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Clinical Neuroanatomy
Exam III
206
Anatomy
Undergraduate 4
10/25/2011

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Cards

Term
What three things make up the brainstem?
Definition
        1. Medulla Oblongata
        2. Pons
        3. Midbrain
Term
What are the three functions of the brainstem?
Definition
  1. Serves as a conduit for the ascending and descending tracts between the spingal cord and the brain.
  2. Contains important reflex centers, controlling the respiratory and the cardiovascular systems.
  3. It contains nuclei of CNIII-CNXII
Term
Where does the decussation (crossing) of pyramids take place?
Definition
central canal at the inferior half of the medulla
Term
What is the decussation of pyramids?
Definition
Where 2/3 of the corticospinal fivers cross over and continue down the spinal cord as the Lateral Corticospinal Tract
Term
Where do the Fasciculus gracilis and the Fasciculus cuneatus terminate?
Definition
In nuclesu gracilis and cuneatus
Term
What does the nucleus of the spinal tract of the trigeminal nerve correspond to?
Definition

the substantia gelatinosa

 

they become continuous

Term
Where does the decussation (crossing) of Lemnisci take place?
Definition
in the central canal at the inferior half of the medulla, above the pyramidal decussation
Term
What is the decussation of the lemnisci?
Definition
where fibers of the neurons originating in the nucleus gracilis and cuneatus cross to the opposite side anterior to the central grey matter and continue upwards as the medial lemniscus
Term
What is the spinal lemniscus?
Definition

consists of the lateral and anterior spinothalamic tracts and the spinotectal tract, which lie lateral to the decussation of the lemnisci

 

they convey sensory information to the thalamus

 

**Accessory nucleus (CN XI) and Hypoglossal nucleus (CN XII) are found here**

Term
Where is the level of the olives?
Definition
the inferior part of the 4th ventricle
Term
What is the olivary nuclear complex involved with?
Definition

voluntary muscle movements

 

it receives afferents from the spinal cord, cerebellum and cerebral cortex

 

it sends fibers to the cerebellum

Term
What is found at the level of the olives?
Definition
  • olivary nuclear complex
  • vestibular nuclear complex
  • anterior post-cochlear nuclei
  • nucleus ambiguus

 

 

Term
where is the central grey matter found?
Definition
beneath the floor of the 4th ventricle
Term

What is found in the floor of the 4th ventricle?

(Medial to Lateral)

Definition
  1. Hypoglossal nucleus
  2. Dorsal nucleus of vagus nerve (CNX)
  3. Nucleus of tractus solitarius
  4. Medial and inferior vestibular nuclei
Term
Where is the medial longitudinal fasciculus?
Definition
each side of the midline, anterior to the hypoglossal nucleus
Term
What is the medial longitudinal fasciculus?
Definition

consists of ascending and descending tracts

 

connects the nuclei innervating the muscles of the eye and the vestibular nerve

 

coordinates eye movement

 

mediates nystagmus and lateral conjugate gaze

Term
what is the reticular formation?
Definition

consists of a deeply placed continuous network of nerve cells and fivers that extends from the spinal cord, through the medulla, the pons, midbrain, sub-thalamus, thalamus, and hypothalamus.

 

it influences skeletal muscle activity, somatic and visceral sensations, the autonomic and endocrine systems and the level of consciousness.

Term
What is the Arnold-Chiary Phenomenon?
Definition

Herniation of the tonsils of the cerebellum and the medulla through the foramen magnum.

 

Results in the blockage of the CSF passage at the roof of the 4th ventrical, causing internal (obstructive) Hydrocephalus which affects 1/1000 births.

 

Affected children may have: dysphonia, laryngeal stridor and respiratory arrest due to the involvement of CNX.

Term
What is the Lateral Medullary Syndrome of Wallenberg?
Definition

The lateral part of the medulla is supplied by the posterior inferior cerebellar artery, a branch of the vertebral artery. Thrombosis of either of these arteries causes:

  • Dysarthria and dysphagia (ipsilateral pharyngeal and palatal muscle paralysis due to being innervated by the nucleus of ambiguus, CNX and CNXI)
  • Analgesia and thermoanesthesia on the ipsilateral side of the face (damage to CNV).
  • Vertigo, nausea, vomiting and nystagmus (damage to the vestibular nuclei, CN VIII)
  • Horner's syndrome (damage to the ipsilateral descending sympathetic fibers)
  • Gait and limb ataxias due to damage to the cerebellum and inferior cerebellar peduncle.
  • Contralateral loss of sensation of pain and temperature (damage to spinothalamic tract)
Term
What is Medial Medullary Syndrome?
Definition

The medial side of the medulla is supplied by the vertebral artery and its thrombosis leads to:

  • Damage to pyramidal tract (contralateral hemiparesis)
  • Damage to the medial Lemniscus (impaired contralateral sensation of position and movement and 2 point discrimination)
  • Damage to the hypoglossal nerve (ipsilateral paralysis of the tongue muscles)
Term
Where is the pons located?
Definition

Between the medulla oblongata (below) and the midbrain (above).

