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Anatomy 101 > chapter 16 - brain and cranial nerves > Flashcards

chapter 16 - brain and cranial nerves Flashcards

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1
Q

• brain consists of

A

the brainstem (medulla oblongata, pons, mesencephalon), cerebellum, diencephalon (epithalamus, thalamus, hypothalamus), and cerebrum

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2
Q

• cortex

A

= grey matter located on the surface of the cerebrum and cerebellum

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3
Q

• nuclei

A

deep clusters of grey matter surrounded by white matter

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4
Q

• extremely delicate – requires protection provided by:

A

o bony skull
o cranial meninges
o cerebrospinal fluid
o blood-brain barrier

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5
Q

Ventricles

A

• cavities and tubes lined with ependymal cells and filled with cerebrospinal fluid

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6
Q

• lateral ventricles

A

relatively large cavities – one within each hemisphere of cerebrum
o connected to third ventricle by interventricular foramen

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7
Q

• third ventricle

A

small cavity in center of diencephalon between two halves of thalamus

o cerebral aqueduct – slender canal that passes through mesencephalon and connects third ventricle to fourth ventricle

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8
Q

• fourth ventricle

A

= begins between pons and cerebellum to superior portion of medulla oblongata
o continuous with subarachnoid space
o inferior part of medulla oblongata narrows and continues into spinal cord as central canal

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9
Q

• hydrocephalus

A

blockage of cerebral aqueduct or fourth ventricle
o blocked at time of birth or due to encephalitis (brain infection), meningitis (infection of meninges covering brain), trauma, and tumors affecting brainstem
o production of CSF continues but blocked exits cause increased intracranial pressure
 if skull bones not completely ossified – pressure may severely enlarge the head
 compresses blood vessels, dilates ventricles and compresses of nervous tissue resulting in irreversible brain damage
o treated successfully by placing shunt (drainage tube) between ventricles and abdominal cavity

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10
Q

Cranial Meninges

A

surround brain and continuous with spinal meninges
• epithelial and connective tissue membranes that protect brain – acting as shock absorbers and preventing contact with skull bones

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11
Q

• dura mater

A

dense irregular fibrous connective tissue
o thickest and most superficial
o two layers - adhere tightly to cranial bones
 periosteal cranial dura = outermost layer – fused to periosteum of cranial bones
 meningeal cranial dura = inner layer that is continuous with dura mater of spinal cord

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12
Q

o dural sinuses

A

= spaces formed where two layers of dura mater are separated from each other
 lined with endothelium and transport venous blood and cerebrospinal fluid
 all veins draining blood from brain empty in dural sinuses that then drain into internal jugular veins

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13
Q

o meningeal cranial dural folds

A

partitions that extend into major brain fissures
 falx cerebri (Fig 16.3, 16.5) = lies within longitudinal fissure and anchors anteriorly to crista galla of ethmoid bone

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14
Q

o subdural space

A

between opposing epithelial of dura and arachnoid mater and contains small amount of serous fluid

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15
Q

• arachnoid mater

A

middle thin and wispy layer
o subarachnoid space (Fig 16.5) = network of collagen and elastin fibers between arachnoid and pia maters
 contains blood vessels and cerebrospinal fluid

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16
Q

• pia mater

A

deepest layer tightly bound to surface of brain

o anchored to surface of brain by processes of astrocytes

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17
Q

Cerebral Spinal Fluid (CSF

A
  • clear fluid similar to blood serum with most of proteins removed
  • provides protective cushion around CNS and allows brain to float within cranial cavity
  • provides some nutrients to CNS tissues
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18
Q

cerebral spinal fluid produce by ?

A

choroid plexus : specialized ependymal cells, support tissue and capillaries
o formed by invaginations of pia mater into roof of ventricles and covered by ependymal (special epithelial) cells
o ependymal cells secrete Na+ into ventricles and water follows by osmosis
o tight junctions between cells forming barrier
 substances do not pass between cells but must be transported across cells

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19
Q

cerebral spinal fluid fills…

A

• fills ventricles, subarachnoid space and central canal of spinal cord (Fig 16.7)
o some drains into dura sinuses to be removed by venous circulation

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20
Q

blood supply to brain

A
  • brain has high metabolic rate and brain neurons not capable of storing high-energy molecules (glycogen)
  • requires large, constant blood flow for oxygen and glucose delivery
  • receives 15-20% of blood pumped by heart
  • interruption of blood flow for seconds can cause unconsciousness – for minutes = irreversible brain damage
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21
Q

blood supply to brain via :

A

o internal carotid arteries (Fig 22.12) – enter via carotid canals (temporal bones)
o vertebral arteries – enter via foramen magnum
 join to form basilar artery
o cerebral arterial circle (Circle of Willis) (Fig 22.13) = contributions from basilar artery and internal carotid arteries
 anterior, middle and posterior cerebral arteries = branches that supply cortex

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22
Q

what is a brainstem ?

