Development of the Peripheral System

Question 1

when is the critical period of embryo development

Answer 1

3-8 weeks and this is usually where things go wrong

Question 2

how are somites used clinically

Answer 2

can detect the age of the embryo with an ultrasound and depending on the number of the somites distinguish the age

Question 3

Peripheral Nervous System

Answer 3

Cranial nerves
spinal nerves
ganglia
Enteric plexus
Sensory receptors

Somatic=voluntary and carry sensory and motor

Autonomic= involuntary to smooth muscle and cardiac muscle and have both Motor and Sensory
-majority parasympathetic and sympathetic (technically motor)

Question 4

Dorsal horn is composed of

Answer 4

Sensory cell bodies

Question 5

Lateral Horn is composed of

Answer 5

Autonomic cell bodies

Question 6

Anterior horn is composed of

Answer 6

Motor cell bodies

Question 7

Dorsal Funiculus is composed of

Answer 7

Sensory axons that are mylenated (white)

Question 8

Anterior Funiculus is composed of

Answer 8

Primarily motor axons

Question 9

Lateral funiculus is composed of

Answer 9

sensory and motor axons

Question 10

Neural tube caudal to the 4th somite regions:

Answer 10

Alar plate
Basal Plate
Central canal

Question 11

Alar plate

Answer 11

sensory neurons that stay inside the brain, usually second and third order neurons

come from neuroectoderm

Question 12

Basal Plate

Answer 12

Motor structures like brachial plexus

Question 13

Central canal

Answer 13

hollow portion of the spinal cord tube

Question 14

what are the three zones and location

Answer 14

Ventricular zone: closest to central canal

Intermediate zone: middle layer and gives rise to grey matter

Marginal zone: outside layer and gives rise to the axons and white matter

Question 15

Ventricular zone structures

Answer 15

stem cells that make Ependymoblast which give rise to choroid plexus cell that creates Cerebrospinal fluid

also make ependymal cells

Question 16

Intermediate zone structures

Answer 16

gives rise to the neurons cell bodies as well as astrocytes and radial glial cells

grey matter

Question 17

Marginal zone structures

Answer 17

white matter

axons and oligodenrocytes which make mylein to put on the axons

Question 18

Mesenchymal cell orgin and what do they make in the CNS

Answer 18

come from mesoderm and produce microgilal cells

Question 19

Spinal cord positioning on newborns and why

Answer 19

L2 or L3 due to the growing of the bones because in the third month of the utero the spinal cord goes to the end of the spinal column

Question 20

Spinal cord positioning on adults

Answer 20

L1 or L2

Question 21

What does neural crest give rise to in the PNS

Answer 21

Spinal ganglion cells and sensory neurons in the periphery

Question 22

what does BMP do and what side is it released from

Answer 22

released from roof plate and epidermis on dorsal side

and gradient gets smaller as it goes done

High BMP activate PAX3 and PAX7 which give rise to alar plate (sensory neurons)

Question 23

what does SHH do and what side is it released from

Answer 23

released from Notochord and Floor plate on ventral side

activates NKX2.2 and NKX6.1 which gives rise to the basal plate

Question 24

Mixing of the BMP and SHH

Answer 24

occurs just dorsal of the basal plate where there are slightly lower SSH and higher levels of BMP activates NKX6.1 and PAK6 which makes up ventral Horn and ventral horn neurons

Question 25

Cells that develop from the Neural tube

Answer 25

motor neurons because the bodies are in the CNS

and preganglionic autonomic neurons (because located in lateral horn)

Question 26

Cells that develop from the neural crest

Answer 26

Neurons of the dorsal root ganglia, in the PNS
sensory of the Cranial Nerves
Schwann cells
sympathetic and parasympathetic ganglia

Question 27

Efferent Neurons

Answer 27

Motor derived from neuroectoderm
Somatic: motor ending on skeletal muscle

Visceral: Motor fibers that end about the autonomic ganglion cells which in turn control smooth muscle and cardiac and glands

Question 28

Afferent Neurons

Answer 28

Sensory derived from the neural crest

Somatic: sensory fibers that originate from the integument

Visceral : sensory fibers originating from the viscera

Question 29

Autonomic Nervous System

Answer 29

Motor:

Sympathetic and Parasympathetic

Question 30

Neural crest in Autonomic Nervous system:

Answer 30

formation of Autonomic ganglia and post synaptic cells

Question 31

Neuroectoderm in Autonomic Nervous system:

Answer 31

formation of the pre-ganglion cells and pre-synaptic cells

originate in the lateral horn

Question 32

Sympathetic Nervous system

Answer 32

Located in the spinal cord in the thoracolumbar region: T1-L2/3 in lateral horn

two link chain

Short mylenated Preganglionic (neuroectoderm) from spina cord to sympathetic ganglia
(neural crest)

long unmylenated postganglionic fiber to ganglia to viscera
(all neural crest)

Question 33

important sympathetic gaglion

Answer 33

Superior, middle and inferior cervical ganglion: all go to head and heart

Celiac ganglion
aorticorenal ganglion
superior mesenteric ganglion
inferior mesenteric ganglion

Question 34

Parasympathetic Cranial sacral region

Answer 34

CN 3, 7, 9, 10

sacral: 2nd, 3rd, and 4th sacral spinal nerves

Question 35

Parasympathetic two chain system

Answer 35

long mylenated (neuroectoderm) Preganglionic from spinal cord to parasympathetic ganglia

short unmylenated postganglionic fiber from ganglia to viscera (neural crest for all)

Ganglia found in wall of viscera

Question 36

important parasympathetic ganglia

Answer 36

cilary ganglion
pterygopalatine ganglion
submandibular ganglion
otic ganglion

all neural crest

Question 37

Oligodendrocytes

Answer 37

myelination in the CNS and starts in lower brain stem: older tracts first

6th months till 22 years old

neuroectoderm

Question 38

Schwann cells

Answer 38

PNS myelination
motor roots before sensory roots
4th month

neural crest