 

Anterior to the cerebellum and is connected to the cerebellum by the Middle Cerebellar Peduncle.

Term
On the anterior side of the pons, there is the basilar groove. What emerges from either side of this groove?
Definition
The motor and sensory roots of the Trigeminal nerve (CNV)
Term
What three nerves emerge from the groove between the pons and the medulla?
Definition
  1. Abducent (CNVI)
  2. Facial (CNVII)
  3. Vestibulocochlear (CNVIII)
Term
The posterior surface of the pons is hidden by the cerebellum and helps to form the upper part of what ventricle?
Definition
4th ventricle
Term
What is the reason for the bluish-grey color of the upper part of the sulcus limitans in the pons?
Definition

Called Substantia Ferruginea

 

Due to a group of cells deep in there

Term
The posterier surface of the pons has what 6 structures?
Definition
  1. Superior cerebellar peduncle
  2. Median Sulcus
  3. Medial Eminence
  4. Sulcus Limitans
  5. Area vestibuli
  6. Facial colliculus
Term
What produces the facial colliculus of the posterior pons?
Definition
CNVII winding around the nucleus of CNVI
Term

What are the two parts of the internal pons?

 

What causes the segmentation?

Definition
  1. Posterior Part - Tegmentum
  2. Anterior Part - Basal Part

Transversely running fibers called the Trapezoid body cause the segmentation.

Term
What two levels can the pons be studied at?
Definition
  1. transverse section through its caudal part passing through the facial colliculus
  2. transverse section through its cranial part, the trigeminal nucleus
Term
What 4 things are found in the pons and what are their functions?
Definition
  1. Nuclei of CNVII (vestibular nuclei) - regulates postural mechanisms and vestibulo-ocular reflexes
  2. Motor nucleus of CNVII (facial nerve) - innervates all facial expression muscles
  3. Nucleus of CNVI (motor to the lateral rectus muscle of the eye) - involved in lateral gaze
  4. Motor nucleus of CNV (trigeminal nerve) - innervates the muscles of mastication
Term
Which 6 nuclei are found at the level of the facial colliculus?
Definition
  1. facial nucleus
  2. abducent nucleus
  3. medial vestibular nucleus
  4. spinal nucleus of CNV
  5. pontine nuclei
  6. trapezoid nuclei
Term
What 3 motor and 2 sensory tracts are found at the level of the facial colliculus?
Definition

Motor

1. Corticospinal and corticonuclear tracts

2. Transverse pontine fibers

3. Medial longitudinal fasciculus

 

Sensory

1. Spinal tract of CNV

2. lateral, spinal, and medial Lemnisci

Term
What 4 nuclei are found at the level of the trigeminal nuclei?
Definition
  1. Main sensory nucleus of CNV
  2. Main motor nucleus of CNV
  3. Pontine nuclei
  4. Trapezoid nuclei
Term
Which 3 motor and 1 sensory tracts are found at the level of the trigeminal nuclei?
Definition

Motor

1. Corticospinal and corticonuclear tracts

2. Transverse pontine fibers

3. medial longitudinal fasciculus

 

Sensory - Lateral, spinal, and medial lemnisci

Term
What are the 7 main symptoms seen when there are tumors in the pons?
Definition
  1. ipsilateral facial muscle weakness (CNVII)
  2. lateral rectus muscle weakness (nucleus of CNVI)
  3. jaw muscle weakness (CNV)
  4. weak hearing (cochlear nuclei) and Nystagmus (vestibular nuclei)
  5. Contralateral hemiparesis or quadriparesis (corticospinal fibers)
  6. Conjugate eye movement impairment (medial longitudinal fasciculus that connects nuclei of CNII, CNIV and CNVI)
  7. no touch sensation in face and contralateral loss of touch in limbs and trunk (medial and spinal leminisci)
Term
What happens when there is a unilateral pontine hemorrhage? (3 issues)
Definition
  1. ipsilateral facial paralysis
  2. contralateral paralysis of the limbs
  3. paralysis of conjugate eye movement (CNVI and MLF)
Term
What does the midbrain connect?
Definition
the pons and cerebellum to the forebrain
Term
What are the 4 colliculi on the posterior surface of the midbrain collectively referred to as?
Definition
corpora quadrigemina
Term
in the midbrain, what are the 2 superior colliculi involved in?
Definition
visual reflexes
Term
in the midbrain, what are the 2 inferior colliculi involved in?
Definition
hearing
Term
what nerve is found in the midbrain at the level of the inferior colliculus?
Definition
Trochlear Nerve (CNIV)
Term
what nerve is found in the midbrain at the level of the superior colliculus?
Definition
Oculomotor Nerve (CNIII)
Term
what is found on the anterior side of the midbrain?
Definition
the interpeduncular fossa
Term
in the midbrain, what connects the superior and inferior colliculus to the lateral and medial geniculate bodies (respectively)?
Definition
superior brachium and inferior brachium
Term
What are the 3 things to be found within the midbrain? (internal structure)
Definition
  1. cerebral peduncle (composed of crus cerebri)
  2. tegmentum
  3. substantia nigra (between the cerebral peduncle and the tegmentum)
Term
What channel cuts through the midbrain?
Definition
Cerebral aqueduct of Sylvius
Term
What three tracts are found in the crus cerebri?
Definition
  1. coricospinal
  2. coricobulbar
  3. corticopontine
Term
where in the midbrain is the tectum?
Definition
posterior to the cerebral aqueduct of sylvius
Term
What are the four swellings of the tectum?
Definition
2 superior and 2 inferior colliculi
Term
what surrounds the cerebral aqueduct of sylvius in the midbrain?
Definition
central gray matter
Term
what 6 things are found at the level of the inferior colliculus of the midbrain?
Definition
  1. inferior colliculus
  2. cerebral aqueduct of sylvius
  3. trochlear nucleus
  4. periaqueductal gray matter
  5. substantia nigra
  6. MLF, medial leminiscus, spinal leminiscus
Term
What does the nucleus of the inferior colliculus of the midbrain receive?
Definition