A

• connects the spinal cord to the brain
• contains three anatomical subdivisions (inferior to superior):
o medulla oblongata, pons, and mesencephalon (midbrain)
• and one functional unit – the reticular formation that spans all three anatomical divisions
• contains many reflex centers essential for survival

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23
Q

medulla oblongata

A

most inferior (caudal) portion of brain
o contains sensory and motor tracts
 pyramids – prominent enlargements on anterior surface
• contain large descending motor tracts controlling skeletal muscle

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24
Q

cranial nerve nuclei

A

= clusters of grey matter composed mostly of neuron cell bodies

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25
Q

olivary nuclei

A

– protrude from anterior surface lateral and superior to pyramids
• nuclei involved in balance, coordination, and modulation of sound from inner ear
• relays information to the cerebellar cortex

part of cranial nerve nuclei

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26
Q

brainstem stem serve as

A

 serve as centers for vital reflexes
• cardiovascular centers – regulating heart rate and blood vessel diameter
• respiratory centers – rate and depth of breathing, coughing, sneezing

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27
Q

nuclei for cranial nerves

A

VIIl, IX, X, XI, and XII

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28
Q

• pons

A

– connects brainstem to the cerebellum by cerebellar peduncles
o nuclei for cranial nerves V, VI, VII and VIII
o sleep center that initiates REM (rapid eye movement) sleep

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29
Q

• mesencephalon

A

contains nuclei for cranial nerves III, and IV

o four sensory nuclei form mounds on dorsal surface = corpora quadrigemina

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30
Q

 superior colliculi

A

– receive sensory input from visual, auditory and tactile sensory systems
• involved in reflex movements of head, eyes and body toward stimulus
o “startle reflex”, loud noise, bright light, acute pain

part of mesencephalon

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31
Q

 inferior colliculi

A

– involved in hearing

part of mesencephalon

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32
Q

o red nucleus

A

(appears pink due to blood flow) aids in unconscious regulation and coordination of motor activities

part of mesencephalon

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33
Q

o substantia nigra

A

appears dark due to melanin granules) part of the basal nuclei system
 involved in maintaining muscle tone and coordinating movement

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34
Q

• reticular formation

A

diffuse system of nuclei scattered throughout length of brainstem
o receives axons from large number of sources
o modulates and controls many functions of the brainstem
o controls state of alertness and consciousness – including sleep-wake cycle

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35
Q

Cerebellum

A

• three parts:
o cerebellar hemispheres (2) – participates with cerebral cortex to plan, practice, smooth and coordinate limb and trunk movements
 divided by primary fissure into anterior and posterior lobes
o vermis = narrow central portion
 together with medial portion of hemispheres control posture, and allow smooth flowing movements
o flocculonodular lobe = small lobe – lies inferior and anterior to hemispheres – helps control balance and eye movements

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36
Q

• grey matter- cerebellum

A

o on cortex (surface) – has ridges called folia
 contains several cell types (neurons): stellate, basket, granule, Golgi, and Purkinje
• Purkinje cells – largest, inhibitory and only cortical neurons that send axons to the cerebellar nuclei
 mossy fibers = afferent axons that branch extensively within cerebellum
o and in deep cerebellar nuclei surrounded by white matter

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37
Q

• white matter

location

A

in medulla – resembles branching tree = arbor vitae

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38
Q

• cerebellar peduncles

A

) link the cerebellum to the posterior portion of the brainstem

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39
Q

• ataxia

A

= loss of muscle coordination in the arms or legs due to cerebellar dysfunction

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40
Q

Diencephalon

A
  • between brainstem and cerebrum

* contains: epithalamus, thalamus, and hypothalamus

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41
Q

• epithalamus

A

roof of third ventricle and is superior and posterior to thalamus
o contains: pineal gland – secretes melatonin
 action not completely understood – modulation of biorhythms and sleep-wake cycle

