15. Development of the PNS Flashcards

1
Q

If something is going to go wrong during development when will it most likely take place?

A

Weeks 3-8 are the critical period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 2 major divisions of the nervous system?

A

Central Nervous System (CNS)

  • Brain
  • Spinal Cord

Peripheral Nervous System (PNS)

  • Cranial nerves
  • Spinal nerves
  • Ganglia
  • Enteric plexus
  • Sensory receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the gray matter of the spinal cord

A
  • Location of cell bodies of neurons
  • Dorsal (posterior) horn: sensory
  • Lateral horn: autonomics
  • Anterior (ventral) horn: motor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the white matter of the spinal cord

A
  • Location of axons
  • Dorsal (posterior) funiculus: sensory
  • Lateral funiculus: sensory and motor
  • Anterior (ventral) funiculus: primarily motor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Somatic vs Autonomic nervous system

A

Somatic:

  • voluntary control
  • skeletal muscle contration
  • to the body (Median N)

Autonomic:

  • involuntary control
  • parasympathetic/Sympathetic
  • smooth muscle
  • cardiac muscle
  • glands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the structures fo the Sulcus Limitans

A

Alar Plate: sensory neurons

Basal Plate: motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is the neural tube located in relation to somites?

A

Caudal to 4th pair of somites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 3 zones of the central canal or neural canal?

A
  1. Ventricular Zone
    - choroid plexus
    - ependymal cell
    - ependymoblast
    - germinal or ventricular cell
  2. Intermediate Zone (mantle layer) (gray matter)
    - neuron
    - glioblast
    - radial glial cell
    - astrocyte
  3. Marginal Zone (white matter)
    - oligodendrocyte
  • Everything is Ectoderm
  • Microglial and mesenchymal cells are coming from mesoderm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the position of the spinal cord in a newborn vs an adult?

A

Newborn: L2 or L3

Adult: L1 or L2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

_________ cells give rise to spinal ganglion cells and sensory neurons in the periphery

A

Neural crest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the concentration gradients that form the spinal cord?

A

Dorsal (sensory) and ventral (motor) region dependent on concentration gradients

Dorsal: High BMP levels activate PAX3 and PAX7 = sensory neuron differentiation = alar plate

Ventral: High SHH levels activate NKX2.2 and NKX6.1 = ventral neuron formation = basal plate
- (Just dorsal there are slightly lower SSH and higher levels of BMP activate NKX6.1 and PAX6 = ventral motor neurons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the development of the PNS

A

The neural crest and ectodermal placode
form the PNS

Cells that develop from the neural tube

include: (neuro ectoderm)
- motor neurons
- pre-ganglionic autonomic neurons

Cells that develop from the neural crest include: (neural crest)

  • Neurons of dorsal root ganglia
  • Sensory ganglia of cranial nerves
  • Schwann cells
  • Sympathetic ganglia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe a typical segmental nerve

A

• Dorsal root (sensory)
– Spinal ganglion (dorsal root ganglion)

  • Ventral root (motor)
  • Spinal nerve (mixed)

• Dorsal ramus (mixed)
– Motor to dorsal muscles
– Sensory to dorsal integument

• Ventral ramus (mixed)
– Motor to limbs, lateral and ventral body wall
– Sensory to integument of same regions

• Ramus communicantes
– Motor and sensory to viscera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the general characteristics of Afferent neurons?

A
Afferent (sensory) (Neural crest)
– Somatic: Sensory fibers originating
chiefly from integument
– Visceral: Sensory fibers
originating from viscera
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the autonomic nervous system?

A

• Innervation of smooth muscle, cardiac muscle and glands.

• Consists of two motor paths
– Sympathetic
– Parasympathetic

  • Neural crest- formation of ganglia and post-ganglion cells.
  • Neuroectoderm – formation of the pre-ganglion cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the sympathetic nervous system?

A

Located in the spinal cord in the thoraco-lumbar region

Two link chain:
– Preganglionic from spinal cord to sympathetic ganglia
– Postganglionic fiber from ganglia to viscera

17
Q

What is the sympathetic nervous system?

A

Located in the spinal cord in the thoraco-lumbar region
(T1-L2/3) (lateral horn)

Two link chain:
– Preganglionic from spinal cord to sympathetic ganglia (myelinated)
– Postganglionic fiber from ganglia to viscera (un-myelinated)

18
Q

List the major sympathetic ganglia listed in class

A

Superior, Middle and Inferior Cervical ganglion come from neural crest

Prevertebral Ganglia (sympathetic ganglia)

  • Celiac ganglion
  • aortic or renal ganglion
  • superior and inferior mesenteric ganglion
19
Q

What is the parasympathetic nervous system?

A

Parasympathetic
• Cranial-sacral region
– Cranial: primarily cranial nerves (3, 7, 9, 10)
– Sacral: 2nd to 4th sacral spinal nerves (GVE)

• Neural crest components

• Two link chain
– Preganglionic from spinal cord to sympathetic ganglia
– Postganglionic fiber from ganglia to viscera

• Ganglia
– Usually in wall of viscera
– Four cranial ganglia

20
Q

Give some examples of parasympathetic ganglia

A
  • Ciliary
  • Otic
  • Submandibular
  • Ptergopalatine
21
Q

Describe the myelination of CNS and PNS neurons

A

Form during late fetal period
• Continue into first postnatal year

• CNS: oligodendrocytes
– Starts in lower brain stem
• Older tracts first
– 6th month through puberty

• PNS: Schwann cells
– Motor roots myelinated before sensory roots
– 4th month

22
Q

Sensory neurons of the radial nerve are derived from:

A. Neural crest cells
B. Basal lamina cells
C. Alar lamina cells
D. Surface ectoderm

A

A. Neural crest cells

23
Q

Which of the following cells is not derived from the ventricular zone of the neural tube?

A. Oligodendrocyte
B. Astrocyte
C. Schwann cell 
D. Ependymoblast 
E. Glioblast
A

C. Schwann cell

24
Q

Which of the following are basal lamina derivatives?

A. Spinal cord sensory neurons
B. Spinal cord motor neurons
C. Spinal ganglia
D. Dorsal root

A

B. Spinal cord motor neurons

25
Q

The caudal neuropore normally closes in which week of the fertilization calendar?

A. Week 2
B. Week 3
C. Week 4 (1st month)
D. Week 8 (2nd month)
E. Week 12 (3rd month)
A

C. Week 4 (1st month)

26
Q

The myelin sheaths of axons in the central nervous system are formed by:

A. Microglia
B. Oligodendrocytes
C. Astrocytes
D. Schwann cells
E. Ependymal cells
A

B. Oligodendrocytes

27
Q

Preganglionic sympathetic cell bodies develop from:

A. Neural crest
B. Mesoderm
C. Alar plate
D. Basal plate

A

D. Basalplate

28
Q

Postganglionic parasympathetic cell bodies develop from:

A. Neural crest
B. Mesoderm
C. Alar plate
D. Basal plate

A

A. Neural crest