Peripheral Nervous System (Megan) Flashcards
1
Q
Brain + spinal cord
A
Central nervous system (CNS)
2
Q
Nervous structures outside CNS CNS Body
A
Peripheral nervous system (PNS)
3
Q
PNS consists of these four nerves/systems:
A
-spinal nn. -cranial nn. -enteric system -visceral nerves and plexuses
4
Q
PNS consists of two types of structures:
A
Somatic and visceral
5
Q
Skin and striated muscles
A
Somatic tissue
6
Q
viscera + cardiac and smooth mm. + glands + blood vessels + arrector pili m.
A
Visceral tissue
7
Q
What are the two types of neurons and innervations?
A
sensory ≈ afferent motor ≈ efferent
8
Q
Group of cell bodies (outside CNS)
A
Ganglion
9
Q
Bundle of axons surrounded by connective tissue
A
Peripheral nerve
10
Q
Surround axons and dendrites and give them their white color
A
myelin sheaths.
11
Q
Nerve cells
A
neurons
12
Q
Cell bodies are a ____ color.
A
gray
13
Q
dendrite and axons are the color _____ because they are surrounded by layer of protein tissue, known as the myelin sheath.
A
white
14
Q
You will find motor cell bodies in
A
ventral
15
Q
you will find sensory cell bodies in
A
dorsal
16
Q
dorsal group and ventral group form the
A
spinal nerves
17
Q
what emerges from the spinal cord?
A
spinal nerve
18
Q
Spinal nerves are connected to spinal cord by
A
ventral rootlets and root; dorsal rootlets and root.
19
Q
Ventral root + dorsal root = ? (lateral to spinal cord)
A
spinal nerve
20
Q
Gives rise to a single pair of spinal nn.
A
Spinal segment
21
Q
Spinal n. through ________
A
Intervertebral foramen
22
Q
Division of spinal n. into…
A
dorsal ramus and ventral ramus
23
Q
Epaxial mm. + skin on back
A
Dorsal ramus
24
Q
Skin + skeletal (hypaxial) mm. of ventro-lateral aspects of body (=limb + trunk mm.)
A
Ventral ramus
25
Skin of certain parts of head are innervated by the \_\_\_\_\_\_\_\_\_\_\_
cranial nn.
26
How many pairs of spinal nerves?
31
27
How many cervical spinal nn.?
8 (C1-C8)
28
How many thoracic spinal nn.?
12 (T1-T12)
29
How many lumbar spinal nn.?
5 (L1-L5)
30
How many sacral spinal nn.?
5 (S1-S5)
31
How many coccygeal spinal n.?
1 (Co1)
32
Cervical spinal nerves exit ____ cervical vertebrae with same name/number
Above
33
All other spinal nerves exit _______ vertebrae with same name/number
Below
34
Somatic NS consist of
C1-Co1 spinal nn.
35
31 pairs of somites with (2 answers)
dermatomes myotomes
36
skin precursor cells
dermatomes
37
muscle precursor cells
myotomes
38
dermatomes and myotomes develop into what?
skin and striated muscles
39
Innervation of dermatomes + myoterms by...
somatic nerves
40
A segment of striated muscle + overlying skin; target area for spinal nn.
Dermamyotome
41
Portion of skeletal muscle innervated by a single pair of spinal nerve from a specific spinal cord level C1-Co1.
Myotome
42
This portion of the skeletal muscle has more than one spinal n./spinal cord level for each skeletal muscle. Difficult clinical testing
Myotome
43
Area of skin innervated by a single pair of spinal nerves entering a specific spinal cord level C1-Co1. Clinical testing by touch in conscious patients.
Dermatome
44
Skin overlying limbs, lateral and anterior walls of the thorax
Ventral rami territory
45
Both ventral and dorsal rami contribute to \_\_\_\_\_.
Dermatomes
46
Muscles and skin of anterior and lateral trunk of limbs
Hypaxial dermamyotome
47
Collection of sensory neurons at the distal end of dorsal root, usually in intervertebral foramen.
Dorsal root ganglion (DRG; aka spinal ganglion)
48
● motor and sensory innervation to epaxial muscles and overlying skin
● strictly segmental
Ø Exception: Greater occipital n. (C2 dorsal ramus; pure sensory)
Dorsal rami
49
* motor and sensory fibers
* not necessarily segmental
* formation of plexus for limb innervation
* origin in back (intervertebral foramina)
* innervation of ventral and lateral structures
Ventral rami
50
Ventral rami from more than one spinal cord segment form into this
Plexus
51
Fibers from several _______ in nerves emerging from a plexus
(e.g. Axillary n. (C5-C6 ventral rami) from brachial plexus → Deltoid m. (C5-C6 myotomes))
ventral rami
52
\_\_\_\_\_\_\_\_\_\_ nerves for monitor changes in viscera (e.g., chemoreception, mechanoreception, and stretch reception)
sensory
53
\_\_\_\_\_\_\_\_\_\_\_\_ nerves innervate smooth mm. + cardiac mm. + glands + blood vessels
Motor
54
Motor component
Autonomic Nervous System (ANS)
55
2 neurons/fibers in autonomic innervation:
1 pre-ganglionic (myelinated) neuron in CNS
1 post-ganglionic (un-myelinated) neuron in peripheral ganglion
56
Exit of peripheral autonomic nerves from CNS: in the cranial region, from ....