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42
Q

• thalamus

A

largest part with two lateral portions connected in center

o surrounds third ventricle of brain

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43
Q

o receives all sensory input

A

 synapse in thalamus then relayed to appropriate areas of cerebral cortex (Table 16.5)
 anterior nuclei – part of limbic system – role in emotions, memory and learning
 medial nuclei – provide conscious awareness of emotional states
 ventral nuclei
• ventral lateral and ventral anterior relay information to and from basal nuclei, cerebellum and cerebral cortex that allow formation and fine tuning of movement plans

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44
Q

• ventral posterior

A

relays touch, pain, temperature and proprioceptive information to the primary somatosensory cortex of the parietal lobe

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45
Q

 posterior nuclei

A

– contains two sets of nuclei: pulvinar and geniculate nuclei
• pulvinar nuclei – project sensory input to association areas of the cerebral cortex
• medial geniculate nucleus – receives auditory information
• lateral geniculate nucleus – receives visual information

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46
Q

 lateral nuclei

A

feedback loop relay stations with impact on emotional states and integration of sensory information

47
Q

• hypothalamus

A

most inferior portion (Fig 16.12, Table 16.6)

o floor of 3rd ventricle – area superior to optic chiasm to posterior margin of mammillary bodies

48
Q

 mammillary bodies

A

= bulges on ventral surface – part of limbic system and recollective memory
• involved in olfactory and feeding reflexes and emotional responses to odors

49
Q

o infundibulum

A

stalk containing blood vessels and axons and connects to pituitary gland
o contains several nuclei and tracts
 receives sensory input from cerebrum, brain stem and spinal cord
o responds to humoral stimuli – changes in:
 CSF and interstitial fluid composition
 circulating blood due to high permeability of capillaries in this region

50
Q

infundibulum

o responds to humoral stimuli – changes in:

A

 CSF and interstitial fluid composition

 circulating blood due to high permeability of capillaries in this region

51
Q

o major functions associated with nuclei

infundibulum

A

 central controller of endocrine system
• supra-optic and paraventricular nuclei release hormones that have direct effects on tissues
• tuberal nuclei release hormones that control release of hormones from the pituitary gland
 major coordinator of autonomic nervous system
 temperature regulation and shivering reflex
 food and water intake – hunger, thirst and satiety centers, swallowing reflex
 emotions – center of limbic system – directly involved in stress-related and psychosomatic illnesses and in feelings of fear and rage
 sleep-wake cycle
 sexual development and behaviour

52
Q

Cerebrum

A
  • largest portion of the brain and size related to body size
  • provides conscious thought, awareness of sensory information and all intellectual functions
  • control conscious (voluntary) motor output
53
Q

Cerebrum

• longitudinal fissure

A

separates cerebrum into right and left hemispheres

54
Q

• gyri =

A

folds (ridges) on cerebral cortex – increases surface area

55
Q

• sulci

A

= grooves between gyri

56
Q

• each hemisphere divided into lobes named for overlying skull bones

Cerebrum

A

o frontal lobe – voluntary motor function, motivation, aggression, sensation of smell, mood, personality and decision making
 central sulcus – extends laterally across cerebrum separating frontal from parietal lobes
• precentral gyrus = ridge anterior to central sulcus – contains primary motor cortex (Fig 16.17)
• postcentral gyrus = ridge posterior to central sulcus – contains primary somatosensory cortex
o receives somatic sensory information – touch, pressure, pain, taste and temperature from dorsal column and spinothalamic tracts

57
Q

o parietal lobe

Cerebrum

A

sensory information

 parieto-occipital sulcus – separates parietal lobe from occipital lobe

58
Q

o occipital lobe

Cerebrum

A

visual information

59
Q

o temporal lobe

Cerebrum

A

– smell and hearing and important role in memory
 lateral sulcus – separates temporal lobe from rest of cerebrum
 insula – island deep within lateral sulcus – taste information

60
Q

• grey matter

Cerebrum

A

o cerebral cortex – ranges from 2 to 6 layers thick
 fusiform cells, stellate cells and pyramidal cells
• pyramidal cells = neurons associated with motor cortex and relay voluntary movement information to somatic motor neurons in brain stem and spinal cord

61
Q

o integrative regions

grey matter on cerebrum

A

– integrate complex sensory stimuli and motor responses
 prefrontal cortex – very complex - extensive connections with other areas of the cortex
• complicated learning and reasoning functions
• emotional context and motivation
• predicts future consequences of actions - associated with feeling of frustration, tension and anxiety

62
Q

o prefrontal lobotomy

A

until mid-twentieth century = removal of area to treat mental illnesses especially those associated with violent or antisocial behaviour
 damage results in difficulty estimating temporal relationship between events (“How long ago did this happen?”, “What happened first?”)

