Neuroscience Flashcards Preview

Neuroscience > Neuroscience > Flashcards

Flashcards in Neuroscience Deck (84)
Loading flashcards...
0
Q

Transtentorial herniation.

A

Can lead to duret haemorrhages due to stretching if arteries

Brain stem is pushed down by herniation causing shearing/ tearing of arteries

1
Q

Frontal eye field.

A

Brodmann’s area 8
Control of horizontal conjugate gaze
Located in middle frontal gyrus

2
Q

Halo sign.

A

Used to determine if there is CSF in nose fluid (after trauma)
Cerebrospinal rhinorrhea

3
Q

What neurons are made of pseudounipolar and bipolar types?

A

Pseudounipolar: all first order neurons of the spinal cord and most first order neurons from cranial nerves

Bipolar: cranial nerves I, II, and VIII

4
Q

Chromatolysis.

A

PNS axon regeneration
Occurs in first 24-48 hours following injury
Nissl bodies move to periphery
Nucleus moves away from axon hillock

5
Q

Axon repair.

A

24-36 hours - Wallerian degeneration (degeneration of distal portion of axon)

Chromatolysis

Slow axonal transport (1-5mm/day)

Neuronophagia occurs if axon does not recover

6
Q

Neuron supportive tissue.

A

Two types: fibrous connective and glial

PNS only has fibrous connective (includes Schwann cells)

CNS has glial cells and meninges are fibrous connective

7
Q

Lamina terminalis.

A

Forms from closure of anterior neuropores in 4th week

Forms front wall of thalamus

8
Q

Chronology of development.

A

Week 3 - beginning of neural plate
Week 4 - completion of neural plate
Week 4/5 - development of primary vesicles
Week 6 - development of secondary vesicles
Weeks 12-22 - development of corpus callosum
4th month - myelination begins
4th-8th months - development of sulci and gyri

9
Q

Periventricular leukomalacia.

A

White matter infarcts occurring during hypotensive episodes in premature infants

Can result in diplegia or quadriplegia

Potential cause of CP

10
Q

Rachischisis.

A

Non-closure of posterior end of neural tube (opening down spine)

11
Q

Holoprosencephaly.

A

One large ventricle and fusion of midline structures

Often associated with cyclopia

12
Q

Porencephaly.

A

Cyst formation typically post-infarction

Large growth of cyst can compress ventricles

13
Q

Lissencephaly.

A

Absence of gyri

14
Q

Tuberous sclerosis.

A

Distinction in white and gray matter is lost leading to tubers (enlarged firm white gyri)

Seizures and retardation

15
Q

Hydrancephaly.

A

Hemispheres are absent and replaced by two large CSF filled sacs.

16
Q

Arnold-Chiari syndrome.

A

Herniation of cerebellar tonsils into foramen magnum
Type I: herniation <3mm
Type II: herniation includes vermis (symptomatic)
Type III: herniation if brain stem and cerebellum outside of skull
Type IV: type III plus lack of cerebellum

17
Q

Dandy-Walker syndrome.

A

Very large dilation of 4th ventricle
Vermis is usually absent (sometimes no cerebellum)
Slow motor development and enlarged head

Treatment: positive pressure shunt

18
Q

Coloboma.

A

Congenital defect resulting in a fissure of part of the eye

Usually iris (unlikely to impair vision)

If in retina, can impair vision

19
Q

Heterochromia iridium.

A

Complete: one iris different from the other
Partial: part of one iris is a different colour

Affected iris lighter (hypopigmented): simple heterochroma
-Horner’s and Hirschsprung’s are often associated

Affected iris darker (hyperpigmented): Lisch nodules (NF1)
-commonly associated with Sturge-Weber syndrome

20
Q

Nonencapsulated receptors.

A

1) Free/naked nerve endings: pain sensation
2) Merkel’s discs: slowly adapting for pressure in hairless skin
3) Hair follicle receptors: free nerve ending wrapped around a hair follicle

21
Q

Encapsulated receptors.

A

1) Meissner’s corpuscles: rapidly adapting fine touch (two point discrimination, not homogenous distribution)
2) Pacinian corpuscles: rapidly adapting for vibration
3) Ruffini’s corpuscles: slow adapting stretch receptors in dermis of hairy skin

22
Q

Neuromuscular spindle.

A

Detects length of extrafusal muscle

Two types of axons wrapped around intrafusal muscle: annulospiral and flower spray

Aloha and gamma motor neurons

23
Q

Neurotendinous spindles/Golgi tendon organs.