binaural auditory inputs through the lateral leminiscus

 

it projects the medial geniculate body via the brachium of the inferior colliculus

Term
what does the cerebral aqueduct of sylvius do?
Definition

connects the 3rd and 4th ventricles

 

**blockage causes hydrocephalus**

Term
what does the trochlear nucleus at the level of the inferior colliculus of the midbrain do?
Definition
encircles the periaqueductal gray matter and leaves the midbrain dorsally to innervate the superior oblique muscle of the eye
Term
what 4 things are found in the periaqueductal gray matter?
Definition
  1. locus ceruleus
  2. mesencephalic nucleus and tract
  3. dorsal tegmental nucleus (endogenius pain control)
  4. dorsal nucleus of raphe (5ht neurons)
Term
what is substantia nigra composed of?
Definition

pars compacta (dorsal)

pars reticulata (ventral)

 

receives GABAergic fibers from stratum

 

projects dopaminergic fivers to striatum

Term
What is Meniere's Disease?
Definition
loss of balance and ringing in the ear, caused by edema of the labyrinth or inflammation of the vestibular nerve
Term
what's important about the superior colliculus?
Definition

receives visual input form the retina, area 8 and area 19

 

receives auditory input to mediate audiovisual reflexes

 

involved in detection of movement in the visual field (searching, tracking, visual orientation)

Term
what is the brachium of the superior colliculus involved in?
Definition
optic and puillary reflexes
Term
what is the Edinger-Westphal nucleus?
Definition

parasympathetic fibers to constrictor pupil and cilliary muscles

 

involved in pupillary light reflex and accomodation

Term
what does the red nucleus do?
Definition
has facilitatory influence on the flexor muscles
Term
What 6 things are found at the level of the superior colliculus in the midbrain?
Definition
  1. superior colliculus
  2. brachium of superior colliculus
  3. cerebral aqueduct of sylvius and PAG
  4. Edinger-Westphal Nucleus
  5. Red Nucleus
  6. MLF, ML, SPL, Substantia Nigra
Term
which 4 nuclei are found at the level of the inferior colliculi of the midbrain?
Definition
  1. inferior colliculus
  2. substantia nigra
  3. trochlear nucleus
  4. mesencephalic nuclei of CNV
Term
which 4 motor and 2 sensory tracts are found at the level of the inferior colliculi in the midbrain?
Definition

Motor

1. Corticospinal and corticonuclear tracts

2. temporopontine

3. frontopontine

4. medial longitudinal fasciculus

 

Sensory

1. lateral, trigeminal, spinal, and medial leminisci

2. decussation of superior cerebellar peduncles

Term
which 6 nuclei are found at the level of the superior colliculi of the midbrain?
Definition
  1. superior colliculus
  2. substantia nigra
  3. oculomotor nucleus
  4. edinger-westphal nucleus
  5. red nucleus
  6. mesencephalic nucleus of CNV
Term
what are the 5 motor and 1 sensory tracts found at the superior colliculi level of the midbrain?
Definition

Motor

1. corticospinal and corticonuclear tracts

2. temporopontine

3. frontopontine

4. medial longitudinal fasciculus

5. decussation of rubrospinal tract

 

Sensory - trigeminal, spinal, and medial leminisci

Term
What is Weber's Syndrome?
Definition

Occlusion of a branchy of the posterior cerebral artery that supplies the midbrain: (HAS PARALYSIS)

  1. lesion to CNIII and crus cerebri - ipsilateral ophthalmoplegia
  2. contralateral paralysis of the lower part of the face, tongue, arm, and leg
  3. eyeball deviated laterally
  4. ptosis of the upper lid
  5. pupil is dilated and fixed to light and accommodation

 

Term
What is Benedikt's Syndrome?
Definition

Similar to Weber Syndrom, but necrosis is involves the medial leminiscus and the red nucleus (NO PARALYSIS)

