Development of the peripheral nervous system

Question 1

What composes the central nervous system?

Answer 1

The skull and spinal cord

Question 2

what composes the peripheral nervous system?

Answer 2

Cranial nerves, spinal nerves, ganglia, enteric plexus and sensory receptors

Question 3

What is the somatic nervous system?

Answer 3

It is a combination of sensory and motor neurons that have voluntary control over

Question 4

What is the autonomic nervous system?

Answer 4

It is a combination of sensory and motor neurons that are involuntarily controlled, like breathing

Question 5

What is the gray matter that is in the adult spinal cord?

Answer 5

The location of cell bodies in the neurons. divided into three sections, dorsal horn, lateral horn and anterior horn

Question 6

What type of neurons are present in the posterior horn of the gray matter?

Answer 6

Sensory neurons

Question 7

What type of neurons are present in the anterior horn of the gray matter?

Answer 7

motor neurons

Question 8

What type of neurons are in the lateral horn?

Answer 8

The visceromotor neurons

Question 9

What is the white matter in the spinal cord composed of?

Answer 9

The axons of neurons. These are usually mylenated so they will have a white appearance- divided into three sections- lateral funiculus, anterior funiculus and posterior funiculus

Question 10

what type of neurons are present in the anterior funiculus?

Answer 10

Primarily motor neurons

Question 11

What type of neurons are present in the posterior funiculus?

Answer 11

the sensory neurons

Question 12

The neural tube divides into what two sections during the formation of the spinal cord?

Answer 12

The alar and basal plate

Question 13

What composes the alar plate and what does it turn into?

Answer 13

the alar plate is composed of mostly afferent cells and it will become the anterior/ventral gray horn

Question 14

What composes the basal plate and what does it turn into?

Answer 14

It is composed of efferent cells and it will become the dorsal/posterior ventral gray horn

Question 15

What is the suclus limitans?

Answer 15

The groove that separates the alar and basal plates

Question 16

What are the three zones of the spinal cord?

Answer 16

The ventricular, intermediate and marginal zones

Question 17

what is the ventricular zones of the spinal cord?

Answer 17

The area closest to the central canal- composed neuroepithelial cells that will give rise to the neurons and macroganglia cells in the spinal cord. This is also where ependymoblast are

Question 18

What is the marginal zone of the spinal cord?

Answer 18

The outer layer of the spinal cord and composed of neuroepithelial cells that will develop into the white matter of the spinal cord

Question 19

What is in the intermediate area of the spinal cord?

Answer 19

The glioblast are in this zone and will eventually differentiate into the astrocytes and the oligodendrocytes- immature neurons are also here.

Question 20

What is a ependymoblast cell?

Answer 20

The stem cells of the CNS- They are housed in the ventricular portion of the spinal cord

Question 21

what do ependymoblast cells differentiate into?

Answer 21

they will form ependyma cells which will create the epithelium of the choroid plexus, producing the cerebral spinal fluid

Question 22

Neuroepithelium develops from what kind of ectoderm?

Answer 22

Neuroectorderm

Question 23

What does the neuroepithelium differentiate into and what section of the spinal cord does it go to?

Answer 23

a polar neuroblast- intermediate zone then marginal zones where it will be mylenated
glioblast- remain in the intermediate zone(gray matter)
ependyma- will remain in the ventricular zone and produce CSF

Question 24

What do the neural crest cells give rise to in the nervous system?

Answer 24

to the spinal ganglia and sensory neurons in the periphery

Question 25

How do the cells of the spinal cord differentiate into sensory or motor neurons?

Answer 25

It depends on the concentrations of BMP and SHH they receive during differentiation.

Question 26

What do high levels of BMP activate?

Answer 26

They will active the genes for PAX3 and PAX7 which will tell cells to differentiate into sensory neurons and incorporate into the alar plate

Question 27

What do high levels of SHH activate?

Answer 27

They will activate NKX2.2 and NKX6.1 which will tell cells to differentiate into motor neurons and incorporate into the basal plate

Question 28

What structures produce BMP?

Answer 28

The surface ectoderm and roof plate of the neural tube

Question 29

What structures produce SHH?

Answer 29

The notocord and floor plate of the neural tube

Question 30

What is a special case of the differentiation of neural tube cells?

Answer 30

Just dorsal there are slightly lower levels of SHH and higher levels of BMP so NKX6.1 and PAX6 will be activated- these cells become ventral neuron cells

Question 31

What does the posterior/dorsal root derive from?

Answer 31

From neural crest cells

Question 32

what does the anterior/ventral root derive from?

Answer 32

From neuroectoderm cells

Question 33

the Dorsal ramus will go innervate what and this derives from what type of mesoderm?

Answer 33

It will innervate the instrinsic back muscles and viscera that comes from the epimere epimere- myotome- paraxial mesoderm

Question 34

What does the anterior ramus innervate and what does this derive from>

Answer 34

It will innervate all other muscles and derives from hypomere hypomere- myotome- paraxial mesoderm

Question 35

What is GSE?

Answer 35

A general somatic efferent neuron- will arise from the ventral root and will innervate somatic muscles

Question 36

what is GVE?

Answer 36

A general visceral efferent neuron that will innervate smooth/cardiac muscles- comes off the ventral root

Question 37

What is SVE?

Answer 37

A Special visceral efferent neuron that will innervate muscles from the pharynegeal arches.

Question 38

What are GSE, GVE and SVE derived from?

Answer 38

Neuroectoderm

Question 39

What is GSA?

Answer 39

General somatic afferent neurons that will provide sensory info from the skin, joints, tendons or muscles- It is part of the posterior rami- Mostly innervates ectoderm and mesoderm near the area

Question 40

What is GVA?

Answer 40

General visceral afferent neurons that will provide sensory info from the visceral structures- part of the posterior rami- Mostly innervates the endoderm and mesoderm near the site

Question 41

What are GSA and GVA derived from?

Answer 41

Neural crest cells

Question 42

What is the sympathetic nervous system?

Answer 42

Part of the autonomic nervous system- used for the fight/flight response- located in t1-L2

Question 43

What part of the ANS is the neurocrest cells?

Answer 43

They compose the post ganglion response in the ANS

Question 44

What are of the ANS is the neuroectoderm cells?

Answer 44

They compose the pre ganglion response to the ANS

Question 45

Describe the pre and post ganglion portions of the sympathetic NS.

Answer 45

The preganglion synapse will be short and mylenated while the post ganglion synapse will be long and non-mylenated

Question 46

Describe the pre and post ganglion portions of the parasympathetic NS

Answer 46

The preganglion synapse is long and mylenated while the post ganglion synapse will be short and non-mylenated

Question 47

What is the parasympathetic NS?

Answer 47

It is the rest and digest system- CN 3, 7, 9 and 10 and the sacrum nerves- The ganglia are usually located in the wall of viscera or four cranial ganglia

Question 48

What mylenates neurons in the CNS?

Answer 48

oligodendrocytes which are derived from glioblast cells

Question 49

What mylenates the neurons of the PNS?

Answer 49

Schwann cells which are derived from neurocrest cells