chapters 7 8 single

8/14/2019 Chapters 7 8 Single

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Pons: Ventral Surface

Pontine protuberance Pontine sulcus

Cranial nerves Abducens Facial Vesitbulochoclear Trigeminal

Oculomotor Trochlear

Cerebral peduncle

foot of the cortex[cerebrum]


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Pons: 2 Divisions

Basis PontisPontine nuclei

Corticospinal tract

Corticobulbar tract

Cortcopontocerebellar

tract Rapid correction of

movements


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Pons: 2 Divisions Tegmentum

Reticular formation Specific sensory lemniscal

system Medial lemniscus

Trigeminal Spinothalamic

Central tegmental tract Basal ganglia -> midbrain ->

inferior olive

Locus ceruleus Involved in Parkinsons,

Alzheimers, Downs syndrome Output to:

Cortex, cerebellum,hippocampus, hypothalamus,and spinal cord


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Vestibulocochlear Nerve: CochlearDivision

Organ of CortiAuditory organ

Dorsal cochlear

nucleusHigh-frequency

sound

Ventral cochlearnucleus

Low-frequencysound


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Dorsal acoustic stria Ventral acoustic

stria

Aka trapezoid body

Intermediate

acoustic stria


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Lateral lemniscus Inferior colliculus

Medial geniculatenucleus

Thalamus

Auditory cortex

Heschels gyrus

Temporal lobe


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Olivocochlear bundle Origin: periolivary area

Destination: Organ of Corti

Feedback to hair cells

Possible functions

Protective against loud sound

Frequency selectivitySelective auditory attention

Example: speech in noisybackground


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Vestibulocochlear Nerve: vestibularDivision

Semicircular canals Angular acceleration

Utricle/Saccule

Linear accelerationGravity

Scarpas ganglion

Location of cell bodies Vestibular nerve

Vestibular nuclei

Cerebellum


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Input to Vestibular Nuclei

Vestibular nerve Spinal cord

Cerebellum Vestibular cortex


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Output of the Vestibular Nuclei

Spinal cordLateral vestibulospinal tract

Facilitate flexor motor neurons

Medial vestibulospinal tract

Facilitate extensor motorneurons

Dorsal motor nucleus of thevagus

Motion sickness

Nausea, sweating, vomiting


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Output of the Vestibular Nuclei Cerebellum

Via juxtarestiform body Primary vestibular cortexVia thalamus

Nuclei of extraocularmuscles

Medial longitudinal fasciculusProject on nuclei of

Oculmotor

Trochlear

Abducens


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Conjugate Eye Movements

yoked together Nystagmus

Involuntary rhythmic oscillations of the eyes

2 pathways

Medial longitudinal fasciculus

Reticular formation


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Medial Longitudinal FasciculusSyndrome

Paralysis ofadduction ipsilateralto MLF lesion

Nystagmus of theother eye


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Facial Nerve (VII)

SensoryEar

Spinal trigeminal

nucleus

Anterior 2/3 tongue

Nucleus solitarius


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Facial Nerve (VII)

MotorFace

Facial motor nucleus

Salivary glands

Submandibular

Sublingual

Lacrimal

Origin

Superior salivatorynucleus


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Central Facial Paresis

Bilateral innervation toupper facial muscles

Contralateral to lowerfacial muscles

Damage to one

hemisphere thereforeaffects lower facial

musclescontralaterally, only.


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Facial Nerve Lesions

Bells PalsyFacial nerve paralysis

Proximal to ganglion

Eyes can still tear up

Distal to ganglion

Motor fibers

Facial muscle paralysis

only


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Abducens (VI)

MotorLateral rectus

muscle

Modulated by

Corticospinal tract

Reticular nucleusVestibular nuclei


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Lesions of Abducens

Paralysis ofipsilateral lateralrectus muscle (B)

Diplopia (A)

double vision

When attempting togaze towardslesioned side


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Lateral Gaze Paralysis

Abducens nucleussends output tocontralateral

oculomotor nucleusMedial rectus

muscle of the othereye


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Trigeminal Nerve (V)

SensoryHead/Neck

Proprioception

Pain/temperature/touch

Semilunar ganglion

MotorMastication


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Pons: Clinical Correlates


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Caudal Basal Pontine Syndrome

Millard-GublerSyndrome

Lesion of abducens

Lesion of facial

Lesion of

corticospinal tract


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Tegmental Pontine Syndrome

Abducens Facial

Medial lemniscus


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One-and-a-half Syndrome

AbducensOne

Medial longitudinalfasciculus

Half

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