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Anatomy > Nervous System > Flashcards

Nervous System Flashcards

1
Q

nervous system

A

CNS + PNS

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1
Q

CNS

A

brain + spinal cord

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2
Q

brain

A

forebrain
midbrain
hindbrain

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3
Q

PNS

A

cranial nerves
spinal nerves
peripheral ganglia

somatic + autonomic

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4
Q

SNS

A

motor + sensory

control of body wall + upper/lower extremities

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5
Q

ANS

A

visceral
motor + sensory

motor → symp. + parasymp

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6
Q

cells in NS

A

neurons: nerve cells that conduct signals
neuroglia: support cells for neurons

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7
Q

neuron

A

~ 100 billion neurons (10^11)
each one has ~ 100 000 connections with other neurons

cell body = nucleus, nucleolus, dendrites, mitochondria, Nissl bodies
1 axon leaves cell body

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8
Q

synapse

A

connections between neurons
10^15 in CNS

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9
Q

nerve cell bodies

A

nucleus: collection in CNS
ganglia: collection in PNS

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10
Q

Nissl bodies

A

specialized ribosomal bodies
specific to nerve cells

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11
Q

neurofibrils

A

intermediate filament proteins
provide support within axon hillock

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12
Q

axon hillock

A

initial segment
summation of excitatory + inhibitory input
if threshold potential is reached = fires

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13
Q

bipolar neuron

A

2 appendages = 1 dendrite + 1 axon
senses = vision, taste, olfaction

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14
Q

unipolar neuron

A

1 appendage
somatosensation (afferents)

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15
Q

multipolar neuron

A

many dendrites, one axon
efferents (motor)

pyramidal, purkinje, stellate, granule, basket cells → found in brain = different dendrite branching

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16
Q

satellite cells

A

neuroglia that surround cell bodies in ganglia (PNS)
regulate O2, CO2, nutrient, + NT levels around neurons

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17
Q

Schwann cells

A

neuroglia that surround axons in PNS
one cell wraps one section of axon + produces myelin sheath = participate in repair process after injury

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18
Q

oligodendrocytes

A

neuroglia that myelinate CNS axons
have appendages = one cell myelinates many whole axons
provides structural framework

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19
Q

astrocytes

A

neuroglia in CNS
provide structural support; regulate ion, nutrient, + dissolved gas concentrations; absorb + recycle NT; form scar tissue after injury
some maintain blood-brain barrier

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20
Q

ependymal cells

A

neuroglia in CNS
line ventricles + spinal cavity
assist in producing, circulating, and monitoring of CSF

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20
Q

microglia

A

neuroglia in CNS
circulate to remove cell debris, wasts, and pathogens by phagocytosis (substitute for blood = limited by BBB)

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21
Q

meninges

A

membranes covering CNS structures = protection
- dura mater: tough outer layer; protect from external force
- arachnoid mater: secretes CSF into subarachnoid space; covers cranial blood vessels
- pia mater: delicate covering of brain

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22
Q

cerebrum

A

higher cognitive functions
language + speech
somatic motor + sensory function
regulates emotional aspects of behaviour

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23
Q

cerebral cortex

A

outside surface
grey matter
neuronal cell bodies

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24
Q

cerebral medulla

A

inner region
white matter
axons

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25
Q

longitudinal fissure

A

interhemispheric
separates L + R hemispheres

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26
Q

poles of cerebrum

A

frontal pole
occipital pole
2 temporal poles (L+R)

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27
Q

sulci

A

central sulcus = separates pre + post central gyri
lateral sulcus = separates temporal lobe

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28
Q

frontal lobe

A

higher cognitive planning, strategy, motor

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29
Q

parietal lobe

A

perception of self in space, sensory

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30
Q

temporal lobe

A

memory, learning, social, hearing

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31
Q

occipital lobe

A

vision = most important sense

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32
Q

precentral gyrus

A

frontal lobe
primary motor cortex = initiation of motor signals
- motor homunculus - map on cortex corresponding to body
anterior to central sulcus

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33
Q

postcentral gyrus

A

parietal lobe
primary sensory cortex
- sensory homunculus - map on cortex corresponding to body
posterior to central sulcus

