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Year 2 - LCRS > Neuro > Flashcards

Neuro Flashcards

1
Q

Definition of Brainstem

A

‘That part of the CNS, exclusive of the cerebellum that lies between the cerebrum and the spinal cord.’

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2
Q

What is the primary function of the superior colliculus

A

important in the coordination of eye and head movements at the same time (think about watching tennis)

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3
Q

What is the primary function of the inferior colliculus

A

auditory reflexes - if there is a loud bang you tend to look in the direction of the bang immediately

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4
Q

What are the functional subtyoes of the cranial nerves?

A
  • General Somatic Afferent (GSA)
    • Sensation from skin and mucous membranes
  • General Visceral Afferent (GVA)
    • Sensation from GI tract, heart, vessels and lungs
  • General Somatic Efferent (GSE)
    • Muscles for eye and tongue movements
  • General Visceral Efferent (GVE)
    • Preganglionic parasympathetic
  • Special Somatic Afferent
    • Vision, hearing and equilibrium (only the cranial nerves)
  • Special Visceral Afferent
    • Smell (CN I) and Taste (comes from THREE cranial nerves that all go back to the nucleus solitarius)
  • Special Visceral Efferent
    • Muscles involved in chewing, facial expression, swallowing, vocal sounds and turning the head
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5
Q

Which CN Nuclei are SSA ?

A

Vestibulocochlear

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6
Q

Which CN Nuclei are GSA ?

A

Trigeminal

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7
Q

What is the function of the nucleus ambiguus?

A

SVE - Vocalisation and swalling

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8
Q

What might explain the following ssymptoms?

  • Vertigo
  • Ipsilateral Cerebellar Ataxia - problem with gait on the same side of the body as the lesion (broad-based gate - they tend to shuffle)
  • Ipsilateral loss of pain/thermal sense (face)
  • Horner’s Syndrome - loss of sympathetic innervation to the head and neck
    • Ptosis
    • Lack of sweating around the eye
    • Hoarseness
    • Difficulty swallowing
  • Contralateral loss of pain/thermal sense in the trunk and limbs
A

Lateral Medullary Syndrome

Caused by thrombosis of the vertebral artery or the posterior inferior cerebellar artery. (PICA)

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9
Q

How many paired spinal nerves are there?

A

31

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10
Q

At what level does the spinal cord end ?

A

L1/L2

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11
Q

Sensory fibres enter via dorsal or ventral ?

A

Dorsal

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12
Q

Motor fibres enter the spinal column via dorsal or ventral ?

A

ventral

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13
Q

What are the little protrusions of pia mater called that tether the spinal cord and hold it in the middle of the subarachnoid space

A

denticulate ligaments

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14
Q

Name two descending tracts Associated with voluntary movement. Where do thes decussate?

A

Lateral corticospinal tract

Anterior/Ventral corticospinal tract

Decussate in the medulla.

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15
Q

Which spinal tract is responsible for carrying afferent pain and temperature information ?

Where does it decussate?

A

Spinothalamic

Decussates immediately enters the spinal cord

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16
Q

Which spinal tract is responsible for carrying afferent information about touch, vibration and pressure?

Where does it decussate?

A

Dorsal Column (sometimes called the medial leminiscus pathway)

Decussated in the medulla

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17
Q

What are the two subdivision s of the dorsal columns and which carries information about upper/lower limbs?

A

Cueneate (medial) - arm, upper trunk

Gracile (lateral) - lower trunk

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18
Q

What might deficit might result form syrinomyelia ?

A

Syringomyelia is caused by an enlargement of the central canal called a syrinx.

Leads to loss of temperature sensation in the arms but not the legs.

The large space in the middle is selectively damaging the spinothalamic axons that are crossing over at the level of the lesion but it does not affect the fibres that have already crossed over and are travelling up in the spinothalamic tract

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19
Q

What arteries supply the brain anteriorly and posteriorly?

A

Anteriorly = Internal carotid

Posteriorly = Vertebral arteries

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20
Q

What links the sigmoid sinus to the cavernous sinus ?

A

The petrosal sinus

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21
Q

What si teh definition of stroke?

A

Rapidly developing focal disturbance of brain function of presumed vascular origin lasting more than 24 hours

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22
Q

What is the definition of a TIA ?