A

A capsule of tendon fibres that are more loosely arranged and can be compressed - provides tension information

Provides and inhibitory effect - prevents too much tension on muscle

24
Q

ALS.

A

Degeneration of UMN and LMNs
Loss of voluntary control of muscles and bowel/bladder control
Eye muscles usually spared
Cognition and ANS usually intact

25
Q

Poliomyelitis.

A

Degeneration of LMNs resulting in flaccid paralysis and atrophy
Damage to anterior horns

26
Q

Where do the dorsal column and spinothalamic tracts synapse in the thalamus?

A

Ventral posterolateral nucleus (VPL)

27
Q

Location of nucleus gracilis and cuneatus.

A

2nd order neurons synapse at these nuclei in the caudal medulla

Axons then decussate and ascend as accurate fingers to the VPL of the thalamus

28
Q

Transverse myelitis.

A

Inflammation of the spinal cord causes by infection

Symptoms similar to SC transaction and LMN damage (usually at one segment)

Inflammation results in demyelination

Can present rapidly

29
Q

Tectospinal tract.

A

Reflex postural movements in response to visual stimuli

Receives input from optic tract in order to adjust body movement to eye movement

30
Q

Rubrospinal tract.

A

Inhibits extensors and facilitates flexors

Synapses in red nucleus, decussates, and descends ipsilaterally

31
Q

Vestibulospinal tract.

A

Facilitates extensors and inhibits flexors

Postural control and balance

32
Q

Reticulospinal tract.

A

Medial (pontine) reticulospinal: ipsilateral extensors
Lateral (medullary) reticulospinal: mostly ipsilateral flexors

Damage results in reflex contraction to innocuous stimuli

33
Q

Lower motor neuron symptoms.

A

Occur only at level of lesion:
Flaccid paralysis
Atrophy of muscles
Loss of reflexes
Muscular fasciculations
Muscular contracture (shortening of muscles)
Reactions of degeneration (decreased muscle response to electrical stimulation)

34
Q

Anterior cord syndrome.

A
Bilateral LMN symptoms at lesion
Bilateral UMN symptoms below lesion (not Babinski or loss of abdominal/cremasteric)
Occlusion of anterior spinal artery
CST and dorsal column spared 
Bilateral loss of spinothalamic
35
Q

Central cord syndrome.

A

Bilateral LMN symptoms
Bilateral UMN paralysis with sacral sparing
Bilateral loss of pain, temperature, and light touch with sacral sparing
Occurs after hyper extension injury in an individual with long-standing cervical spondylosis

36
Q

Brown-Sequard syndrome.

A

Ipsilateral LMN symptoms at level of lesion
Ipsilateral spastic paralysis, Babinski, and hyperreflexia below lesion

Ipsilateral loss of dorsal column
Contralateral loss of spinothalamic 1-2 segments below lesion
Complete sensory loss at ipsilateral level of lesion

37
Q

Familial spastic paraparesis.

A

Loss of all corticospinal tracts

Extension of leg and flexion of arms

38
Q

Subacute combined degeneration.

A

Caused by pernicious anemia
Degeneration of myelin
Paresthesias, leg stiffness, weakness, lethargy, fatigue, ataxia
Loss of dorsal columns and lateral corticospinal tracts

39
Q

Friedreich’s ataxia.

A
5-15 years old
Muscle weakness and ataxia 
Vision impairment, hearing loss, slurred speech
Aggressive scoliosis 
Diabetes mellitus
Enlarged heart
40
Q

Machoda-Joseph disease.

A
Weakness in arms and legs
Spasticity
Staggering, lurching gait, often mistaken for drunkenness 
Nystagmus, diplopia, polyuria
Difficulty with speech and swallowing
41
Q

Spastic bladder.

A

Damage above T12
Urination is involuntary, frequent and caused by spasms in lower limbs
Lacking sensation of full bladder

42
Q

Atonic (flaccid) bladder.

A

Direct injury to peripheral innervation of the bladder or lesion to cord around S2-S4

Retention with overflow incontinence

43
Q

Horner’s syndrome.

A

Interruption of the oculosympsthetic pathway

Can result from hypothalamic lesion, brain stem, plexus, or spinal cord lesion or compression or superior cervical ganglion

Ptosis, miosis, anhydrosis, enophthalmos, loss of ciliospinal reflex

44
Q

Damage to Edinger-Westphal nucleus.