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34
Q

projection fibres

A

travel to and from cortex
ex. to/from spinal cord

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35
Q

association fibres

A

intrahemispheric connections
- short ex. within lobe
- long ex. between lobes → BA to WA for speech

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36
Q

commissural fibres

A

interhemispheric connections
ex. corpus callosum = largest

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37
Q

cerebellum

A

acts as a comparator = compares intended movement with evolving movement and corrects for errors → uses feedback to make adjustments
ensures movements are smooth, coordinated, and purposeful (skilled)
regulates posture + balance

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38
Q

cerebellar ataxia

A

intention tremor, lack of balance + coordination

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39
Q

brainstem

A

midbrain, pons, medulla oblongata
contains motor + sensory pathways connecting cerebral cortex + thalamus to SC
houses cranial nerve nuclei (origins of CNs)
contains RAS = arousal + consciousness
vital centres for regulating heart rate + breathing
centres for regulating swallowing + gag reflex

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40
Q

diencephalon

A

thalamus: inferior to corpus callosum; bilateral structure
hypothalamus: inferior to thalamus

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41
Q

midbrain

A

substantia nigra + red nucleus
relay centres for visual and auditory pathways (reflexive orientation)
CNs III + IV attached

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42
Q

substantia nigra

A

regulates motor activity
neuronal degeneration = Parkinson’s disease

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43
Q

red nucleus

A

regulates motor activity
active controller of flexors of upper extremities
controlled by descending inhibition

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44
Q

pons

A

bridge between cerebrum + cerebellum
CNs V, VI, VII, VIII attached

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45
Q

medulla oblongata

A

contains vital cardio-respiratory regulatory centres
nuclei for CNs IX, X, XI, XII

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46
Q

ventricles

A

lumen of neural tube during development
fluid from capillary beds = CSF → circulates within brain

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47
Q

lateral ventricles

A

have anterior + posterior horns
connect to 3rd ventricle

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48
Q

3rd ventricle

A

separates L + R thalamus
feeds into cerebral aqueduct = connects to 4th ventricle

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49
Q

4th ventricle

A

between pons and cerebellum
feeds into central canal within SC

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50
Q

internal carotid arteries

A

paired
ascend carotid canals
divide into anterior + middle cerebral arteries

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51
Q

vertebral arteries

A

branch from subclavian arteries
ascends through foramen magnum
L+R join at pons → basilar artery → posterior cerebral arteries

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52
Q

anterior cerebral artery

A

branches from internal carotid, forms anterior of Circle of Willis
supplies medial + dorsal brain

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53
Q

anterior communicating artery

A

bridges L+R anterior cerebral arteries

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54
Q

middle cerebral artery

A

from internal carotid, extends laterally
supplies lateral brain

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55
Q

posterior cerebral artery

A

from basilar, extends laterally
forms posterior of Circle of Willis
supplies posterior and ventral brain

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56
Q

posterior communicating arteries

A

connects posterior + middle cerebral arteries (2; one on each side)
forms sides of Circle of Willis

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57
Q

spinal cord

A

within vertebral column
projection pathway to/from cerebral cortex; extends from medulla at foramen magnum
ends as conus medullaris at L1-2 intervertebral disc
bulges in lower cervical (brachial plexus) + lumbar (lumbosacral plexus) segments = roots of spinal nerves for upper/lower extremities

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58
Q

central canal

A

within SC; passes through centre of grey matter
continuous with ventricles of brain

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59
Q

cauda equina

A

nerve roots extending from SC; lie inferior
growth to maintain attachment between SC and vertebral column during development (VC grows faster)

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60
Q

filum terminale

A

pia matter continues past SC
attaches cord to coccyx = stabilizing
ends at S2 vertebral level

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61
Q

spinal cord organization

A

inner grey matter
- dorsal (sensory) horn → dorsal root
- ventral (motor) horn → ventral root
outer white matter = axon tracts
dorsal + ventral roots join = spinal nerve

posterior median sulcus; anterior median fissure

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62
Q

sensory + motor info

A

continuous flow between brain, SC, peripheral nerves + organ systems
millions of neurons deliver incoming + outgoing info