63
Q

 hemispheric lateralization

A

= certain integrative regions present in only one hemisphere

64
Q

• categorical or dominant hemisphere

A

usually left hemisphere containing speech center and language interpretation center
o usually determines handedness – right-handed actions directed from left hemisphere of brain
o important in performing analytical skills – math and logic

65
Q

• aphasia

A

condition arising from damage to area associated with language
o affects ability to interpret what is read or heard even though individual words or entities are understood – e.g. “sit” and “here” but not “sit here”
o extreme aphasia – unable to speak or read or understand or interpret speech of others
o recovery possible when condition results from edema or hemorrhage – take months to years

66
Q

 Wernicke’s area

A

near the auditory cortex

• associated with language comprehension and aids in coordinating access to visual and auditory memories

67
Q

 speech center (Broca’s area

A

along edge of pre-motor cortex on same side as general interpretive center
• associated with speech production
• regulates patterns of breathing and vocalization needed for speech
• coordinates muscles of tongue, cheeks, lips and jaws
• damage to area – person can make sounds but not words

68
Q

dyslexia

A

disorder affecting comprehension of written words

  • developmental dyslexia affects up to 15% of US children – difficulty reading and writing but other intellectual functions normal or above normal
  • some forms result from problems processing and sorting visual information
69
Q

 representational or non-dominant hemisphere

A

right hemisphere – allows spatial perception, recognition of faces, emotional context of language, appreciation of art and music
• interpretive centers permit identification of familiar objects by touch, smell, taste or feel
• only 9% of human population is left-handed actions – controlled by right primary motor cortex but still have language centers on left side of brain
o high percentage of musicians and artists are left-handed

70
Q

nuclei

A

– deep within the medulla (middle of the cerebrum)

71
Q

 Alzheimer’s Disease

A

chronic progressive illness characterized by memory loss and impairment of higher-order cerebral functions – abstract thinking, judgement and personality
• associated with senile dementia – with 50% over age 85 having some form of the condition

• neurofibrillary tangles and plaques in regions associated with memory processing
o nucleus basalis, hippocampus, parahippocampal gyrus
• loss of memory affects both intellectual and motor abilities – develop pronounced decrease in number of cortical neurons in frontal and temporal lobes
• no cure but progression can be slowed by:
o medications and supplements (antioxidants, B vitamins), and mental and physical activity

72
Q

• white matter

A

in cerebral medulla and contains tracts that connect areas of the cerebral cortex
o association fibers – connect areas of cerebral cortex within same hemisphere
o commissural fibers – connect one cerebral hemisphere to the other
 corpus callosum = largest bundle
o projection fibers – connects cerebrum to other parts of brain and spinal cord – form internal capsule

73
Q

Basal Nuclei

A

• group of functionally related nuclei located bilaterally in inferior cerebrum that interact with nuclei in the diencephalon, and mesencephalon
• involved in planning of movement and pattern generation:
o subconscious control and integration of skeletal muscle tone
o coordination of learned movement patterns

74
Q

• caudate nucleus

A

large head and thinner tails - follows curve of lateral ventricle

75
Q

• lentiform nucleus

A

– medially located between insula and lateral wall of diencephalon subdivided into:
o putamen – laterally located
 together with caudate nucleus – control cycle of arm and leg movements between the initiation and end of a walking movement pattern

76
Q

o globus pallidus

A

medially located – controls and adjusts muscle tone to set body position in preparation for a voluntary movement

77
Q

• subthalamic nucleus

A

– in diencephalon

78
Q

• substantia nigra

A

in mesencephalon releases dopamine – acts on basal nuclei to suppress excitatory motor output

79
Q

o Parkinson’s Disease

A

= motor symptoms resulting from a lack of dopamine release from substantia nigra
 increased muscle tone, difficulty initiating movement, spasticity - hesitant and jerky voluntary movement, continual resting tremor, automatic positioning and preparatory adjustments no longer occur – resulting in balance problems
 treatment with L-Dopa (crosses blood-brain barrier and can be converted to dopamine, surgery, transplantation of fetal brain cells

80
Q

Limbic System

A
  • central role in basic survival functions and behavioural drives, and interpreting sensory input and emotions, facilitating memory storage and retrieval
  • deep portions of the cerebrum that form a ring around the diencephalon
  • parts of cerebrum, diencephalon and mesencephalon
81
Q

limbic role

A

= cerebral cortical areas and deep nuclei
o cingulate gyrus (inner surface of longitudinal fissure – superior to corpus callosum)
o parahippocampal gyrus (medial side of temporal lobe)
o dentate gyrus
o hippocampus – nucleus deep within temporal lobe
o amygdala (part of basal nuclei)

