PNS Flashcards
epineurium
outermost layer of connective tissue; dense, includes collagen fibers
perineurium
loose connective tissue that surrounds fascicles (bundles of nerve fibers)
endoneurium
loose connective tissue that surrounds individual nerve fibers
cranial nerves
12 pairs; 1st from cerebrum, last 11 from brain stem
ganglia
bundles of neurons outside CNS
CN I
olfactory; associated with sense of smell; sensory
CN II
optic; associated with vision; sensory
CN III
oculomotor; associated with eye movement; motor; both somatic and autonomic
CN IV
trochlear; motor to superior oblique muscle
CN V
trigeminal, largest, from pons, sensory and motor
CN V1
ophthalmic; impulses from surface of eye, tear gland, skin of the anterior scalp, upper eyelid; sensory
CN V2
maxillary; upper teeth, gums, lip, mucous lining of palate and facial skin; sensory
CN V3
mandibular; both sensory and motor; floor of mouth, scalp behind ears, muscles of mastication and some on the floor of the mouth
CN VI
abducens; abducts the eye, originate from medulla oblongata; motor
CN VII
facial; both sensory and motor; muscles of facial expression
CN VIII
vestibulocochlear; sensory for hearing and balance; vestibular located in ganglia in inner ear; cochlear in ganglia of cochlea for hearing
labyrinthitis
inflammation of CN VIII, varying degrees of vertigo
CN IX
glossopharyngeal; tongue and pharynx; both sensory and motor
CN X
vagus; both sensory and motor; only nerve to extend beyond head and neck
CN XI
accessory nerve; originate in medulla oblongata and spinal cord; cranial branch joins vagus; spinal supplies motor fibers to trapezius and SCM muscles; motor
CN XII
hypoglossal; motor; arise from medulla oblongata
cervical nerves
8 pairs (C1-C8); 1-7 exit above, 8th exits below
thoracic nerves
12 pairs (T1-T12); exit below
lumbar nerves
5 pair (L1-L5); exit below
sacral nerves
5 pairs (S1-S5); exit below
coccygeal nerves
1 pair (C0); exit below
cauda equina
where the spinal cord ends in an adult around L1-2
2 branches of spinal nerve
dorsal root
ventral root
dorsal root
sensory/afferent; identified by dorsal root ganglion (enlargement) containing sensory neurons that conduct impulses inward from peripherals; back door
ventral root
motor/efferent; motor neurons in gray matter of cord; front door
recurrent meningeal branch
reenters vertebral canal and supplies meninges and blood vessels of the cord
dorsal ramus
turns posteriorly; innervates muscles and skin of back
ventral ramus
continues forward to supply muscles and skin on the front and sides of trunk/limbs
visceral branch
arise from spinal nerves in thoracic and lumbar regions; autonomic NS
grey rami communicantes
everywhere; parasympathetic
white rami communicantes
sympathetic; T1-L2 only
plexus
complex network of fibers that are sorted and recombined
cervical plexus
branches of the first 4 cervical nerves, supply muscles and skin of neck
phrenic nerves
C3-5; regulate diaphragm
brachial plexus
ventral rami of lower 4 cervical nerves and 1st thoracic
musculocutaneous nerve
C5-7; anterior arm muscles, skin of forearm
ulnar nerve
C8-T1; muscles of forearms, hands and skin
median nerve
C5-T1; muscles of forearms, hands and skin
radial nerve
C5-T1; muscles of arms on posterior; skin of forearms and hands
axillary nerve
C5-6; muscles of skin of superior, lateral, posterior regions of arm
lateral pectoral nerve
C5-7
medial pectoral nerve
C8-T1
dorsal scapular nerve
C5
lower subscapular nerve
C5-6
thoracodorsal nerve
C6-8
suprascapular nerve
C5-6
long thoracic nerve
C5-7
lumbar plexus
ventral rami of lumbar nerves 2-4