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63
Q

pathways between CNS + PNS

A

ascending + descending
consists of a chain of neurons + associated cell bodies (nuclei or ganglia)

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64
Q

somatic sensory pathways

A

dorsal column/medial lemniscal
spinothalamic
spinocerebellar

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65
Q

dorsal columns

A

proprioception + discriminant touch

receptor → 1st order neuron ascends ipsilaterally → medulla = synapse on 2nd order neuron → crosses in brainstem

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66
Q

fasciculus cuneatus

A

upper dorsal column
formed by upper extremities + trunk
corresponds to nucleus cuneatus in midbrain

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67
Q

fasciculus gracilis

A

lower dorsal column
formed by lower extremities + trunk
corresponds to nucleus gracilis in midbrain

68
Q

medial lemniscus

A

2nd order neuron ascends from brainstem through midbrain to thalamus (ipsilaterally)
synapses on 3rd order neuron in ventral nuclei of thalamus

69
Q

thalamocortical projections

A

3rd order neurons project from thalamus to S1 (homotopic = cortex mapped according to receptor region)

70
Q

spinothalamic pathway

A

pain + temp; deep touch

receptor → 1st order neuron enters dorsal horn = synapse on 2nd order neuron → crosses in SC + ascends → thalamus

71
Q

anterior spinothalamic tract

A

deep touch (crude - non-discriminative)
= itch, pressure

2nd order neuron crosses midline of SC from dorsal horn to anterior (white matter)

72
Q

lateral spinothalamic tract

A

pain + temp

2nd order neuron crosses midline of SC from dorsal horn to lateral (white matter)

73
Q

spinocerebellar pathway

A

unconscious proprioception
from trunk + extremities

receptor → 1st order neuron enters dorsal horn = synapses on two 2nd order neurons → anterior + posterior tracts

74
Q

posterior spinocerebellar tract

A

2nd order neuron stays ipsilateral → projects through pons to cerebellum

75
Q

anterior spinocerebellar tract

A

2nd order neuron crosses in SC → projects to pons = crosses over back to ipsilateral pons → cerebellum

76
Q

somatic motor systems

A

CNS sends motor commands → distributed to body by PNS
effect contraction of skeletal muscle
pathways involve at least 2 motor neurons: upper + lower

77
Q

upper motor neuron

A

cell body is in CNS processing centres (M1)
influences LMN: sends descending signal to excitatory/inhibitory synapse

78
Q

lower motor neuron

A

cell body is in ventral horn of SC or motor CN nucleus in brainstem
axon extends to skeletal muscle = Common Final Pathway

79
Q

UMN lesion

A

cannot pass signal
if inhibitory synapse = disinhibition of LMN
= spastic paralysis (continuous, uncontrolled firing leads to rigidity)

80
Q

LMN lesion

A

signal cannot reach periphery
no response = flaccid paralysis → tone cannot be monitored (no feedback)

81
Q

motor pathways

A

corticospinal pathway (pyramidal)
corticonuclear pathway (corticobulbar)

82
Q

corticospinal pathway

A

UMNs descend from cerebral cortex (M1 + S1) through crus cerebri (midbrain) and pyramids (anterior medulla) → SC
= synapse on LMN in ventral horn (somatic motor nuclei) → muscles in limbs + trunk

bundle of fibres (~1m) originating from pyramidal neurons in cortex from 3 main areas: M1, PMC + SMA, S1
regulates distal limb muscles → precise, skilled, learned movements

83
Q

corticonuclear pathway

A

UMNs extend from cerebral cortex (M1) → motor CN nuclei in brainstem
= synapse on LMN → head + neck muscles

84
Q

extrapyramidal pathways

A

subsidiary descending pathways
important as backup systems

85
Q

basal ganglia + cerebellum pathways

A

modulate + modify activity in corticospinal tract to ensure smooth, coordinated, purposeful movement

86
Q

central motor program

A

production of voluntary movements
- incoming sensory info is conveyed to posterior parietal cortex via association fibres
- posterior parietal cortex = process info to identify + localize targets in space
- PMC + SMA = formulation of plan of action
- M1 = execution of movement through desc pathways

