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Clarifications from last lecture

ParasympatheticRest and digest

Sympathetic

Fight or flight

Steven Hawking does have ALS.

Hes had it most of his adult life.

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Medulla Ventral Surface

Cranial Nerves (9-12)Glossopharyngeal (IX)

Vagus (X)

Accessory (XI)

Hypoglossal (XII)

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Medulla - Dorsal Surface

Posteromedian sulcus Posterolateral sulcus

ClavaGracile tract protuberance

Cuneate tubercle

Cuneate tract protuberance

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Fourth Ventricle

Contains CSF Choroid Plexus

Makes CSF

Space between

Medulla/Pons and

Cerebellum/medullaryvelums

Velum veil Thin membrane

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Internal Structure

3 levelsMotor (pyramidal) decussation

Sensory (lemniscal) decussation

Inferior olive

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Motor Decussation Level

Pyramidal decussation Corticospinal

Lower extremities

Lateral

Decussate last

Upper extremities

Medial

Decussate first

Corticobulbar

Cortex to cranial nerve

nuclei

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Pyramidal Decussation

Bilateral upperextremity paralysis

Rostral lesion

Hemiplegia cruciata

crossed

Opposite arm/leg

Caudal lesion

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Motor Decussation Level

Dorsal column nuclei Cuneate

C1 to T7

Gracile Below T7

Spinal trigeminal nucleus

Trigeminal nerve Pain, temperature, light

touch

Ipsilateral face

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Sensory Decussation Level Medial lemniscus

DC-ML Kinesthesia Discriminative touch Contralateral

Accessory cuneatenucleus Not part of DC-ML

Spinocerebellar system Fibers from above C8 Projects to cerebellum

Hypertension activates Bradycardyia Hypotension

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Inferior Olive Level

Inferior olivarynuclear complex

Principal olive

Dorsal accessoryolive

Medial accessoryolive

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Inferior Olive Level

Restiform body Inferior cerebellar

peduncle

Foot 2 other cerebellar

pedunclesMiddle

Pons

Superior Midbrain

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Medulla: Cranial Nerve Nuclei

Cranial Nerves 8-12Vestibulochoclear (VIII)

Glossopharyngeal (IX)

Vagus (X)

Accessory (XI)

Hypoglossal (XII)

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Hypoglossal (XII)

Hypoglossalnucleus

Motor

Tongue

Nerve

Travels betweenolive and pyramid

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Hypoglossal Lesions (andSurrounding Structures)

Nerve Nerve and medial

lemniscus (DC-ML)

Nerve and pyramid

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Accessory Nerve: Roots

SpinalSpinal cord

Ventral horn C1-C6

Nucleus ambiguus

Cranial

Medulla

Accessory nucleus

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Accessory Nerve: Output Larynx

Recurrent laryngealnerve

Galen and the silent pig

Some neck muscles

Lesions

Winged scapula

Sagging shoulder

Weak turning head toopposite side

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Vagus Nerve

Dorsalmotornucleus

Vestibularinput

Motion

sickness Nausea,

vomiting,

heart rate

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Glossopharyngeal Nerve Motor

Nucleus ambiguus Pharynx

Swallowing

Speech

Inferior salivatorynucleus Dry mouth

Fear/anxiety

Salivation Food odor

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Glossopharyngeal Nerve Sensory

Posterior 1/3 oftongue

Carotid sinus nerve Chemoreceptor/bar

oreptor

Increase pressureactivates it

It causes vagus

nerve to slow heartrate

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Nucleus Solitarius

2 zonesTaste

Facial nerve

Anterior 2/3 of tongue

Glossopharyngeal nerve

Posterior 1/3 of tongue

Vagus nerve Epiglotts

Output to posterior thalamus

Then primary gustatory cortex

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Nucleus Solitarius

2 zonesCardio-respiratory (also

visceral)

Input Glosspharyngeal

Vagus

Output Nucleus ambiguus

Dorsal motor nucleus of Vagus

Medullary reticular formation

Parabrachial pontine nucleus Visceral to amygdala &

hypothalamus

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Medulla and Respiratory Function

Nucleus solitarius

Inspiration

Nucleus ambigguus

Inspiration Expiration

Sleep apnea

Stop breathing when sleeping

Lesions of nucleus ambiguus & reticular formation

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Sneezing

Nasal mucosa

Trigeminal nerve

Sneezing center

Medulla 2 phases

Nasal nasal secretion

Respiratory muscular output

Close eyes, deep breath, close pharynx, forceful expiration,explosive air release through mouth and nose

You cant sneeze with your eyes open

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Vomiting Instinctive defensive reaction

Triggers Motion

Adverse drug reactions

Trauma Toxin ingestion

Chemoreceptor trigger zone in floor of fourth ventricle[devoid of blood-brain barrier]

Taste receptors

Vestibular

Autonomic input from intestines

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Medulla: Clinical Correlates

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Medial Medullary Syndrome

Occlusion of anteriorspinal artery orvertebral artery

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Lateral Medullary Syndrome Occlusion of

vertebral artery orposterior inferior

cerebellar artery Horners

Miosis small pupil

Droopy eyelid ptosis

Lack of facial sweat -anhidrosis

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Lateral Medullary Syndrome:

Sensory Patterns

#1 26%

#2 24%

#3 18%

#4 20%

#5 8%

#6 4%