A

Internal ophthalmoplegia (blown pupil)
Fixed and dilated pupil
Loss of accommodation reflex (cycloplegia)

45
Q

Adie’s pupil/Adie’s syndrome.

A

Damage to ciliary muscles or ciliary ganglion
Fixed and dilated pupil

If affects dorsal root ganglion = Adie’s syndrome
Decreased deep tendon reflexes, anhydrosis, postural hypotension, and unsteady heart rhythms

46
Q

Autonomic dysreflexia.

A

Spinal cord injury at or above T6 causing exaggerated sympathetic response from interruption of ANS control by higher centers

Severe headache, hypertension, tachycardia, fever, profuse sweating above injury level, and dry skin below

47
Q

Familial dysautonomia (Riley-Day syndrome).

A

Ashkenazi Jewish descent
Loss of autonomic and sensory ganglia neurons

Abnormal sweating
Unstable BP
Difficulty feeding
Progressive sensory loss

48
Q

Multiple system atrophy (Shy-Drager syndrome).

A

CNS degeneration
Orthostatic hypotension, anhydrosis, impotence and atonic bladder
Can show Parkinsonism symptoms

49
Q

Lambert-Eaton myasthenic syndrome.

A

Presynaptic defect in Ach release
Weakness of limb muscles but not bulbar muscles
Muscle strength improves with use

50
Q

Anaphylactic shock syndrome.

A

Severe allergic reaction: bronchoconstriction, system vasodilation, and severe hypotension

Epinephrine treatment:
Beta 1 - increases heard rate
Beta 2 - bronchiole dilation
Alpha 1 - peripheral vasoconstriction

51
Q

Weber syndrome.

A

Medial midbrain syndrome or superior alternating syndrome
Paramedian branch of PCA

CN III axons: ipsilateral ptosis, mydriasis and down and out eye

Corticospinal and corticobulbar

52
Q

Benedikt’s syndrome.

A

Short circumflex branch of PCA
Para median midbrain syndrome

Ocular deficits: CN III
Cerebellar ataxia (red nucleus)
Medial lemniscus (contralateral symptoms)
53
Q

Parinaud’s syndrome.

A

Dorsal midbrain syndrome
Lesion to superior colliculi
Usually caused by pineal gland tumor

Paralysis of upward and downward gaze
Pupillary disturbances
Absence of convergence

54
Q

Medial longitudinal fasciculus.

A

Extends throughout brain stem

Connects CN III, IV, VI, and VIII

55
Q

Medial inferior pontine syndrome.

A

Foville’s syndrome
Occlusion of branches of basilar artery

CN VI damage: medial deviation 
Corticobulbar damage (contralateral)
Corticospinal damage (contralateral)
Damage to pontine nuclei on one side and pontine fibres on the other - bilateral limb and gait ataxia
Medial lemniscus damage (contralateral)
56
Q

Lateral inferior pontine syndrome.

A

Occlusion of AICA

CN VII: ipsilateral facial paralysis, loss of taste anterior 2/3, loss of corneal and stapedial reflexes

CN VIII: unilateral central nerve deafness, nystagmus, nausea, vomiting, and vertigo

Cerebellar peduncles: ipsilateral limb and gait ataxia

Spinothalamic: contralateral

Descending sympathetic tract: ipsilateral Horner’s syndrome

57
Q

Lateral superior pontine syndrome.

A

Occlusion of superior cerebellar artery

Middle and inferior cerebellar peduncles: ipsilateral limb and trunk ataxia

Spinothalamic and spinotrigeminal: contralateral pain and temperature body, and ipsilateral for head

Descending sympathetic tract: ipsilateral Horner’s

Medial lemniscus: contralateral from lower limbs

58
Q

Locked in syndrome.

A

Infarction at the base of the pons
Corticospinal and corticobulbar
Quadriplegia and paralysis of lower CNs
Can only blink or move eyes vertically

59
Q

Central pontine myelinolysis.

A

Demyelination of central pons in patients being treated for hyponatremia or alcohol withdrawal

If treatment is too rapid - bilateral demyelination

60
Q

Lateral medullary syndrome.

A

Inferior alternating syndrome or PICA syndrome
Occlusion of PICA or vertebral artery

Nucleus ambiguous: CN IX, X, and XI dysphagia and dysarthria

Trigeminal: ipsilateral loss of pain and temperature on face

Vestibular nuclei/inferior peduncle: vertigo, nausea, vomiting, nystagmus
-ataxia

Spinothalamic: contralateral pain and temperature

Horner’s syndrome (ipsilateral)

61
Q

Medial medullary syndrome.