87
Q

simple finger flexion

A

activates:
- M1 = effect movement
- S1 = receive feedback about movement

88
Q

finger movement sequence (performance)

A

activates:
- M1 + S1
- premotor + supplementary motor area = activity prior to movement + during (planning sequence)

89
Q

finger movement sequence (mental rehearsal)

A

activates:
- only premotor + supplementary motor area

90
Q

lateral corticospinal pathway

A

85% of UMN axons cross at pyramids in inferior medulla = contralateral path to SC

91
Q

anterior corticospinal pathway

A

15% of UMN axons stay ipsilateral at pyramids in medulla
cross midline in SC (at level they leave to periphery)

92
Q

internal capsule

A

area of bundled axons of corticospinal path in brain
supplied by small arteries

93
Q

UMN lesion ex. corticospinal pathway

A
  • middle cerebral artery stroke or injury to internal capsule = lose all corticospinal input
  • brainstem lesion = decorticate or decerebrate posture
  • spinal cord injury = lose UMN output

= spastic paralysis in contralateral limb

94
Q

decorticate posture

A

no inhibitory control of upper extremity muscles = flexion
lesion above level of red nucleus
stiff, legs out straight, arms flexed across chest

95
Q

decerebrate posture

A

inhibitory control is present to prevent flexion = extensor muscles are active
lesion below level of red nucleus
all limbs extended and held stiff

96
Q

LMN lesion ex. corticospinal pathway

A

spinal nerve injury → lost downstream flow
= flaccid paralysis

97
Q

SNS

A

supplies body wall structures (skin, muscle, bone, parietal membranes)
motor functions: skeletal muscle = voluntary control (exception: reflex arc)
sensory functions: pain, temp, touch, proprioception

98
Q

ANS

A

supplies viscera (glands, smooth muscle, cardiac muscle, visceral membranes) → involuntary control
motor functions: symp + parasym → balance
sensory functions: visceral afferents → pain (indirect or referred)

99
Q

spinal nerves

A

emerge from SC → out to periphery = supply peripheral structures
31 pairs: 8C, 12T, 5L, 5S, 1C

dorsal + ventral root together
bifurcates into ventral + dorsal primary rami (end of SN)

100
Q

cervical spinal nerves

A

nerve emerges superior to respective vertebrae (C8 n. = inferior to C7 vertebrae)
all downstream nerves (T-Coccygeal) emerge inferior to respective vertebrae

101
Q

general afferents

A

carry sensory info to SC
- somatic afferents (GSA) = PTTP from body wall
- visceral afferents (GVA) = pain, distention, chemical from visceral structures

102
Q

general efferents

A

emerge from SC + carry motor info away
- somatic efferents (GSE) = motor neurons in ventral horn projecting to skeletal muscles
- visceral efferents (GVE) = autonomic fibres innervating smooth muscle, cardiac muscle, glands

103
Q

intermediate zone

A

lateral horn (grey matter) in sc at levels T1-L2 = symp. preG cell bodies
autonomic

104
Q

dorsal primary ramus

A

feeds through muscle
supply muscle + reach subcutaneous space → posterior cutaneous branch = sensation to skin
only back (stops at scapula)

105
Q

ventral primary ramus

A

continues all around body wall
lies between muscles that form wall
supplies all body wall muscle (all plexi)
lateral cutaneous branch: formed by branching at mid-axillary line
anterior cutaneous branch: formed by branching at midline

106
Q

dermatome

A

innervation of entire strip of skin around body wall by spinal nerve
= segmented pattern along body (on all 4s)
VPR follows extremities

T4 = nipples
T10 = umbilicus

107
Q

intervertebral foramen

A

opening between vertebrae
where spinal nerve emerges

108
Q

vertebral canal

A

down middle of spinal column
where spinal cord is

109
Q

nerve

A

covered by epineurium
contains fascicles + blood vessels

grow slowly

110
Q

fascicles

A

bundle of axons going to area of body
individually covered by perineurium (membrane)