  1. contralateral hemianesthesia
  2. contralateral involuntary movements of the limbs
Term
What are the three main lobes of the cerebellum?
Definition
  1. Anterior
  2. Middle
  3. Flocculonodular 
Term
What are the 3 main fissures of the cerebellum?
Definition
  1. Primary Fissure (between superior & middle lobes)
  2. Uvulonodular Fissure
  3. Horizontal Fissure 
Term
What is the constricted middle part of the cerebellum called?
Definition
Vermis
Term
In the cerebellum, the gray matter makes up what? And the white matter?
Definition

Gray matter - cerebellar cortex

white matter - central

Term
what are found in the interior of the cerebellum?
Definition
intercerebellar nuclei
Term
what is the cerebellar cortex folded into?
Definition

folia

 

each folium has a core of white matter covered superficially by grey matter

Term
What are the three layers of the cerebellar cortex? (start superficially)
Definition
  1. Molecular layer - external
  2. Purkinje Cell layer - middle
  3. Granular layer - internal 
Term

what kind of cells does the molecular layer of the cerebellar cortex contain?

 

Definition

stellate cells and the inner basket cells

 

found along the folia's long axis

Term
where are dendrites of purkinje cells located?
Definition
pass into molecular layer and branch enormously
Term
what covers the distal branches of the purkinje cell dendrites?
Definition
short, thick denderitic spines
Term
what do denderitic spines of purkinje cells synapse with?
Definition
synaptic contacts with parallel fibers of the granule cells
Term
where is the axon of the purkinje cell located?
Definition

passes through the tranular layer and enters the white matter where it acquires a myelin sheath

 

terminate in cerebellar nuclei

Term
what cells are found in the granular layer of the cerebellar cortex?
Definition
granular cells and golgi cells
Term
how many dendrites do granular cells have?
Definition

4-5

 

have synaptic contacts with the mossy fibers

Term
where is the axon of the granular cells found?
Definition
passes into the molecular layer and bifurcates at a T junction
Term
what does parallel fiber of granular cells make synapse with?
Definition
dendrite of purkinje cells
Term

where do golgi cells send their dendrites?

 

their axons?

Definition

dendrites to molecular layer

 

axons synapsw with dendrites of granular cells

Term
what are the three functional areas of the cerebellar cortex?
Definition
  1. cortex of vermis
  2. intermediate zones
  3. lateral zone
Term
what is the vermis of the cerebellar cortex involved in?
Definition
movements of the long axis of the body such as the neck, shoulder, thorax, abdomen, and the hips
Term

what are the intermediate zones of th cerbellar cortex responsible for?

 

Definition

control the muscles of the distal parts of the limbs expecially the hands and the feet

 

immediately lateral to the vermis

Term
what are the lateral zones of the cerebellar cortex involved in?
Definition
planning of sequential movements of the entire body and with the conscious assessment of movement errors
Term
what does the flocculonodular lobe of the cerebellum influence?
Definition

vestibulospinal and reticulospinal tracts

 

concerned with balance

Term
what does the intermediate zone of the cerebellum deal with?
Definition

influences the rubrospinal tract

 

concerned with posture and muscle tone

Term
what is the lateral zone of the cerebellum concerned with?
Definition

influences from cerebral cortex via the thalamus and the rubrospinal tract

 

concerned with muscle coordination

Term
what are the intracerebellar nuclei? (lateral to medial)
Definition
  1. dentate nucleus
  2. emboliform nucleus
  3. globose nucleus
  4. fastigial nucleus 
Term
what do intercerebellar nuclei contain?
Definition
large multipolar neurons whose axons form the cerebellar out flow in the superior and inferior cerebellar peduncles
Term
what does the dentate nucleus of the intracerebellum receive?
Definition
inputs from the lateral parts of the cerebellar hemispheres
Term
what do the globose and emboliform nuclei of the intracerebellum receive?
Definition
inputs from the intermediate part of the cerebellar hemisphere
Term
what does the fastigial nucleus of the intracerebellum receive?
Definition
inputs from vermis and flocculonodular lobe
Term
where do most outputs of the vermis and flocculonodular lobe of the cerebellum go?
Definition
vestibular nuclei
Term
what are the three groups of white matter fibers of the cerebellum?
Definition
  1. intrinsic fibers - don't leave cerebellum; connect different folia and vermis on same side; some connect 2 hemispheres
  2. afferent fibers - form greater part of white matter; proceed to cortex; lose myelin sheath and end as either climbing or mossy fibers. most pass through inferior and middle cerebellar peduncles
  3. efferent fibers - output of the cerebellum; axons of the neurons of the cerebellar nuclei upon which the axon of the purkinje cells synapse. most pass through superior and middle cerebellar peduncles.
Term
what are the two types of afferent fibers that enter the cerebellar cortex?
Definition
climbing fibers and mossy fibers
Term
what are climbing fibers?
Definition

terminal fibers of the olivocerebellar tracts

 

enter molecular layer of cortex and branch to make multiple synapses with only one purkinje cell

 

few side branches synapse with adjacent stellate and basket cells

Term
what are mossy fibers?
Definition

terminal fibers of all other cerebellar afferents

 

have multiple branches and exert more excitatory effect

 

single fiber can stimulate thousands of purkinje cells through granule cells

 

remaining cells in the cerebellar cortex, the golgi, basket and stelate cells limit the area excited by the purkinje cells by inhibiting these

