Embryology: Development of the Peripheral Nervous System

Question 1

REMEMBER THIS**

Where does the smooth muscle, cardiac muscle, and the primitive blood come from?

Answer 1

The sphlanic extraembryonic mesoderm

Question 2

In the neural tube, what closure of somites will start to give rise to the brain?

Answer 2

The closure of the rostral 4th and 5th somites of the neural tube.

Question 3

In the neural tube, what closure of somites gives rise to the spinal cord?

Answer 3

The closure below the 4th and 5th somites of the neural tube.

Question 4

What proteins will activate the ventral patterning of the back spinal cord?

Answer 4

The proteins that give rise to the Basal Plate which are the Sonic Hedgehog Proteins (SHH proteins) that will activate the NKX 2.2 genes and the NKX 6.1 genes.

Question 5

What development of gene transcription does the SHH protein involve in?

Answer 5

SHH protein forms the Basal Plate which is the ventral side of the spinal cord. SHH Protein will activate NKX 2.2 and NKX 6.1 genes.

Question 6

What development of the gene transcription does the BMP proteins involve in?

Answer 6

BMP protein will activate the production of the Alar Plate and will allow for the dorsal development of the spinal cord. This is through the activation of the PAX3 and PAX7 genes.

Question 7

Oligodendrocites myelinate sheaths of?

Answer 7

CNS (Brain and Spinal Cord)

Question 8

Schwann Cells myelinate sheaths of?

Answer 8

The PNS (outer periphery neurons)

Question 9

Where should a lumbar puncture be down for an infanct whose spinal cord is still being developed?

Answer 9

It should be down below the L2-L3 area so that you don’t damage the spinal cord

Question 10

Where should a lumbar tap be done for an adult?

Answer 10

It should be done below the L1 region of the spinal cord because at this point the vertebral column has outgrownt he spinal cord in development.

Question 11

Where are the dorsal root ganglions coming from embryonically?

Answer 11

Neural Crest Cells

Question 12

What 2 embryonic structures will give rise to the PNS?

Answer 12

The Neural Crest Cells and the Ectodermal Placode

Question 13

What does the ectodermal placode give rise to?

Answer 13

Ectodermal Placode= motor peripheral nuerons of PNS, Autonomic neurons

Question 14

What are all the structures that are formed from the Neural Crest Cells?

Answer 14

All sensory neurons:
Neurons of the dorsal root ganglion
Sensory ganglia of cranial nerves (5,7,9,10)
Schwann Cells of PNS 
Sympathetic ganglia
parasympathetic ganglia

Question 15

Dorsal Root ganglion origin?

Answer 15

Neural Crest Cells

Question 16

Ventral Root ganglion origin?

Answer 16

Ectodermal Placode

Question 17

Spinal Nerve?

Answer 17

Mixed sensory and motor components–>

BOTH neural crest cells & ectodermal placode

Question 18

Dorsal Ramus?

Answer 18

Mixed: Sensory and motor components–>
BOTH neural crest cells & ectodermal placode

***will innervate all the true back muscles that originate from the epimeres of the epaxial myotome

Question 19

Ventral Rami?

Answer 19

Will be mixed: Innervated by both sensory and motor neurons

***Results in: hypomere of hypaxial mesoderm

Question 20

Where do all the afferent neurons develop from in the PNS?

Answer 20

They will develop from the neural crest cells
Ex: 
general somatic afferent nuerons
general visceral afferent neurons
special visceral afferent neurons
special somatic afferent neurons

Question 21

Where do all the efferent neurons develop from the PNS?

Answer 21

These are all motor neurons:
Neural Ectoderm--> Ectodermal Placode
General somatic efferent neurons
general visceral efferent neurons
special visceral efferent neurons
special somatic efferent neurons