111
Q

nerve axons

A

covered by endoneurium = integrity
make up fascicles

112
Q

reflex arc

A

short circuit information pathway
1. stimulus = activation of receptor
2. activation of sensory neuron
3. info processing in CNS (interneuron)
4. activation of motor neuron
5. response by effector

info still travels to brain

113
Q

somatic nerve plexuses

A

formed by ventral spinal rami
- at thoracic level → follows ribs
- above + below thoracic → nerves aggregate to form plexus

114
Q

brachial plexus

A

supplies upper extremities

VPR of SNs C5, C6, C7, C8, T1
→ 5 main nerves: axillary, median, musculocutaneous, radial, ulnar

115
Q

lumbar plexus

A

lower anterior abdominal wall
medial + anterior thigh
inguinal region (groin)

VPR of SNs L1, L2, L3, L4
→ 6 main nerves: iliohypogastric, ilioinguinal, genitofemoral, lateral femoral cutaneous, femoral, obturator

116
Q

cremasteric reflex arc

A

formed by ilioinguinal + genitofemoral nerves
(lumbar plexus)

117
Q

lumbosacral plexus

A

gluteal region
lower extremities (except ant. med. thigh)
perineal region + genitals

VPR of SNs L4, L5, S1, S2, S3
→ 6 main nerves: tibial, common peroneal, superior gluteal, inferior gluteal, pudendal, posterior femoral cutaneous

118
Q

autonomic motor system

A

controlled by hypothalamus → output to pons + medulla
neurons synapse in periphery before target site (next to vertebral column) = 2 neuron system
- preG fibre: from CNS → autonomic ganglion
- postG fibre: from ganglion → effector site

119
Q

sympathetic autonomic motor nerves

A

GVEs
thoracolumbar (SC levels)
T1-L2 (lateral horn in grey matter = symp preG nerve cell bodies → synapse in symp ganglion on post G fibre)
fight or flight + fright

120
Q

parasympathetic autonomic motor nerves

A

GVEs
craniosacral
- CN III, VII, IX, X
- S2, S3, S4
preG neurons extend from CNS to ganglion near target
rest, relax, regenerate

121
Q

sympathetic NS

A

SNs (T1-L2)→ symp. ganglia → symp. nerves → targets

122
Q

sympathetic chain ganglia

A

secondary pathway
collection of ganglia linked together by axons passing between
distribute symp. info up + down for postG supply to supradiaphragmatic organs
break at T5

123
Q

splanchnic nerve

A

preG fibres pass through symp. ganglia without synapsing and join to form nerve
nerve extends to prevertebral ganglia = close to visceral targets → synapse with postG fibres

supply visceral organs (subdiaphragmatic)

124
Q

sympathetic actions

A

eye: pupil dilation
salivary glands: thick viscid secretion
trachea + bronchioles: dilation
heart: ↑ rate + contractility
ureters + bladder: relax detrusor m. (wall of bladder) + contract trigone + sphincter
gastrointestinal: ↓ motility + tone; contract sphincter
genitalia: ejaculation + relaxation of uterus
blood vessels: dilation in skeletal muscle; constriction in viscera

125
Q

parasympathetic NS

A

no control to the skin
CNs III, VII, IX, X → preG to terminal ganglia = synapse on postG → targets
pelvic splanchnic nerves → preG to targets = synapse on postG → effect

126
Q

parasympathetic actions

A

eye: pupil constriction; accomodation reflex
lacrimal gland: stimulate tears
salivary glands: copious watery secretion
trachea + bronchioles: constrict; ↑ secretion
heart: ↓ rate + contractility
ureters + bladder: contract detrusor m.; relax trigone + sphincter
gastrointestinal: ↑ motility + tone
genitalia: stimulates erection

127
Q

subcutaneous structures

A

supply to skin
from SN, enters symp. chain via white ramus → synapse on postG → leave through grey ramus back to SN

128
Q

supradiaphragmatic organs

A

preG lateral horn (T1-T5)
ventral root → SN → ganglion → up/down symp. chain
synapse on different postG → goes straight to organ
- heart = cardiac nerve
- lungs = pulmonary nerve

