Development of the Peripheral System Flashcards

1
Q

when is the critical period of embryo development

A

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

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2
Q

how are somites used clinically

A

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

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3
Q

Peripheral Nervous System

A
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)

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4
Q

Dorsal horn is composed of

A

Sensory cell bodies

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5
Q

Lateral Horn is composed of

A

Autonomic cell bodies

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6
Q

Anterior horn is composed of

A

Motor cell bodies

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7
Q

Dorsal Funiculus is composed of

A

Sensory axons that are mylenated (white)

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8
Q

Anterior Funiculus is composed of

A

Primarily motor axons

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9
Q

Lateral funiculus is composed of

A

sensory and motor axons

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10
Q

Neural tube caudal to the 4th somite regions:

A

Alar plate
Basal Plate
Central canal

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11
Q

Alar plate

A

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

come from neuroectoderm

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12
Q

Basal Plate

A

Motor structures like brachial plexus

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13
Q

Central canal

A

hollow portion of the spinal cord tube

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14
Q

what are the three zones and location

A

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

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15
Q

Ventricular zone structures

A

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

also make ependymal cells

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16
Q

Intermediate zone structures

A

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

grey matter

17
Q

Marginal zone structures

A

white matter

axons and oligodenrocytes which make mylein to put on the axons

18
Q

Mesenchymal cell orgin and what do they make in the CNS

A

come from mesoderm and produce microgilal cells

19
Q

Spinal cord positioning on newborns and why

A

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

20
Q

Spinal cord positioning on adults

21
Q

What does neural crest give rise to in the PNS

A

Spinal ganglion cells and sensory neurons in the periphery

22
Q

what does BMP do and what side is it released from

A

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)

23
Q

what does SHH do and what side is it released from

A

released from Notochord and Floor plate on ventral side

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

24
Q

Mixing of the BMP and SHH

A

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

25
Cells that develop from the Neural tube
motor neurons because the bodies are in the CNS and preganglionic autonomic neurons (because located in lateral horn)
26
Cells that develop from the neural crest
Neurons of the dorsal root ganglia, in the PNS sensory of the Cranial Nerves Schwann cells sympathetic and parasympathetic ganglia
27
Efferent Neurons
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
28
Afferent Neurons
Sensory derived from the neural crest Somatic: sensory fibers that originate from the integument Visceral : sensory fibers originating from the viscera
29
Autonomic Nervous System
Motor: Sympathetic and Parasympathetic
30
Neural crest in Autonomic Nervous system:
formation of Autonomic ganglia and post synaptic cells
31
Neuroectoderm in Autonomic Nervous system:
formation of the pre-ganglion cells and pre-synaptic cells | originate in the lateral horn
32
Sympathetic Nervous system
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)
33
important sympathetic gaglion
Superior, middle and inferior cervical ganglion: all go to head and heart Celiac ganglion aorticorenal ganglion superior mesenteric ganglion inferior mesenteric ganglion
34
Parasympathetic Cranial sacral region
CN 3, 7, 9, 10 | sacral: 2nd, 3rd, and 4th sacral spinal nerves
35
Parasympathetic two chain system
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
36
important parasympathetic ganglia
cilary ganglion pterygopalatine ganglion submandibular ganglion otic ganglion all neural crest
37
Oligodendrocytes
myelination in the CNS and starts in lower brain stem: older tracts first 6th months till 22 years old neuroectoderm
38
Schwann cells
PNS myelination motor roots before sensory roots 4th month neural crest