CN III, VII, IX, and X
57
Exit of peripheral autonomic nerves from CNS: in the spinal cord, from ..........
T1-L2 and S(2)3-S4(5) levels
58
▪ travel with autonomic nerves, and not separable in dissection
▪ NOT part of sympathetic and parasympathetic systems
▪ 1 neuron in dorsal root ganglion
Visceral sensory nerves
59
Visceral motor and sensory fibers enter and exit CNS with their _______ equivalents
somatic
60
Structures that receive visceral innervation:
● All thoracic organs…
● All abdomino-pelvic organs…
● Body wall structures (arrector pili m. + sweat glands + sebaceous glands + smooth muscles in walls of blood vessels)…
61
All thoracic organs innervations (2)
* autonomic innervation
* visceral sensory innervation
62
All abdomino-pelvic organs innervation
* autonomic innervation
* visceral sensory innervation
63
Body wall structures (arrector pili m. + sweat glands + sebaceous glands + smooth muscles in walls of blood vessels) innervation
* partial autonomic innervation
* visceral sensory innervation
64
2 components of autonomic nervous system (ANS):
● sympathetic (energy expenditure)
● parasympathetic (energy intake/conservation)
65
Origin of autonomic innervation in CNS:
* sympathetic from T1-L2 segments of spinal cord
* parasympathetic from brainstem (via CN III, VII, IX, and X) and S(2)3-S4(5) segments of spinal cord
66
Pre-ganglionic neurons in lateral horns of T1-L2 spinal cord segments
Sympathetic NS
67
● located outside CNS
● formation of long chain on either side of vertebral column (paravertebral or sympathetic chain ganglia)
● sympathetic ganglia in abdominal and pelvic cavities (subdiaphragmatic/pre- vertebral/pre-aortic ganglia)
● convergence of two chains anterior to coccyx at ganglion impar
● paravertebral ganglia attached to ventral rami of spinal nn.
sympathetic ganglia
68
suspension of paravertebral ganglia from ventral rami by…
white ramus communicans (T1-L2 spinal cord levels)
69
Identify preganglionic, post ganglionic, and synapse.
preganglionic - solid line
synapse
post ganglionic - dashed lines
70
Innervation of thoracic organs:
T1-T5 lateral horn → Ventral horn → Ventral rootlets → Ventral root → Spinal n. → Ventral ramus → White ramus communicans → Paravertebral ganglia (synapse)\* → Sympathetic “organ” n. → Target organ
71
Some pre-ganglionic fibers ascend the sympathetic chain via inter-ganglionic communicating bundle, go to cervical sympathetic ganglia (superior + middle + inferior/stellate) and _____ there.
synapse
72
Organs in the abdomen and pelvis receive their pre-ganglionic innervation from between
T5-L2
74
Innervation of abdomino-pelvic organs (high yield):
T5-L2 lateral horn → Ventral horn → Ventral rootlets → Ventral root → Spinal n. → Ventral ramus → White ramus communicans → Paravertebral ganglia (NO synapse) → Splanchnic nn. → Subdiaphragmatic ganglia (synapse) → Post-ganglionic fibers to blood vessels → Target organ(s)
75
Some pre-ganglionic fibers in the splanchnic nerves do not synapse in the subdiaphragmatic ganglia, but pass through the system to adrenal glands where they synapse directly on the adrenal \_\_\_\_\_\_\_\_\_
medulla.
76
Spinal cord contributions to splanchnic nerves:
▪ T5-T9 = \_\_\_\_\_\_\_
▪ T(9)10-T(10)11 = \_\_\_\_\_\_.
▪ T12 = \_\_\_\_\_\_\_\_
▪ L1-L2 = \_\_\_\_\_\_\_\_\_
▪ T5-T9 = Greater splanchnic n.
▪ T(9)10-T(10)11 = Lesser splanchnic n.
▪ T12 = Least splanchnic n.
▪ L1-L2 = Lumbar splanchnic n.
