Development of the Nervous System Flashcards Preview

2.4.1. Nervous System > Development of the Nervous System > Flashcards

Flashcards in Development of the Nervous System Deck (17):
1

The CNS devel from where?

Neural tube

2

What process produces the notochord?

Gastrulation

3

What does the notochord produce?

Induces neurulation = conversion of overlying ectoderm to neurectoderm

Thickening and elevation of the neural plate = neural tube formation

4

By what day is the NT completely closed?

28-32

Process takes place in 10 days

5

Cranial neuropore closure defect can result in what?

anencephaly

6

Caudal neuropore closure defect can result in what?

Spina bifida

7

Describe spina bifida

Defect in closure of neuropore

Most commonly a defect in caudal (lumbosacral) neural tube to close

Untreated hydrocephalus = cognitive delay

Can contain – CSF, meninges and neural tissue

8

Which neural tube defects are incompatible with life?

Anencephaly = failure of NT closure cranially, absence of cranial structure including brain

Rachischisis = failure of neural fold elevation

9

How are neural tube defect diagnosed?

Raised maternal serum alpha-fetoprotein

USS

10

How can neural tube defects be prevented?

Folic acid

Pre-conceptual and 1st trimester reduces incidence by 70%

11

Briefly how does the nervous system devel from the neural tube?

Neuroectoderm tube has 3 sections
1) lumen forms ventricular system

2) 3 cranial dilations 5 anatomical divisions of the brain

3) caudal tail spinal cord

12

Outline how the spinal cord forms

Most of the length of the neural tubes gives rise to the spinal cord

When the spinal cord is the same length as the vertebral column the spinal roots must elongate – forming cauda equina

13

Outline the development of the brain

During neural fold formation 3 primary brain regions form:

1) forebrain, 2) midbrain, 3) hindbrain

Theses become the primary brain vesicles

At 5 weeks of development five secondary brain vesicles are formed

14

Describe hydrocephalus

Blockage of the ventricular system (tumour, infection)

Obstruct flow = accumulation of CSF

15

What are the flexures of the NT?

Growth and development at cranial NT exceeds available space linearly, it must fold up

Cervical flexure

Cephalic flexure

16

How do the ventricles of the brain form?

Tubular structures of the CNS persist through development

17

What are neural crest cells?

Cells of the lateral border of the neuroectoderm tube

These cells migrate and contribute to a wide range of structures