Term
what are the three peduncles (bundles) in the cerebellum?
Definition
  1. inferior - arise form medulla
  2. middle - arise from pons
  3. superior - arise from lower midbrain 
Term
Where is the origin of the Corticopontocerebellar pathway?
Definition
Cerebral cortical neurons (frontal, parietal, temporal and occipital lobes)
Term
What is the corticopontocerebellar pathway and where does it pass through?
Definition
Cerebellar afferent fibers that pass through the internal capsule and gets control from the cerebral corex
Term
Where does the corticopontocerebellar pathway terminate?
Definition

pontine nuclei in the brainstem

 

produce the transverse fibers of the pons, and cross the midline to the opposite side to reach the cerebellar hemisphere

Term
What is the cerebro-olivocerebellar pathway and where does it pass through?
Definition
cerebellar afferent fibers that pass through the internal capsule and gets control from cerebral cortex
Term

where does the Cerebro-olivocerebellar pathway originate?

 

terminate?

Definition

originates in the cerebral cortical neurons

 

terminates at the bilateral olivary nuclei

 

fibers from the inferior olivary nuclei cross the midline to the opposite side cerebellar hemisphere and terminate as climbing fibers

Term
What is the cerebro-reticulocerebellar pathway and where does it pass through?
Definition

cerebellar afferent fibers that pass through the internal capsule and function in the control of voluntary movements.

 

cerebral cortex informs the cerebellum about initiation of th emovement, so that it can be monitored by the cerebellum

Term

where does the cerebro-reticulocerebellar pathway originate?

 

terminate?

Definition

originates at the cerebral cortical neurons

 

terminates at boths sides of the reticular formation

 

the reticulocerebellar fibers enter the cerebellar hemisphere on of the side

Term
what are the origin and termination of the vestibulocerebellar tract?
Definition

originate in the innter ear (utricle, saccule, and semicircular canals)

 

terminate as mossy fibers to the cerebellum

Term
what is the function of the vestibulocerebellar tract?
Definition
controlling the position and movement of the head
Term

what do the anterior and posterior spinocerebellar tracts convey information about?

 

how do they terminate?

Definition

muscle and joints

 

end as mossy fibers

Term

Pontocerebellar Fibers

 

Origin?

 

Cells?

 

Cerebellar Peduncle?

Definition

Origin - Cortex

 

Cells - Pontine Nuclei

 

Middle Cerebellar Peduncle

Term

Dorsal Spinocerebellar Tract (a Spinocerebellar Pathway)

 

Origin?

 

Cells?

 

Cerebellar Peduncle?

Definition

Origin - Leg Proprioceptors

 

Cells - Nucleus dorsalis of Clark

 

Inferior Cerebellar Peduncle

Term

Cuneocerebellar Tract (a Spinocerebellar Pathway)

 

Origin?

 

Cells?

 

Cerebellar Peduncle?

Definition

Origin - Arm Proprioceptors

 

Cells - External Cuneate Nucleus

 

Inferior Cerebellar Peduncle

Term

Ventral Spinocerebellar Tract (a Spinocerebellar Pathway)

 

Origin?

 

Cells?

 

Cerebellar Peduncle?

Definition

Origin - Leg Interneurons

 

Cells - Spinal Cord Neurons

 

Superior Cerebellar Peduncle

Term

Rostral Spinocerebellar Tract (a Spinocerebellar Pathway)

 

Origin?

 

Cells?

 

Cerebellar Peduncle?

Definition

Origin - Arm Interneurons

 

Cells - Spinal Cord Neurons

 

Superior & Inferior Cerebellar Peduncles

Term

Climbing Fibers

 

Origin?

 

Cells?

 

Cerebellar Peduncle?

Definition

Origin - Red Nucleus, Cortex, Brainstem, Spinal cord

 

Cells - Inferior Olivary Nucleus

 

Inferior Cerebellar Peduncle

 

Term

Vestibular Inputs

 

Origin?

 

Cells?

 

Cerebellar Peduncle?

Definition

Origin - Vestibular System

 

Cells - Vestibular Ganglia & Vestibular Nuclei

 

Juxtarestiform Body

Term

The major input source of the cerebellum is the _______1______ systems that originate in the __2__ cortex, primary ___3___ cortex, and __4___ cortex and relay through the ___5___ nuclei.

_______6_______ fibers then decussate and enter the cerebellum via the __7___ cerebellar peduncle.

Definition
  1. Corticopontine
  2. Motor
  3. Sensory
  4. Visual
  5. Pontine
  6. Pontocerebellar
  7. Middle 
Term
What are the two types of fibers found in cerebellar inputs?
Definition
climbing and mossy fibers
Term

What is the Globose-Emboliform-Rubral Pathway?

 

What's its origin?

 

Where does it terminate?

Definition

Cerebeller Efferent Fibers that control ipsilateral motor activity

 

Originate - Clobose and Emboliform NN in Cerebellum

 

Terminate - contralateral red nucleus, then via rubrospinal tract to ipsilateral LMN.

