Basic Neuro Embryology (Based on BRS Embryo)

Question 1

What three sources become the peripheral nervous system?

Answer 1

1. Neural crest cells
2. Neural tube
3. Mesoderm

Question 2

What parts of the PNS derive from the neural tube?

Answer 2

Pregangliotic autonomic nerves (sympathetic and parasympathetic)

All nerves that innervate skeletal muscles

Question 3

What are some of the proteins/factors that play a role in neurulation?

Answer 3

BMP-2, BMP-4

Sonic Hedgehog (Shh)

noggin

chordin

FGF-8 (fibroblast growth factor)

N-CAM (neural cell adhesion molecule)

Question 4

What factor does the notochord use to signal induction of the floor plate of the developing neural tube?

Answer 4

Sonic hedgehog (Shh)

Question 5

What are the two openings at both ends of the neural tube?

To what do they connect the lumen of the neural tube?

Answer 5

The Anterior and Posterior Neuropores

They connect the lumen of the neural tube with the amniotic cavity

Question 6

What does the anterior neuropore become?

When does it close?

What happens if it doesn’t close?

Answer 6

ANP -> Lamina Terminalis

It closes on day 25

Failure to close leads to anencephaly

Question 7

When does the posterior neuropore close?

What happens if it doesn’t close?

Answer 7

PNP closes on day 27

Failure to close leads to spina bifida

Question 8

The lumen of the neural tube gives rise to what?

Answer 8

The lumen of the neural tube gives rise to the ventricular system of the brain and central canal of the spinal cord

Question 9

What are the 3 primary brain vesicles?

When do they appear?

Answer 9

1. Prosencephalon (forebrain)
2. Mesencephalon (midbrain)
3. Rhombencephalon (hindbrain)

Appear during week 4

Question 10

What 2 flexures appear with the primary brain vesicles?

Answer 10

1. Cephalon flexure (midbrain flexure): between prosencephalon and rhombencephalon
2. Cervical flexure: located btwn rhombencephalon and future spinal cord

Question 11

What are the 5 secondary brain vesicles and their origins?

When do they appear?

Answer 11

1. Telencephalon: from prosencephalon
2. Diencephalon: from prosencephalon
3. Mesencephalon continues on from before
4. Metencephalon from rhombencephalon
5. Myelencephalon from rhombencephalon

Appear week 6

Question 12

What are the adult derivatives of the telencephalon?

Answer 12

Cerebral hemispheres, caudate, putamen, lamina terminalis, olfactory bulbs, hippocampus

Question 13

What are the adult derivatives of the diencephalon?

Answer 13

Thalamus and all the hypo, epi, thalami etc.
mammillary bodies, neurohypophysis (posterior pituitary), pineal gland,
many parts of the eye and optic nerve

Question 14

What are the adult derivatives of the metencephalon?

Answer 14

Pons, cerebellum

Question 15

What are the adult derivatives of the myelencephalon?

Answer 15

Medulla

Question 16

What new flexure is visible in the 7th week?

What does it become?

Answer 16

Pontine flexure

at the junction between the metencephalon and myelencephalon

Becomes the 4th ventricle and Rhomboid Fossa

Question 17

What are the adult derivatives of cranial neural crest cells?

Answer 17

• Pharyngeal arch: skeletal and connective tissue components
• Bones of neurocranium
• Pia mater and arachnoid
• Parafollicular (C) cells of thyroid
• Aorticopulmonary septum
• Odontoblasts (dentin of teeth)
• Some sensory and parasymphatic ganglia of cranial nerves (hopefully will not be important until after 1st midterm)