82
Q

• fornix

A

= tract of white matter – connects the hippocampus to thalamus and mammillary bodies of hypothalamus

83
Q

• open head injuries

A

= cranial contents exposed to outside (brain, blood and/or CSF)
o injuries involving scalp lacerations or damage to the eye, ear or nose should be carefully evaluated for possibility of open head injury
o in skull fractures in which meninges torn – CSF may leak from nose if fracture in frontal area, or the ear if fracture is in the temporal area

84
Q

• closed head injuries

A

cranial cavity remains intact
o more common resulting from head striking hard surface or object striking head resulting in brain trauma
 coup = brain injury at site of impact
 contrecoup = brain injury occurring on opposite side of brain from the impact as a result of the brain moving within the skull

85
Q

o concussion

A

mild TBI usually accompanied by a period of unconsciousness
 minor = immediate but transient impairment of neural function – loss of consciousness, blurred vision, some degree of amnesia
 severe = extended periods of unconsciousness and abnormal neurological function – vomiting, convulsions or seizures, slurred speech, weakness, numbness in arms and legs, dilated pupils
• associated with contusions (bruises), hemorrhages, or lacerations (tears) of the brain tissue
 treatment – rest and avoid further trauma

86
Q

• diffuse brain injury

A

– results from shaking (“shaken baby syndrome”) or car accidents (“whip-lash”)
o damage to many small blood vessels and nerves especially around brainstem

87
Q

• chronic traumatic encephalopathy (CTE)

A

results from repeated sports-related head trauma
o boxers, football, soccer
o prevalence unknown and no cure

88
Q

• hemorrhagic brain injury

A

involves hemorrhage (bleeding) and accumulation of blood – hematoma

89
Q

o epidural hemorrhage

A

(hematoma) = outside the dura (~1% major head injuries)
 tear of middle meningeal artery, vein, or dural sinus in middle portion of cranial cavity
 pressure of blood distorts underlying soft tissues of brain
 individual losses consciousness from minutes to hours after injury and death follows if untreated
 treatment = drilling hole in skull allowing blood to drain

90
Q

o subdural hemorrhage

A

– more common (up to 10% of major head injuries)
 tears in cortical veins or dural venous sinuses in superior portion of cranial cavity
 appear within hours of head injury
 chronic subdural hematomas – slow bleeding over extended period (weeks to months)
• common in elderly and in people who abuse alcohol

91
Q

Cranial Nerves

A

• 12 pairs of cranial nerves on ventrolateral surface of brain (Fig 16.22)
• may be: sensory, special sensory, somatic motor, and/or parasympathetic motor, or mixed (sensory and motor) in function (Table 16.12)
o sensory = special senses (vision, smell, hearing, taste, equilibrium) and general senses (touch, proprioception, temperature, pain, pressure)
o somatic motor = control of skeletal muscles
o parasympathetic = regulation of glands and cardiac and smooth muscles

92
Q

cranial nerves are indicated by

A

• indicated by Roman numerals from anterior (rostral) to posterior (caudal)

93
Q

• Olfactory nerve (I) (

A

special sensory for smell – from olfactory epithelium through cribriform plate of ethmoid bone to olfactory bulbs and olfactory tracts
o only cranial nerve directly attached to cerebrum

94
Q

remaining cranial nerve originate or terminate where ?

A

• remaining cranial nerves originate or terminate within nuclei of diencephalon or brain stem

95
Q

• Optic nerve (II)

A

special sensory for vision - attaches directly to diencephalon
o passes through optic canal of sphenoid bone
o optic chiasm – medial (nasal) fibers from each optic nerve cross over to opposite side
o optic tracts = medial (nasal) fibers from contralateral side and lateral (temporal) fibers from ipsilateral side
o lateral geniculate of thalamus – then optic radiations to occipital cortex
• cranial nerves III-X, and XII – connect to brainstem
o N III, N IV, ophthalmic branch of N V, and N VI pass through superior orbital fissure of sphenoid (Fig 16.26)

96
Q

• Oculomotor nerve (III) (Fig 16.25)

A

somatic motor and parasympathetic
o supplies 4 of the muscles that move the eye: superior, inferior, and medial rectus muscles and inferior oblique muscles
o levator palpebrae superioris – raises upper eyelid
o smooth muscle that regulates the size of the pupil and shape of the lens of the eye