Term

What is the Dento-Thalamic Pathway?

 

Where does it originate?

 

Where does it terminate?

Definition

Cerebellar Efferent Fibers that control ipsilateral motor activity

 

Originate - Dentate Nucleus (cerebellum)

 

Terminate - contralateral thalamic nuclei, then to contralateral cerebral cortex

Term

What is the Fastigial Vestibular Pathway?

 

Where does it originate?

 

Where does it terminate?

Definition

Cerebellar Efferent Fibers that control ipsilateral extensor tone

 

Originate - Fastigial Nucleus (Cerebellum)

 

Terminate - Vestibular nuclei, then via vestibulospinal tract to ipsilateral LMN.

Term

What is the Fastigial Reticular Pathway?

 

Where does it originate?

 

Where does it terminate?

Definition

Cerebellar Efferent Fibers that control ipsilateral muscle tone

 

Originate - Fastigial Nucleus (Cerebellum)

 

Terminate - reticular formation, then via reticulospinal tract to ipsilateral LMN.

Term

Lateral Hemispheres

 

Deep Nuclei?

 

Cerebellar Peduncle?

 

Output target?

Definition

Deep Nuclei - Dentate Nucleus

 

Superior Cerebellar Peduncle

 

Output Target - Ventrolateral Nucleus of Thalamus (VL), Parvocellular Red Nucleus

Term

Intermediate Hemispheres

 

Deep Nuclei?

 

Cerebellar Peduncle?

 

Main Target?

Definition

Deep Nuclei - Interposed Nuclei

 

Superior Cerebellar Peduncle

 

Main Target - Ventrolateral Nucleus of the Thalamus (VL) and Magnocellular Red Nucleus

Term

Vermis

 

Deep Nuclei?

 

Cerebellar Peduncle?

 

Main Target?

Definition

Deep Nuclei - Fastigial Nuclei

 

Uncinate Fasciculus (travels with Superior Peduncle)

 

Main Target - Ventrolateral Nucleus of Thalamus and Tectum

Term

Inferior Vermis & Flocculonodular Lobe

 

Deep Nuclei?

 

Cerebellar Peduncle?

 

Main Target?

Definition

Deep Nuclei - Vestibular Nuclei & Fastigial Nuclei

 

Juxtarestiform body (travels with inferior cerebellar peduncle)

 

Main target - medial longitudinal fasiculus (eye movement pathways)

Term
What is an acute cerebellar lesion?
Definition
produce sudden, severe signs and symptoms, but there is considerable recovery perhaps due to compensation of loss of cerebellar function by other areas of the CNS
Term
What are chronic lesions of the cerebellum?
Definition

produce much less severe symptoms and signs than acute lesions do.

 

IE - slowly growing tumor

Term
What is hypotonia as a result of a cerebellar lesion?
Definition

the muscles lose resilience to palpation. Shaking the limb produces excessive movemtns of the terminal joints

(loss of cerebellar influence on the simple stretch reflex)

Term
What are postural changes and alterations of gait as a result of a cerebellar lesion?
Definition
head is often rotated and the shoulder is lower on the affected side. Legs are stiff to compensate for loss of tone. Lurching on the affected side occurs.
Term
What is ataxia as a result of a cerebellar lesion?
Definition

Disturbances of voluntary movement

 

the muscles contract irregularly and weakly

 

Decomposition of movement - muscles fail to work harmoniously

 

Can't touch index finger to nose

Term
What is an Intension Tremor as a result of a cerebellar lesion?
Definition
during fine movements, such as button clothes, writing, and shaving, shaking occurs
Term
What is Dysdiachokinesia as a result of a cerebellar lesion?
Definition

inability to perform alternating movements regularly and rapidly.

 

Pronation/Supination of hand is slow, jerky and incomplete on the lesion side.

Term
What are the reflex disturbances as a result of a cerebellar lesion?
Definition

pendular knee jerk, tapping on the patellar tendon induces multiple flexion and extensions of the knee

(loss of influence of stretch reflex)

Term
How do cerebellar lesions disturb ocular movement?
Definition

Nystagmus

(pendular type or jerk nystagmus)

Term
What kind of speech issue can a cerebellar lesion cause?
Definition
Dysarthria, due to ataxia of the muscles of the larynx
Term
What are the differences in truncal and appendicular ataxias?
Definition

Truncal - lesion of vermis causes wide-based, unsteady, staggering gait. Patient will often fall toward the side of the lesion and in severe cases they cannot even sit up without assistance

 

Appendicular - lesion of intermediate and lateral regions which affects finger to nose test

Term
What are the 2 common causes of acute ataxia?
Definition
toxin ingestion and ischemic or hemorrhagic stroke
Term
What are the 4 common causes of chronic ataxia?
Definition

Brain metastases

alcoholism

multiple sclerosis

degenerative disorders of the cerebellum

Term
What is sensory ataxia?
Definition

Occurs when dorsal column - medial lemniscus pathway is damaged.

 

Impaired proprioception occurs.

 

Function improves with visual input and worsens with eyes closed or in the dark.