77
Innervation of body wall structures at T1-L2 levels:
T1-L2 lateral horn → Ventral horn → Ventral rootlets → Ventral root → Spinal n. → Ventral ramus → White ramus communicans → Paravertebral ganglia (synapse) → (post-ganglionic fibers in) Gray ramus communicans → Ventral ramus → Ventro-lateral aspect of body wall
78
To reach dorsal aspect of body wall, post-ganglionic fibers travel from …
Ventral ramus → Spinal n. → Dorsal ramus → Dorsal aspect of body wall
79
Innervation of body wall structures OUTSIDE T1-L2 levels:
T1-L2 lateral horn → Ventral horn → Ventral rootlets → Ventral root → Spinal n. → Ventral ramus → White ramus communicans → Paravertebral ganglia (NO synapse) → Inter-ganglionic communicating bundle → Sympathetic chain (ascend/descend to higher/lower sympathetic ganglia) → Synapse → (post-ganglionic fibers in) Gray ramus communicans → Ventral ramus → Ventro-lateral aspect of body wall
80
To reach dorsal aspect of body wall (outside T1-L2 levels) post-ganglionic fibers travel from …
Ventral ramus → Spinal n. → Dorsal ramus → Dorsal aspect of body wall
81
● carried by CN III, VII, IX, and X
● CN III + VII + IX to structures in head and neck only (wait until block 4…)
● CN X (Vagus n.) to structures in head and neck + thorax + partial abdomen
Vagus n. → Thoracic + abdominal viscera up to left colic flexure (synapse on ganglia in organ walls)
Cranial parasympathetics
82
● S(2)3-S4(5) spinal cord segments
● viscera of hindgut + pelvis + perineum + blood vessels associated with erectile tissues
S(2)3 – S4(5) lateral horn → Ventral horn → Ventral rootlets → Ventral root → Spinal n. → Ventral ramus → Pelvic splanchnic n. → Viscera in hindgut + pelvis + perineum (synapse on ganglia in organ walls)
Sacral parasympathetics
83
Parasympathetic innervation to body wall structures…
THERE ARE NONE! :)
84
Functions of Sympathetic NS:
● energy expenditure (“fight or flight”)
● stimulation of sweat glands for heat dissipation
● constriction of cutaneous arterioles → shunt blood to muscles
● dilation of cutaneous arterioles → heat dissipation
● bronchodilation
● dilation of coronary + muscular arterioles → greater blood supply to heart and muscles
● dilation of pupils
● constriction of gastro-intestinal blood vessel
● reduction in bowel activity
85
Functions of Parasympathetic NS
● energy intake/conservation
● bronchoconstriction
● constriction of coronary blood vessels
● reduction in heart rate
● constriction of pupils
● dilation of gastro-intestinal blood vessels
● increase in peristalsis
● stimulation of exocrine digestive glands
● defecation/urination → solid/liquid waste disposal
86
Not part of ANS, sensory cell bodies at dorsal root ganglion (non-synaptic), Non-sensory afferent information, do not reach level of consciousness, connect to autonomic motor system for visceral, reflex
usually dull, poorly localized. Stimuli for pain: ischemia, inflammation, distension, cramping, cutting, crushing, burning
Distension of pelvic organs… follows parasympathetic out-flow
PNS: Visceral Sensation
87
Visceral sensation follows ______ outflow (Spinal nerve, goes back to spinal cord by the dorsal root, dorsal rootlets, dorsal horn.)
Sympathetic
88
* Viscero-somatic convergence in dorsal horn
* Visceral sensation (pain) interpreted as sharp, well- localized (somatic) pain from an undamaged region of body wall
* Both injured visceral structure and undamaged body wall region innervated by same spinal cord segments
PNS: Referred pain
Green lines in photo: visceral sensory
Red lines in photo: somatic sensory
89
Pain from the heart (T1 – T5 sympathetic innervation) referred to dermatomes T1 – T5 on left side
Angina pectoris
90
RIGHT SIDE T7-T9; pain from kidney (T10-T12). referred pain visceral to referred somatic. Sensory information or pain sensation from the structures will go back to the same spinal cord segments and found in the dermatomes.
Appendicitis
91
What does this image show?
Motor and Sensory cell bodies.
92
PNS Enteric system is located within walls of the \_\_\_\_\_
GI tract
93
Enteric system is made up of ______ and ______ neurons.
motor and sensory
94
Two inter-connected nerve plexuses in enteric system
myenteric
submucous
95
Plexus formed by…
● ganglia containing neurons
● nerve fiber bundles connecting ganglia and surrounding tissues
96
Reflex activities of \_\_\_\_\_\_\_\_:
* regulation of peristalsis, secretomotor activity, and vascular tone
* independent of CNS
* possible modification by pre-ganglionic parasympathetic and post-ganglionic sympathetic fibers
GI tract
97
Sensory in-flow to CNS by _______ afferent fibers
visceral
98
What is this image showing?
Nerve plexuses
99
Somatic or visceral
Network of fibers from different sources/spinal cord segments…
● formation of new nerves with specific targets/destinations
Nerve Plexuses
100
Cervical (C1-C4 ventral rami)
Brachial (C5-T1 ventral rami)
Lumbar (L2-L4 ventral rami)
Sacral (L5-S3 ventral rami)
Coccygeal (S5-Co1 ventral rami)
Somatic plexuses
101
● formed in association with viscera
● contain visceral motor and sensory fibers
● cardiac + pulmonary + esophageal + aortic plexuses for thoracic viscera
Visceral plexuses