A

Rapidly developing focal disturbance of brain function of presumed vascular origin that resolves copletely within 24hrs

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23
Q

What proportion of strokes are due to infarction vs haemorrhage?

A

85%infarct 15%haemorrhage

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24
Q

Which arteries supply the following areas?

A
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25
Q

Disturbance of which artery would cause paralysis for the contrlateral leg?

A

Anterior Cerebral artery

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26
Q

Disturbance of which artery would cause paralysis for the contrlateral arm ?

A

Middle Cerebral artery

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27
Q

Disturbance of which artery will result in aphasia?

A

Left middle cerebral artery

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28
Q

Describe homonymous hemianopia

A

homonymous hemianopia, is hemianopic (half) visual field loss on the same side of both eyes

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29
Q

What is visual agnosia

A

an impairment in recognition of visually presented objects.

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30
Q

I haemorrhagic stroke, which sort might cause immediate effects and which might cause delayed?

A

`Extradural - immediate - arterial

Subdural - delayed - venous

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31
Q

Name the 3 bones in the middle ear and the membranes they are attached to.

A

Malleus attaches tympanic membrane

Incus attaches malleus and stapes

Stapes attaches oval window and incus

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32
Q

Which nerve supplies the lacrimal glands and which parasympathetic ganglion?

A

Facial nerve via pterygopalatine ganglion

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33
Q

What type of cells line the ventricles of the brain ?

A

Ependymal cells

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34
Q

What is the route of CSF ?

A

Lateral ventricle

Interventricular foramina

Third ventricle

cerebral aqueduct

Fourth ventricle

Subarachnoid space

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35
Q

What are circumventricular organs?

A

Areas of the brain where capillaries lack BBB properties

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36
Q

What organs make up the diencephalon?

A

Thalamus - either side of the third ventricle

Hypothalamus

Subthalamic nuclei

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37
Q

What is narcolepsy and what type of neurons might be involved in this?

A

Rapid onset of REM sleep often triggered by emotions

The orexin neurones in the lateral hypothalamus regulate sleep/wake cycle. Patients with narcolepsy do not have a orexin neuropeptide

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38
Q

What receptors sense hot temperature and chilli

A

TRPV

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39
Q

What receptors sense cold and menthol

A

TRM8

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40
Q

What are the most common cutaneous receptors and skeletal muscle receptors

A

Cutaneous - Polymodal C-Fibre (pressure, temp, chemical stimulus)

Skeletal muscle receptor - Chemoreceptor (for lactic acid)

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41
Q

What is the stimulus threshold?

A

The weakest stimulus detectable 50% of the time. Varies by body location and person-to-person.

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42
Q

What is a receptive field?

A

The area from like to stimulus elicits neuronal response. These overlap

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43
Q

Explain the concept of lateral inhibition

A

Activation of one neuronal unit inhibits activation of adjacent neuronal units. Mediated by Interneurones within the dorsal horn spinal-cord

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44
Q

What is it two-point discrimination?

A

Ability to detect two stimuli as distinct i.e. the minimum distance required between two stimuli in order to perceive they’re separate. Relies on:

  1. Peripheral mechano receptors
  2. Spinal posterior column
  3. Cortical function
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45
Q

What results from the loss of function mutation NaV1.7?

A

Born with an inability to feel pain- very rare

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46
Q

What type of receptor responds rapidly to neural adaptation?

A

Phasic receptors

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47
Q

What type of receptor responds slowly to neural adaptation?

A

Tonic receptors

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48
Q

What is neural adaptation?

A

If a stimulus of constant strength is maintained for a period of time the frequency of action potentials diminishes

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49
Q

What are the different nerve fibre types and their function?

A

α- Proprioception, somatic motor
β- Touch, pressure
γ- Motor to muscle spindle
δ- Pain, cold, touch

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50
Q

What is the function of C-type nerve fibres

A

Dorsal root- Pain, temperature, mechanoception
Sympathetic- Postganglionic sympathetic

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51
Q

Which nerve fibre transmits fast painful stimuli?

A

A-δ

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52
Q

What is the Gate Control Theory?