Term
What are the 3 main causes of chronic ataxia in children?
Definition

cerebellar astrocytoma

 

medulloblastoma

 

Friedreich's ataxia - idiopathic degeneration of dorsal columns and spinocerebellar tracts

Term
What are the 3 main arteries that supply the cerebellum?
Definition

posterior inferior cerebellar artery

 

anterior inferior cerebellar artery

 

superior cerebellar artery

Term
In which cerebellar arteries are infarcts more common?
Definition

PICA and SCA

 

Not AICA

Term
What are the main 7 symptoms of cerebellar infarcts?
Definition
  1. Vertigo
  2. Nausea
  3. Vomiting
  4. Horizontal Nystagmus
  5. Limb Ataxia
  6. Unsteady Gait
  7. Headache 
Term
What are the differences in lateral medullary infarcts and large cerebellar infarcts?
Definition

Lateral Medullary Infarcts - Medullary symptoms also accur including Horner's Syndrome

 

Large Cerebellar Infarcts - cause cerebellar swelling leading to block of 4th ventricle apertures and hydrocedphalus

 

**Swelling in the posterior foss is life-threatening due to potential for brainstem compression!**

Term
What is the largest part of the brain?
Definition
Cerebrum
Term
Where is the cerebrum located?
Definition
Situated in the anterior and middle cranial fossae
Term
What are the two regions of the cerebrum?
Definition

Central Core (Diencephalon)

Cerebral Hemispheres (Telencephalon)

Term
The Diencephalon consists of the 3rd ventricle. What are the 4 structures that form its boundaries?
Definition

Thalamus

Subthalamus

Epithalamus

Hypothalamus

Term
What 4 structures are included in the inferior surface of the diencephalon?
Definition

optic chiasm

optic tract

infundibulum with the tuber cinereum

mammillary bodies

Term
Describe the superior surface of the diencephalon.
Definition

It's concealed by the fornix (originating from the hyppocampus of the temporal lobe and arches posteriorly over the thalamus to join the mammillary body).

 

Superior wall of the diencephalon is formed by the roof of the 3rd ventricle.

Term

What is the lateral surface of the diencephalon bound by?

What does that consist of?

Definition

Bounded by the internal capsule of white matter

 

Consists of nerve fibers that connect the cerebral cortex with the brainstem and the spinal cord

Term
Describe the medial surface of the diencephalon.
Definition

Diencephalon is divided into two symmetrical halves by the 3rd ventricle, therefore its medial surface is also the lateral surface of the third ventricle.

 

The medial wall is formed by the thalamus (superior) and the hypothalamus (inferior)

 

Contains hypothalamic sulcus

Term
What is the thalamus?
Definition

Large, ovoid mass of gray matter that forms the major part of the diencephalin.

 

Important cell station that receives sensory tracts (NOT olfactory pathway) mainly from the contralateral side.

 

Information is integrated in thalamuse and relayed to the cerebral cortex and many other subcortical regions.

Term
How are lesions of the thalamus caused?
Definition

thrombosis

 

hemorrhage of a supplying artery

Term
What does a lesion of the thalamus cause?
Definition
contralateral impairment of all sensation such as touch, tactile localization and discrimination, and loss of appreciation of joint movements
Term
Where is the subthalamus found?
Definition

Lies inferior ot the thalamus

 

Between the thalamus and the tegmentum of the midbrain

Term
What cells and tracts are found in the subthalamus?
Definition

crainial ends of the red nucleus and the substantia nigra

 

parts of the medial, spinal, and trigeminal leminisci

Term
Describe the sunthalamic nucleus.
Definition

similar to a binconvex lens in shape

 

involved in the control of muscle activity through its connection to the corpus striatum

Term
What is the result of a lesion of the subthalamus?
Definition

sudden, forceful involuntary movement in a contralateral extremity

 

the movement may be jerky (choreiform) or violent (ballistic)

Term
What does the epithalamus consist of?
Definition

habenular nuclei and their connections

 

pineal gland

Term
What is the habenular nucleus?
Definition
small group of neurons situated just medial to the posterior surface of the thalamus
Term
Where are the afferent fibers received by the habenular nucleus coming from?
Definition

received from the amygdaloid nucleus in the temporal lobe through the stria medullaris thalami

 

some of the fivers cross the midline to reach the havenular nucleus of the opposite side, these are havenular comissural fibers.