129
Q

subdiaphragmatic organs

A

preG fibre leaves SN via white ramus to ganglion but doesn’t synapse → pass through symp. ganglion = forms splanchic nerves
→ synapse in prevertebral (collateral) ganglion associated with abdominal aorta where branch comes off
postG follows blood vessel

130
Q

general visceral afferents

A

autonomic sensory info
follows same pathway as motor info
ex. splanchic n. → symp. ganglion → white ramus → SN → dorsal root ganglion

131
Q

referred pain

A

pain in visceral structures → referred to body wall through dermatomes
ex. appendix
- T10 symp. level → swelling = interpreted as pain at T10

132
Q

cranial nerves

A

emerge from area of brainstem
12 pairs
(exception of X) run functions of head + neck
arise from + interact with nuclei in brainstem
cell bodies of sensory neurons = in CN ganglia

133
Q

CN I

A

olfactory nerve
pure sensory = olfaction

134
Q

olfactory nerve path

A

receptors on roof of nasal cavity → olf. epithelium = supplied by olf. nerve filaments → pass through cribiform plate, terminate in olf. bulb → olf. tract → primary olf. cortex in temporal lobe (bypass thalamus)

135
Q

damage to olfactory nerve

A

hyposmia / anosmia = ↓ sense of smell

135
Q

CN II

A

optic nerve
pure sensory = vision

136
Q

optic nerve path

A

retinal receptors → bipolar → amacrine → ganglion cells = axons → optic nerve
optic nerve → optic chiasm → tract → LGN → V1

VFs projected onto V1 inverted + reversed
V1 = medial occipital, along calcarine fissure

137
Q

damage to optic nerve

A

visual field defects

138
Q

CN III

A

oculomotor nerve
from midbrain
mixed nerve
- somatic motor → extraocular muscles
- parasymp. → pupillary constriction + accomodation (ciliary ganglion)

139
Q

oculomotor nerve path

A

superior division:
- superior rectus + levator palpebrae mm.

inferior division:
- medial rectus + inferior rectus + inferior oblique mm.
- carries preG parasymp. info to ciliary ganglion → pupillary constrictor + ciliary + medial rectus mm.

140
Q

damage to oculomotor nerve

A

pupillary dilation
ophthalmoplegia (weakened eye movements)

141
Q

CN IV

A

trochlear nerve
from midbrain (posterior)
smallest CN; longest intracranial path
pure motor = superior oblique m.

142
Q

damage to trochlear nerve

A

isolated = uncommon
protected by double layer of dura

143
Q

CN VI

A

abducens nerve
pure motor = lateral rectus m. (abduction of eye)
at ponto-medullary junction (anterior surface of pons)

144
Q

damage to abducens nerve

A

vulnerable to injury in head trauma/ ↑ intracranial pressure
damage = paralysis of muscle → deviation of eye medially (strabismus) = double vision (diplopia)

145
Q

CN V

A

trigeminal nerve
chief sensory nerve to face
3 branches from trigeminal ganglion
mixed nerve = sensory + motor
conduit for parasymp. functions of CNs III, VII, IX

146
Q

damage to trigeminal nerve

A

mainly V2, V3
trigeminal neuralgia (tic Douloureux)
very painful

147
Q

V1

A

ophthalmic nerve
eye = pure sensory
→ supraorbital nerves
ciliary ganglion = parasymp. relay from CN III

supplies superior corner of eye towards lambdic suture
sensation to frontal + ethmoidal paranasal air sinuses
sensory innervation (general sensation) to nasal cavity
sensation to upper eyelid, side of nose, forehead + scalp

148
Q

V2

A

maxillary nerve
cheek = pure sensory
→ infraorbital nerves
pterygopalatine ganglion = parasymp. relay for CN VII

enters floor of orbit through inferior orbital fissure
supplies corner of eye to corner of mouth
sensation to: maxillary air sinus, nasal cavity, lower eyelid, skin of cheek, upper lip, maxillary teeth + gums

149
Q

V3

A

mandibular nerve
mandible

somatic motor:
→ muscles of mastication
sensory:
→ lingual nerve (submandibular ganglion = CN VII)
→ inferior alveolar nerve → mental nerve
otic ganglion = parasymp. relay for CN IX