A

Inferior alternating syndrome or Dejerne syndrome
Occlusion of anterior spinal artery or vertebral artery

Contralateral hemiparesis (corticospinal)
Loss of dorsal column
Ipsilateral paralysis of tongue muscles (hypoglossal)
62
Q

Anterior commissure.

A

Decussatimg axons from CN I

Connection between amygdalas

Conveys some acute neospinothalamic pain information

63
Q

Uncus.

A

Part of temporal lobe

Primary olfactory area found here (area 34)

Portion that herniated in transtentorial herniation

64
Q

Tensor tympani.

A

Innervated by CN V (SVE)

Attached to malleous of the inner ear and decreases noise from chewing by inhibiting movement of malleolus

Damage could result in hypoacusis to low frequency sounds

65
Q

Bell’s palsy.

A
Swelling of CN VII in facial canal
Ipsilateral
Upper and lower facial paralysis
Loss of lacrimal ion
Decreased salivation
Loss of taste anterior 2/3 of tongue
Hyperacusis (stapedius muscle paralysis)
66
Q

Foster Kennedy Syndrome.

A

Meningioma of the olfactory groove

Compresses olfactory tract and optic nerve

Ipsilateral anosmia and contralateral papilledema (damage to ipsilateral optic nerve)

Loss of vision bilaterally (damage to one optic nerve)

67
Q

Gustatory ganglions and nerves.

A

Gustatory cells from taste bud synapse with first order neurons at these ganglia:

Nodose (CN X)
Petrosal (CN IX)
Geniculate (CN VII)

First order neuron goes to solitary nucleus in brain stem which projects to VPM, hypothalamus, amygdala, gustatory cortex, and hippocampus

68
Q

Caloric test.

A

Tests for brain stem damage

Normal: cool water in ear canal results in nystagmus towards opposite side and warm water results in nystagmus toward the same side

COWS = cool opposite, warm same

69
Q

Otosclerosis.

A

Fixation of the stapes

Age related

70
Q

Ménière’s disease.

A

Increased endolymph pressure

Fluctuating hearing loss
Roaring tinnitus
Recurrent spinning vertigo

71
Q

Acoustic neuroma.

A

Made of Schwann cells, benign, not age related

CN VIII is initially affected followed by CN V and CN VII

72
Q

Hyperacusis.

A

Stapedius muscle is attached to the stapes. Loud noises result in contraction of the muscle, dampening sound transduction normally.

Paralysis of muscle or damage to CN VII results in hyperacusis wherein loud noises are not dampened

73
Q

Ballismus.

A

Stroke induced
Involuntary flinging of contralateral limbs
Sub thalamus nucleus damage

74
Q

Sinemet.

A

L-dopa/Carbidopa combination

Carbidopa decreases degradation of L-dopa in systemic circulation

Lower doses = less side effects

75
Q

Most common movement disorders.

A

1) Essential tremor
2) Parkinson’s Disease
3) Dystonia (lentiform)

76
Q

Internal capsule.

A

Corticostriate and corticopontine go through anterior limb

Corticobulbar, corticospinal, corticofugal for extra pyramidal tracts, and 3rd order neurons from VPL and VPM go through posterior limb

77
Q

Anterior (genu) lesions.

A
Akinetic mutism (do not move or speak)
Tactile agnosia
78
Q

Posterior (splenium) lesions.

A

Alexia without agraphia

79
Q

Conduction aphasia.

A

Lesion to the arcuate fasciculus

Difficulty with repeating words or automatic lists (ABCs)

80
Q

Transcortical motor aphasia.

A

Area near Broca’s is damaged

Arcuate fasciculus is intact

Repetitive speech is intact

Like Broca’s

81
Q

Transcortical Wernicke’s aphasia.

A

Damage near Wernicke’s area

Speech is fluent and grammatical and repetition is good

Tend to substitute similar words often

82
Q

Balint’s syndrome.

A

Bilateral lesions to parietal and occipital lobes

Optic ataxia (inability to visually guide hands)
Optic apraxia (inability to voluntarily control gaze)
Simultagnosia
83
Q

Gerstmann’s syndrome.

A

Damage to area 39 angular gyrus

Contralateral heme- or quadrantinopia
Right-left confusion
Finger agnosia
Agraphia 
Dyscalculia