Term
What is the habenular nucleus responsible for?
Definition
integration of olfactory, visceral, and somatic afferent pathways
Term
What is the pineal gland?
Definition
small conical structure attached to the posterior part of the diencephalon by a stalk.
Term
What does the pineal gland contain?
Definition

superior part of the stalk contains havenular commissure

 

inferior part of the stalk contains posterior commissure

 

two cell types (pinealocytes and glial cells)

 

sympathetic fibers and blood vessels

 

NO NERVE CELLS

Term
What happens to the pineal gland over time?
Definition
calcification occurs with age - called brain sand
Term
Which part of the nervous system has the greatest functional importance?
Definition
hypothalamus
Term
Where is the hypothalamus located?
Definition

extends from the optic chiasm to the caudal border of the mammillary bodies

 

lies below the hypothalamic sulcus

Term
What is the hypothalamus composed of?
Definition
ascending and descending tracts and small nerve cells arranged in groups or nuclei
Term
What are the functions of the hypothalamus?
Definition
  • Controls emotional states
  • assists in regulation of fat, carbohydrate and water metabolism
  • influences body temperature
  • influences genital functions
  • influences sleep
  • influences food intake
  • in close relation to the pituitary - controls the pituitary hormone releases
Term
What does a lesion of the hypothalamus result from?
Definition

infection

trauma

vascular disorders

Term
What tumors can interfere with hypothalamic function?
Definition

craniopharyngioma or chromophobe adenoma of the pituitary

pineal tumors

Term
What are the most common abnormalities of the hypothalamus?
Definition
  • genital hypoplasia
  • genital atrophy
  • diabetes insipidus
  • obesity
  • disturbances of sleep
  • irregular pyrexia
  • emaciation 
Term
What issues would patients with lesions involving the insula have?
Definition
difficulty pronouncing phonemes in their proper order and usually produce sounds that are close to the target word but are not exactly correct
Term
What is found the interior part of the cerebral hemispheres?
Definition

lateral ventrical

masses of gray matter (basal nuclei

nerve fibers

white matter (fibers embedded in neuroglia)

Term
What is the basal nuclei?
Definition
masses of gray matter in the cerebral hemispheres
Term
What constitutes the white matter in the cerebral hemispheres?
Definition
nerve fibers embedded in neuroglia
Term
What are the basal nuclei?
Definition

collection of masses of gray matter situated within each cerebral hemisphere

 

Corpus Striatum

Amygdaloid Nucleus

Claustrum

Term
What is the Corpus Striatum?
Definition

"internal capsule" lateral to the thalamus

 

divided into 2 nuclei by a band of nerve fibers - caudate nucleus and lentiform nucleus

Term
What is the lentiform nucleus composed of?
Definition
globus pallidus and putamen
Term
The ____1____ nucleus is related laterally to a thin sheet of __2__ matter, the external capsule, that separates it from a thin sheet of __3__ matter, called the ____4____.
Definition
  1. Lentiform
  2. White
  3. Gray
  4. Claustrum 
Term
What is the function of the claustrum?
Definition
UNKNOWN
Term
What is located lateral to the Claustrum?
Definition
the capsule extrema - beneath the insula
Term
What is the function of the corpus striatum?
Definition

Receives afferent fibers from different areas of the cerebral cortex, the thalamus, the subthalamus, and the brainstem

 

Efferent fibers travel back to the same areas of the nervous system

 

Involved in muscular movement by controlling the cerebral cortex

Term
Where is the amygdaloid nucleus?
Definition

situated in the temporal lobe close to the uncus

 

part of the limbic system

Term
What can tumors of the caudate and lentiform nuclei cause?
Definition
severe motor or sensory symptoms on the opposite side of the body, due to involving the internal capsule.
Term
What is white matter composed of?
Definition
Myelinated nerve fibers supported by neuroglia
Term
What are the 3 types of nerve fibers found in the white matter?
Definition

commissural fibers

 

association fibers

 

projection fibers

Term
What do commissure fibers do?
Definition

connect corresponding regions of the two hemispheres

 

these are:

corpus callosum

anterior commissure

posterior commisure

fornix

habenular commissure

Term
What is the corpus callosum?
Definition

largest commissure of the brain that connects the two cerebral hemispheres

 

lies at the bottom of the longitudinal fissure

Term
What are the 4 divisions of the corpus callosum?
Definition

rostrum

 

genu

 

body

 

splenium

Term
What is the fornix composed of?
Definition
myelinated nerve fibers
Term
What does the fornix constitute?
Definition
constitutes the efferent system of the hippocampus that passes to the mammillary bodies of the hypothalamus
Term
What does the commissure of the fornix consist of?
Definition

transverse fibers that cross the midline

 

they connect the hippocampal formation of the two sides

Term
What do association fibers do?
Definition

connect various cortical regions within the same hemisphere

 

divided into short and long groups

Term
What are two examples of association fibers?
Definition

Uncinate fasciculus - connects motor speech area with temporal lobe

 

Cingulum - in cingulate gyrus; connects the frontal and parietal lobes with parahippocampal gyrus.

Term
What are projection fibers?
Definition

afferent and efferent nerve fibers passing to and from the brainstem to the entire cerebral cortex

 

pass between large nuclear masses of gray matter within the cerebral hemisphere

 

ie: internal capsule

Term
What is it called when the fibers of the internal capsule radiate in all directions to the cerebral cortex?
Definition
corona radiata
Term
Why are lesions of the internal capsule so frequent in vascular disorders?
Definition
a small hemorrhage can cause severe widespred effects on the contralateral side of the body
Term

What would result from a lesion of the anterior 2/3 of the posterior limb of the internal capsule?

 

posterior 1/3?

Definition

progressive spastic hemiplegia

 

sensory impairments of the opposite side

 

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