Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

DPT 736 Neuroanatomy > Brainstem: Internal Features > Flashcards

Brainstem: Internal Features Flashcards

1
Q

Main Components of Brainstem

A
  • cranial nerve nuclei and related
  • long tracts
  • cerebellar circuitry
  • reticular formation and related structures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Brainstem Lesions

A
  • cranial nerve abnormalities-tract deficits: sensory or motor determines deficit
  • long tract abnormalities
  • ataxia: unable to control body in space –> clumsy –> poor proprioception
  • reticular formation dysfunction: impaired level of consciousness, autonomic dysregulation: could be cardiac pulmonary-altered consciousness coma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Brainstem Sections

A
  • tectum: midbrain only-roof made up of superior and inferior colliculi dorsal to cerebral aqueduct
  • tegmentum: “covering” ventral to cerebral aqueduct in midbrain, ventral to 4th ventricle in pons and medulla, main bulk of brainstem nuclei and reticular formation
  • basis: ventral portion where large collections of corticospinal and corticobulbar tracts lie
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Orientation in Midbrain Axial Slices

A
  • midbrain…
  • cerebral aqueduct
  • periaqueductal gray surrounds cerebral aqueduct and does pain modulation
  • midbrain reticular formation
  • cerebral peduncles: substantia nigra and basis pedunculi
  • superior colliculus: rostral-oculomotor nuclei and red nuclei
  • inferior colliculi-caudal: trochlear nuclei and brachium conjunctivum (decussation of superior cerebellar peduncles)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Midbrain-Tectum

A
  • corpora quadrigemina…
  • superior colliculi (control of eye movement): afferents=occipital lobe (corticotectal fibers) and eye field of frontal lobe
  • inferior colliculi: afferents=ascending auditory fibers (lateral lemniscus) to thalamus, then to auditory cortex of temporal lobe
  • superior: eye movements
  • inferior: auditory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Midbrain-Tegmentum

A
  • substantia nigra: pars compacta produces dopamine
  • red nucleus: involved in motor control; afferents=cerebellum (superior cerebellar peduncles) and motor cortex
  • efferents=decussate and travel down rubrospinal tract-inferior olivary nucleus of the medulla at level of superior colliculi
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Orientation in Pons Axial Slices

A
  • pons “bridge”
  • 4th ventricle: separates tegmentum from cerebellum
  • lateral: middle cerebellar peduncle
  • ventral: basis pontis-corticospinal tracts, corticobulbar tracts, pontine nuclei-cerebellar function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pons

A
  • ventral portion…
  • pontocerebellar fibers (responsible for bulbous portion of pons) from the pontine nuclei (ventral pons), decussate and are carried through massive middle cerebellar peduncle to respective cerebellar hemisphere: pontine nuclei help with coordination of movement, receive corticopontine fibers (motor cortex) -coordination of movement
  • dorsal portion (tegmentum)…
  • superior cerebellar peduncle: consists mainly of ascending cerebellar efferents destined for red nucleus of midbrain and thalamus (coordination of movement)
  • middle-messages from pons to cerebellum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Orientation in Medulla Axial Slices

A
  • inferior cerebellar peduncles
  • pyramidal tracts
  • pyramidal decussation
  • anterolateral system and medial lemniscus
  • rostral medulla: inferior olivary nucleus; 4th ventricle
  • caudal medulla: posterior columns, posterior column nuclei
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Medulla-Caudal

A
  • caudal medulla: junction of medulla and spinal cord
  • decussation of pyramids
  • trigeminal sensory nuclei
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Medulla-Rostral

A
  • ventral surface of pyramids are still prominent
  • inferior olivary nucleus
  • vestibular nuclei
  • inferior cerebellar peduncle
  • cochlear medulla
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Inferior Olivary Nucleus

A
  • aids the control of movement
  • receives impulses from the sensory and motor cortices and red nucleus of the midbrain (rubrospinal-flexor muscle tone)
  • connected to cerebellum through inferior cerebellar peduncle
  • coordination and muscle tone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Vestibular Nuclei

A
  • receives afferents from vestibular nerve
  • links to nuclei that supply extraocular muscles (abducens, trochlear and oculomotor nuclei) through the medial longitudinal fasciculus-coordination of head and eye movements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Inferior Cerebellar Peduncle

A
  • olivocerebellar fibers
  • connections between vestibular nuclei and cerebellum
  • fibers of ventral and dorsal spinocerebellar tracts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Reticular Formation

A
  • net like
  • central core of nuclei that run entire length of brainstem
  • rostral reticular formation: maintain an alert conscious state-work functionally with diencephalon
  • caudal reticular formation: working with cranial nerves and spinal cord; motor, reflex, and autonomic functions; also helps to control tone, balance, and posture during movement-regulates CV systems, breathing, sleep-wake and being able to filter incoming stimuli to discriminate irrelevant background stimuli
  • treat patients with deficits here in closed environment-quiet rooms without much distraction or stimulation
  • complex matrix of neurons
  • widespread afferent and efferent connections with other parts of CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Reticular Formation and Tracts

A
  • receives collaterals from most ascending and descending tracts
  • descending reticulospinal tracts originate from the medullary and pontine nuclei of reticular formation: influence muscle tone and posture often times during movement
  • ascending fibers from the reticular formation receives information from multiple sensory sources and via the thalamus they help to activate the cerebral cortex and heighten arousal (reticular activating system)
17
Q