150
Q

V3 functions

A

motor
- muscles of mastication (4)
sensory
- lower lip, skin of mandible
- mandibular teeth + gums (i.a. n.)
- general sensation to anterior 2/3 of tongue (l. n.)
- ends as mental n.
- carries proprioceptive info from muscles of mastication to brainstem = force of bite

151
Q

CN VII

A

facial nerve
mixed nerve = somatic motor + sensory, parasympathetic
attached to pons
geniculate ganglion

152
Q

facial nerve path

A

pons → geniculate ganglion
- main branch = 5 → muscles of facial expression
(temporal, zygomatic, buccal, mandibular, and cervical branches)
- chorda tympani n. → submandibular ganglion
- posterior auricular n.
- greater petrosal n. → pterygopalatine ganglion

153
Q

damage to facial nerve

A

partial taste, salivation, or lacrimation loss
Bell’s palsy = hemi-facial paralysis

154
Q

facial nerve functions

A

motor
- muscles of facial expression (5 branches)
sensory
- taste to anterior 2/3 of tongue (chorda tympani n.)
- some sensory to skin around ear
parasympathetic
- lacrimal gland via pterygopalatine (V2)
- submandibular + sublingual salivary glands via submandibular ganglion (V3)

155
Q

CN VIII

A

vestibulocochlear nerve
pure sensory
- cochlear branch → organ of Corti
- vestibular branch → vestibular apparatus

156
Q

vestibular branch CN VIII

A

supplies vestibular apparatus (semicircular canals + vestibule)
= balance and equilibrium

disease: Meniere’s syndrome (vertigo, nausea, vomiting)

157
Q

cochlear branch CN VIII

A

supplies organ of Corti in cochlear = hearing
bilateral central pathway in brainstem carries info to temporal lobe → primary auditory cortex

damage: difficulty in localizing sound

158
Q

CN IX

A

glossopharyngeal nerve
mixed nerve = somatic motor + sensory, parasympathetic
attached to medulla
supplies tongue + pharynx; mediated gag reflex

main branch → carotid sinus + pharyngeal branches + lingual branches
branch → otic ganglion → parotid gland

159
Q

damage to glossopharyngeal nerve

A

difficulty swallowing, loss of gag reflex (protection of airway)

160
Q

glossopharyngeal nerve functions

A

motor
- one muscle = stylopharyngeus (elevates pharynx) through lingual branch
sensory (general)
- posterior tongue, pharynx, palatine tonsils, carotid sinus + body
sensory (special)
- taste to posterior 1/3 of tongue
parasympathetic
- supplies parotid gland via otic ganglion (V3)

161
Q

carotid sinus reflex

A

carotid stimulation
= induce response to ↓ bp and pulse rate

monitors bp + blood chemistry → feedback

162
Q

CN X

A

vagus nerve
mixed nerve = motor, sensory, parasymp.
attached to medulla

damage: difficulty in speech + swallowing

163
Q

vagus nerve functions

A

motor
- muscles of palate, pharynx, larynx (CN XI)

sensory
- muscles of palate, pharynx, larynx
- sensory to eardrum
- baroreceptor to hollow organs
- carries visceral afferents from organs to CNS

parasymp.
- nerve for viscera
- motor to smooth muscle in thoracic + abdominal organs up to distal transverse colon
- regulates heart rate (↓)

164
Q

CN XI

A

spinal accessory nerve
motor only
attached to medulla + upper SC

damage = weakness when shrugging shoulders, turning head to side against resistance

165
Q

cranial - spinal accessory nerve

A

extends from accessory root → accessory branch
distributed by CN X to palate, pharynx, larynx
(CN X sensory functions)

166
Q

spinal - spinal accessory nerve

A

extends from spinal root → spinal branch
supplies trapezius and sternocleidomastoid muscles in neck

167
Q

CN XII

A

hypoglossal nerve
pure motor
attached to medulla
supplies muscles of tongue (except stylopharyngeus)

damage: inability to protrude tongue symmetrically

168
Q
A

Anatomy (14 decks)

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