and is sensory

Question 24

Describe the floor plate of the neural tube:

Answer 24

Basal plate and is motor

Question 25

Where do the neural crest cells originate from and travel to?

Answer 25

Lateral border of the neuroectoderm tube and become displaced and enter mesoderm

Question 26

What are some nervous system neural crest cell derivatives?

Answer 26

Cranial nerve ganglia, dorsal root ganglia, symp and parasymp ganglia, Schwann cells, leptomeninges

Question 27

What are some head and neck neural crest cell derivatives?

Answer 27

CT and bones of skull and face, odontoblasts, dermis, C cells of thyroid

Question 28

What are some other neural crest cell derivatives?

Answer 28

Melanocytes and adrenal medulla

Question 29

How can defects of migration affect neural crest cells?

Answer 29

Can affect single component or multiple

Vulnerable to environmental insult (alcohol) and genetic

Question 30

Give an example of a condition caused by defects of neural crest migration affecting one structure:

Answer 30

Hirschsprung’s disease - aganglionic megacolon

Question 31

Give an example of a condition caused by defects of neural crest migration affecting multiple structures:

Answer 31

DiGeorge syndrome