Reticular Formation and Afferents

A
  • receives a great variety of afferent information
  • integrates this information
  • disperses the efferents widely, influencing almost all parts of CNS: reticulospinal, reticulobulbar, reticulothalamic
18
Q

What Bypasses Retifcular Formation

A
  • auditory systems, visual systems, dorsal columns
  • can be inferred by startle to loud sound or sudden bright light
  • diffuse neuronal network in medullary and pontine reticular formation
  • respiratory center: control of respiration
  • cardiovascular center: control of cardiovascular function
19
Q

Safety Mechanism of Reticular Formation

A
  • bilateral destruction is generally required to abolish function-cross innervation
  • mediates consciousness, attention span, alerting responses, and sleep-wake cycle
  • in concert with forebrain…
  • control of breathing, pulse, BP, electrolyte imbalance, pupillary size and ocular movements, oxygen and carbon dioxide
  • GI and genitourinary system motility
  • coughing, sneezing, swallowing, vomiting, hiccupping, gagging, chewing, sucking, feeding
  • postural reflexes, extensor and flexor tone, vestibular reflexes, extensor tone and cortically induced movements
  • reduces transmission of pain impulses by inhibition of neurons in substantia gelatinosa
  • arnold Chiari malformation can compress brainstem resulting in some deficits
20
Q

Reticular Formation-Raphe Nuclei

A
  • NT: serotonin
  • ascending fibers to forebrain are involved with sleep
  • descending fibers to spinal cord are involved with modulation of pain
  • in animal experiments, stimulation of raphe nuclei and periaqueductal grey matter abolishes response to pain
21
Q

Destruction in Reticular Formation

A
  • destruction to rostral pontine reticular formation results in transitory loss of consciousness (short time)
  • destruction to rostral midbrain reticular formation results in permanent loss of consciousness
  • stimulation will arouse a sleeping animal
  • lesions in caudal half result in: respiratory apnea, hypotension, horner’s syndrome (damage to sympathetic pathways)
  • respiration: volitional breathing = pyramidal tract; automatic breathing = reticular formation
22
Q

Horner’s Syndrome

A
  • 3 cardinal symptoms
  • anhidrosis: inability to sweat normally
  • ptosis: drooping of eyelids
  • miosis: excessive constriction of pupils
23
Q

Odine’s Curse

A
  • pyramidal tract intact
  • reticular formation destroyed
  • respiratory arrest during sleep
  • must remain awake forever in order to breathe
  • aka central hypoventilation syndrome
  • congenital or acquired
24
Q

SIDS

A
  • defect may be in respiratory centers of medulla

- exact cause not known

25
Q

Bilateral Brainstem Lesion

A
  • destruction of vital centers

- respiration/cardiovascular

26
Q

Unilateral Brainstem Lesion

A
  • ipsilateral cranial nerve dysfunction (LMN)
  • contralateral UE/LE UMN signs
  • contralateral hemisensory loss
  • ipsilateral coordination deficit
27
Q

Lateral Medullary Syndrome (Wallenberg Syndrome)

A
  • ipsilateral: face pain, dysesthesia, anesthesia, dysphagia, dysarthria, ataxia, dysmetria, intention tremor, Horner’s syndrome
  • contralateral: loss of pain and temperature
  • general: nausea, vomiting, vertigo, hiccupping
28
Q

Bulbar Palsy

A
  • medullary

- paralysis of glossopharyngeal, vagus, and hypoglossal resulting in dysphagia and dysarthria

29
Q

Pseudobulbar Palsy

A
  • damage to corticobulbar tracts (medullary)
  • dysphagia, dysarthria, emotional lability, characterized by exaggerated laughing or crying
  • partial interruption of corticobulbar tracts
30
Q

Locked-In Syndrome

A
  • pontine
  • complete quadriplegia and bulbar/facial palsy due to complete interruption of both pyramidal tracts: infarct, neoplasm, trauma, or demyelination
  • ventral pons-bilateral corticospinal and corticobulbar tracts
  • patient is conscious and mentally intact but can only make vertical eye movements: vertical eye movements are controlled by region in tegmentum in rostral midbrain
31
Q

Decorticate Rigidity

A
  • damage to mesencephalon above red nucleus
  • disconnection of cortex
  • disinhibition of red nucleus: increased rubrospinal facilitation to UE
  • disruption of lateral corticospinal tract = no antagonism for extensor tone from vestibulospinal and pontine reticulospinal in LE resulting in extension
  • generally comatose
  • flexing in UE pointing to cortex
  • arm adduction and forearm pronation, flexion of wrist and elbow, extension of hips and legs
32
Q

Decerebrate Rigidity

A
  • further rostrocaudal deterioration of upper brainstem
  • red nucleus damaged
  • more severe than decorticate
  • vestibular system driven
  • what happens if decorticate rigidity continues (deterioration continues and damage gets worse usually resulting in death)
  • comatose
  • UE extended (adduction, wrist flexion and pronation)
  • hyperextension of trunks
  • LE extended/internally rotated
  • prominent plantar flexion
  • opisthotonos is severe hyperextension of trunk

DPT 736 Neuroanatomy (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions