Download CHAPTER 18, 19 PERIPHERAL NERVOUS SYSTEM

CHAPTER 13
PERIPHERAL NERVOUS SYSTEM
Functional division of nervous system
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sensory
=
afferent
info to the CNS
ascending spinal cord
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motor
=
efferent
info from CNS
descending spinal cord
somatic
skin , muscles
visceral
organs
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Peripheral nervous system
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nerves outside the CNS
cranial nerves
CNS = brain
• sensory
in to brain
• motor out from brain
spinal nerves
CNS = spinal cord
• sensory
in to spinal cord
• motor out from spinal cord
PNS basic structure
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# neurons between periphery and CNS:
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sensory
receptor to spinal cord - 1 neuron
motor
spinal cord to muscle
- 1 neuron
ANS
CNS to organ
2 neurons
special senses
varies
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ganglia
group of cell bodies outside CNS
usually sensory
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nuclei
group of cell bodies within CNS
motor
location of receptors
exteroceptors
info from environment
interoceptors
info from organs, vessels
proprioceptors
info from joints , muscles
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type of stimulus
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mechanoreceptors
mechanical force
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chemoreceptors
chemical or chemical change
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thermoreceptors
heat
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photoreceptors
light , color
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nociceptors
pain (chemical ?)
structure of receptors
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free nerve endings
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pain, temperature, itch
Merkel – specialized free ending for touch
encapsulated nerve endings
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Meissner, Pacinian, Ruffini
touch and pressure
Proprioceptors
kinesthetic sense
• muscle spindles
• Golgi tendon organ
• joint position
motor endings
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neuromuscular junction
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axon terminal
synapse
motor end plate
motor unit
somatic
skeletal muscle
visceral
smooth , cardiac muscle
Cranial nerves
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peripheral nerves to head and neck
(CN X - to thorax and abdomen)
motor cell bodies
nuclei in brain
sensory cell bodies
cranial sensory ganglia
special sense organs
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axons pass through skull foramen
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numbered I - XII
Cranial nerves
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I
Olfactory
smell
II
Optic
vision
III
Oculomotor
eye movement
IV
Trochlear
eye movement
V
Trigeminal
face sensation
VI
Abducens
eye movement
VII
Facial
face movement
VIII
Vestibulocochlear
hearing; equilibrium
IX
Glossopharyngeal
taste,swallow, BP reflex
X
Vagus
parasympathetic effects
XI
Accessory
trapezius, SCM
XII
Hypoglossal
tongue movement
Cranial nerve I
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CN I
Olfactory nerve
smell
receptors in olfactory epithelium
foramen
???
synapse in olfactory bulb
olfactory tract
Cranial nerve II
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CN II
optic nerve
vision
receptors = retina of the eye
optic nerve through optic canal
crossover at optic chiasma
optic tract to occipital lobe
Cranial nerves - eye movement
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III
Oculomotor
4 extrinsic eye muscles
IV
Trochlear
superior oblique muscle
VI
Abducens
lateral rectus muscle
III
Oculomotor
pupil constriction (ANS)
from midbrain (III and IV) or Pons (VI)
through superior orbital fissure
Cranial nerves - face
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CN V
Trigeminal
sensory to face
motor to masseter, temporalis, pterygoids
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CN VII
Facial
motor to face
sensory - taste
salivary glands (ANS)
lacrimal glands (ANS)
CN V - face sensation
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3 divisions
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face to Pons
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ophthalmic
maxillary
mandibular
V1
V2
V3
V1
supraorbital foramen ;
superior orbital fissure
V2
infraorbital foramen ;
foramen rotundum
V3
mental foramen ;
foramen ovale
CN VII - face movement
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CN VII
Facial
motor
facial muscles
5 branches
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sensory
taste - anterior 2/3 of tongue
chorda tympani
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ANS
parasympathetic to lacrimal glands
and salivary glands (not parotid)
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foramen
internal acoustic meatus
stylomastoid foramen
cranial nerves - ear
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CN VIII Vestibulocochlear
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Cochlear nerve
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hearing
receptors Cochlea
to Medulla ;
to auditory cortex ??
auditory reflex
??
Vestibular nerve
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balance , equilibrium
receptors Vestibule
to Medulla ;
to cerebellum
equilibrium reflex
- Midbrain
internal acoustic meatus
Cranial nerve IX
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CN IX
Glossopharyngeal
=
tongue and pharynx
taste , swallow, saliva , BP
sensory
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taste
BP
carotid sinus
motor
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stylopharyngeus
ANS Parotid gland
jugular foramen
cranial nerve X
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CN X
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medulla through jugular foramen
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Vagus nerve
Parasympathetic
ANS – parasympathetic to most organs
thorax and abdomen
some motor for speech and swallowing
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pharyngeal and laryngeal muscles
cranial nerve – lower muscles
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CN XI
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Accessory
motor to Trapezius muscle
SCM
jugular foramen
CN XII
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Hypoglossal
motor to muscles of tongue
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_______glossus
and suprahyoid group
hypoglossal canal
spinal nerves
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joined spinal roots
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spinal nerve
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31 spinal levels , bilateral
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=
joined spinal roots
C1-8; T1-12; L1-5; S1-5; Coc1
spinal nerve - branches
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rami :
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dorsal ramus
to posterior trunk
ventral
to ventral trunk and limbs
ramus
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peripheral nerves
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back
branches of dorsal rami
C1 – S5
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thorax
branches of ventral rami
T1 – T12
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named branches of rami
peripheral nerves – trunk
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intercostal nerves
abdomen
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branches of ventral rami
T6 – T12
intercostal nerves
nerve plexuses
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a group of spinal nerves
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each peripheral nerve has fibers from a few spinal nerves
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ventral rami
Cervical
C1 - C4
to neck
Brachial
C5 – T1
to upper extremity
Lumbar
L1 – L4
to L/S and LE
Sacral
L4 – S4
to LE and perineum
cervical plexus
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C1 – C4
ventral rami
sensory to skin of neck and occiput
motor to anterior neck muscles
lesser occipital n.
greater auricular n.
transverse cervical n.
phrenic nerve
C3 ,4, 5 diaphragm
brachial plexus
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C5 – T1 spinal nerves
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branch into peripheral nerves to UE
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musculocutaneous n.
median n.
ulnar n.
axillary n.
radial n.
brachial plexus – peripheral nerves
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musculocutaneous n.
motor
sensory
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median n.
motor
sensory
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ulnar n.
motor
sensory
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radial n.
motor
sensory
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axillary n.
motor
sensory
lumbar plexus
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L1 - L4 spinal nerves
to :
anterior thigh
abdominal wall
psoas muscle
peripheral nerves :
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femoral n.
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saphenous n.
obturator n.
motor
sensory
ant. thigh muscles
anter/medial thigh
sensory
medial leg
motor
sensory
adductor muscles
medial thigh
lateral femoral cutaneous n. sensory
lateral thigh
sacral plexus
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L4 - S4 spinal nerves
to:
=
lumbosacral plexus
posterior thigh
lower leg
perineum
peripheral nerves :
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sciatic n.
posterior thigh
entire leg and foot
• tibial n.
posterior leg, plantar area
• common fibular n.
lateral leg, dorsum area
– superficial fibular n.
– deep fibular n.
gluteal nerves
motor to gluteal muscles
dermatomes
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area of skin innervated by a spinal nerve
(sensory)
C1 is motor only
all dermatomes overlap
show embryological development
limb buds from lower neck and L/S areas.
joints
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Hilton’s law : joints innervated by same nerves that innervate the muscles moving that joint