97
Q

• Trochlear nerve (IV)

A

somatic motor – controls movement of superior oblique muscle only

98
Q

• Trigeminal nerve (V)

A

mixed nerve - sensory and somatic motor
o only cranial nerve involved in sensory cutaneous innervation of head
 three sensory divisions: ophthalmic, maxillary, and mandibular

99
Q

• ophthalmic branch

A

= sensory – innervates orbital structures, the nasal cavity and sinuses and the skin of the forehead, eyebrows, eyelids and nose

100
Q

• maxillary branch

A

= sensory - passes through foramen rotundum of sphenoid bone

o sensory innervation of maxillary teeth, palate and gingiva, and skin of lower eyelid, upper lip, cheek and nose

101
Q

• mandibular branch

A

motor and sensory - passes through foramen ovale of sphenoid bone
o sensory innervation of mandibular teeth, tongue and gingiva

102
Q

 sensory innervation of blood vessels

A

responsible for pain of headache

103
Q

o motor to muscles of mastication

A

one middle ear muscle, one palatine muscle and two throat muscles
o proprioceptive information from same muscles plus temporomandibular joint, tongue, cheek
 damage may impede chewing

104
Q

o tic douloureux (trigeminal neuralgia)

A

sudden onset severe pain on one side face triggered by contact with lip, tongue or gums
 adults over 40 – cause unknown
 temporarily controlled by drug therapy but surgical therapy (rhizotomy) but cutting or cauterizing (burning) sensory nerve trunks carrying pain sensations

105
Q

• Abducens nerve (VI)

A

somatic motor – only to lateral rectus muscle of eye

106
Q

• Facial nerve (VII)

A

mixed nerve - somatic motor, sensory, parasympathetic
o passes through internal acoustic meatus of temporal bone
o somatic motor control all muscles of facial expression, small muscle in middle ear, and two hyoid muscles
o sensory for taste – anterior 2/3 of tongue
o parasympathetic: lacrimal glands, submandibular and sublingual salivary glands
o Bell’s Palsy = viral infection resulting in inflammation of facial nerve resulting in paralysis of facial muscles on affected side and loss of taste sensation (Clinical case, p.281)
 condition usually painless and resolves after few weeks or months
• recovery can be accelerated by corticosteroids and antiviral drugs

107
Q

• medulla oblongata

A

contains sensory and motor nuclei for N VIII (vestibular nerve), N IX, N X, N XI, N Xll
nerves IX, X, and XI - pass through jugular foramen (between occipital and temporal bones)

108
Q

• Vestibulocochlear Nerve (VIII)

A

= special sensory for hearing, balance and equilibrium
o passes through internal acoustic meatus of temporal bone
o vestibular nerve – receptors in vestibule and semicircular canals – involved in balance and equilibrium
o cochlear nerve – receptors in cochlea – involved in hearing

109
Q

• Glossopharyngeal Nerve (IX)

A

mixed nerve - somatic motor, sensory, parasympathetic
o somatic motor: one muscle of pharynx – involved in swallowing
o parasympathetic: parotid salivary glands
o sensory for: taste – posterior 1/3 of tongue, tactile sensation from posterior tongue, middle ear and pharynx, carotid arteries (blood pressure, carbon dioxide, oxygen and pH levels of blood)

110
Q

• Vagus nerve (X)

A

mixed nerve - somatic motor, sensory, parasympathetic
o branches radiate extensively
o somatic motor: muscles of soft palate, pharynx, and larynx
 damage to laryngeal branch can interfere with normal speech
o sensory: taste at root of tongue, inferior pharynx and larynx, aortic arch (blood pressure, carbon dioxide, oxygen and pH levels of blood), thoracic and abdominal organs
o parasympathetic* = main output for regulating viscera - smooth muscle function of thoracic (lungs) and abdominal organs (digestive organs and kidneys), and cardiac muscle

111
Q

• Accessory nerve (XI)

A

somatic motor - cranial root (connects to vagus) and spinal roots
o sternocleidomastoid and trapezius muscles

112
Q

• Hypoglossal nerve (XII)

A

somatic motor
o passes through hypoglossal canal of occipital bone
o supplies intrinsic muscles of tongue, thyrohyoid and geniohyoid muscles

113
Q

• cranial reflexes

A

arcs involving sensory and motor fibers of cranial nerves (Table 16.13)
o clinically important – means of assessing cranial nerve, specific nuclei and tracts in the brain

Anatomy 101 (14 decks)

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