peripheral nervous system

Question 1

where does PNS originate from

Answer 1

Neural crest cells

Question 2

Types of cells in the PNS besides neurons

Answer 2

satellite cells
schwann cells

Question 3

what is the type of cell that myelinates neurons in the CNS, as opposed the PNS

Answer 3

oligodendrocytes

Question 4

sensory neurons enter the brainstem/spinal cord at what position

Answer 4

the dorsal and lateral

Question 5

where do motor neurons exit the brainstem/ spinal cord

Answer 5

at the ventral and medial position

Question 6

cell bodies of sensory neurons are located where

Answer 6

dorsal root ganglia (DRG)

Question 7

motor neuron cell bodies are found in the

Answer 7

ventral horn

Question 8

larger more myelinated fibers have a ___ conduction speed

Answer 8

faster

Question 9

Sensory neurons: afferent = arriving;

Answer 9

carry sensory information from periphery → CNS
o Pseudo-unipolar and bipolar neurons

Question 10

Motor neurons: efferent = exiting

Answer 10

information from CNS → periphery (e.g., muscle)
o Projections neurons

Question 11

Satellite cells

Answer 11

surround cell body
1. General support of peripheral neurons
2. Protect neurons after damage
3. Contribute to inflammation and chronic pain

Question 12

Schwann cells:
cover axons
1. Provide myelination
2. Remyelinate axons after damage

Answer 12

T

Question 13

Large, myelinated fibers =

Answer 13

fastest

Question 14

Small, unmyelinated fibers =

Answer 14

slowest

Question 15

sympathetic nervous system

Answer 15

fight or flight
location thoracolumbar spinal nerves connecting to sympathetic trunk

Question 16

parasympathetic nervous system

Answer 16

rest and digest.

Question 17

location of PNS

Answer 17

craniosacral
cranial nerves- oculomotor (CNIII), facial (CNVII), glossopharyngeal
(CNIX), vagus nerve (CNX) and sacral spinal nerves

Question 18

controls skeletal muscles
allows for concious control

Answer 18

somatic

Question 19

autonomic

Answer 19

controls smooth mucles, cardaic muscles and glands, operates involuntrarily like digesting food

Question 20

motor neurons of _____ extend directly from the CNS to the target muscle without synapsing in a ganglion

Answer 20

somatic nervous system

Question 21

single neuron pathway healvily myelinated

Answer 21

somatic

Question 22

Short, lightly myelinated preganglionic axons
Synapses and releases acetylcholine
(Ach) w/in sympathetic chain ganglia,
prevertebral (collateral) ganglia, or
synapses on adrenal medulla which acts as a ganglion
Typically long, unmyelinated
postganglionic axon which releases
norepinephrine (NE)
Adrenal medulla releases both NE
and epinephrine (E)

Answer 22

Sympathetic:

Question 23

Long, lightly myelinated preganglionic axon
Synapses and releases Ach w/in
intramural ganglia
Very short, intramural postganglionic axon releases Ach w/in target tissue

Answer 23

Parasympathetic

Question 24

Enteric Nervous System

Answer 24

lining of GI tract from esophagus to anus

Question 25

• Regulates muscles of GI tract, carries sensory info
• Modulated by parasympathetics/sympathetics BUT can function in absence of ANS input

Answer 25

enteric nervous system

Question 26

inhibits ENS; via lateral horn of spinal cord

Answer 26

Sympathetics

Question 27

T or F
Enteric glia between muscle layers plays a role in chronic inflammation and pain

Answer 27

T

Question 28

stimulates ENS; via vagus nerves and sacral splanchnic nerves

Answer 28

parasympathetics

Question 29

fills space around individual axons
outside Schwann cells

Answer 29

Endoneurium

Question 30

surrounds axons
Protective covering, made up of several layers of epithelium
If many axons → fascicle = bundle of axons
▪ Axons can branch and cross into other fascicle forming collateral connections
* Target multiple organs simultaneously
▪ Around joints, fascicles thinner, more numerous, and have thicker perineum to
protect against movement and pressure

Answer 30

Perineurium

Question 31

outermost layer of dense tissue
Connective tissue sheath surrounding fascicles and blood vessels
Merges with adipose tissue

Answer 31

Epineurium

Question 32

network of both sensory and motor axons
o Nerve fibers from different spinal nerves combine so all fibers travel
to one area of body
o Think of as electrical wires converging to travel in one direction

Answer 32

Plexus

Question 33

area of skin supplied by a single spinal nerve
o Sensory innervation corresponds to an individual spinal cord level
o Clinically relevant as symptoms (e.g., pain, loss of sensation, rash) in these distinct areas
of skin can be localized to a specific spinal nerve to determine pathology
▪ Example: Shingles outbreak typically occurs along ___

Answer 33

Dermatome

Question 34

referred pain is closely related to ____ and ____

Answer 34

dermatomes and dorsal root ganglia

Question 35

Referred pain: pain perceived in outer body or skin
caused by pain from visceral organ
o Visceral sensory pain travels along ANS pathway to spinal cord where it converges with
somatic sensory (afferent) pathway within
dorsal horn
▪ Sensory (afferent) neurons converge in
the dorsal root and motor (efferent)
neurons converge in the ventral root.

Answer 35

Referred pain follows dermatomes,
which are sensory fibers, while
myotomes (which are not involved in
referred pain) are motor fibers
o Brain misinterprets visceral pain as somatic pain
o Example: pain down left arm experienced during heart attack

Question 36

muscles served by single spinal nerve
o Weakness in muscle or specific muscle group can indicate nerve injuries

Answer 36

Myotome

Question 37

Control of motility: peristalsis, churning, sphincter
muscles

Answer 37

Motor input (ANS)

Question 38

Regulation of gastric secretions, pancreatic enzymes, bile
Regulation of fluid exchange and blood flow

Answer 38

motor input (ANS)

Question 39

Sensory output (somatic): → thoracic, lumbar, sacral neurons

Answer 39

o Pain and discomfort
o Detection of distension and GI contents