A

A non-painful stimulus can inhibit transmission of a painful stimulus. Ie large Aß fibres can reduce transmission of Aδ and C fibres within the dorsal horn

53
Q

What are the different types of pain? (6)

A

Nociceptive
Muscle
Superficial somatic
Visceral
Referred
Neuropathic

54
Q

What is Brown-Sequard syndrome?

A

Hemisectio nof the spinal cord. reduces sensation on one side and loss of pain sensation on the other.

55
Q

How does Ketamine cause ‘dissociative analgesia’?

A

Ketamine = NMDA antagonist. Long tem potenitation of NMDA = hypersensitivity to pain . Glutamate (acts on NMDA) is the major NT in the spinal cord.

56
Q

What is the WHO analgesic ladder for cancer pain relief?

A

1) Paracetamol, aspirin and ibuprofen
2) Codeine and tramadol
3) Morphine

57
Q

What is myalgia

A

muscular pain

58
Q

What is the wind-up phenomenon?

A

Where repetitive stimulation of wide dynamic range neurones induces increased evoked response and post-discharge with each stimulus

Related to neuropathic sensitization

59
Q

Describe neuropathic pain?

A

Pain in an area of neurological dysfunction. Has poor response to normal analgesic drugs. Can last after the area has healed completely

  • sharp
  • burning
  • electric shock
  • squeezing
60
Q

What is ALLODYNIA

A

Stimulus does not normally provoke pain

61
Q

PARAESTHESIA

A

Abnormal sensation but not normally painful eg tingling

62
Q

What is Complex Regional Pin Syndrome?

A

Severe form of neuropathic pain with neurogenic inflammation.
Overexpression of nociceptive endings
Treated with medication and spinal cord stimulation

Allodynia.
Temperature Asymmetry
Skin Colour Change
Sumomotor changes / oedema

63
Q

What drugs are used to treat neuropathic pain?

A

Antidepressants
Anticonvulsants
Opiod trial
Hybrid (Tapentadol)
Topical (e.g. Capsaicin)

64
Q

How do capsaicin patches work to treat neuropathic pain?

A

Capsaicin binds to TRPV1 receptor on nerve endings allowing influx of calcium. Capsaicin has direct toxicity to mitochondria, which reduces the number of nerve endings

65
Q

In the hierarchical organization of the motor cortex, what makes up levels 4, 3, 2, and lowest?

A

Level 4 - Assocaition cortex

Level 3 - Motor cortex

Level 2 - Brain stem
Lowest = Spinal cord (reflexive movements)

66
Q

What funciton does the Assocaition cortex have in integrating movement?

A

Contains the parietal and frontal cortex. Influences the planning and execution of movements

67
Q

What funciton does the Motor cortex have in integrating movement and what are the component parts ?

A

Primary motor cortex

Premotor cortex

Supplementary Motor Area

This is where voluntary movements are initiated

68
Q

What is level 2 and what is its role in movement ?

A

Brainstem - Integration of inputs from the vestibular systme, visual and auditory system

69
Q

What are Betz cells and wehre are they found?

A

Pyramidal cells - long axon

Found in 5th layer of grey matter. Where the descending motor mathways originate from

70
Q

What is the name of the descending motor pathway?

A

Corticospinal tract

71
Q

What are the 2 division of the corticospinal tract and what does each innervate

A

Lateral corticospinal tract - (decussates in the medulla) - Arms and Legs

Anterior cortical spinal tract (decussates spinal cord) - Trunk and proximal part of arms and legs

72
Q

What is broadman’s area 4 and what is its funciton

A

Primary motor cortex, also known as M1

Control of fine, discrete, voluntary movements.

73
Q

What is in Broadmann’s area 6? Where are they located and what are their function?

A
  • *Premotor Cortex**
  • Located anterior to the primary motor cortex
  • Involved in planning movements; regulates externally cued movments
  • *Supplementary Motor Area**
  • Also anterior to the primary motor cortex, but more medial
  • Involved in planning complex movements and programming sequencing of movements. Regulates internally driven movements (e.g. speech)
74
Q

What are the positive and negative signs of an upper motor neuron lesion?

A

Initial Loss of function (-)

  • Paresis: graded weakness of movements
  • Paralysis (plegia): complete loss of muscle activity

After a few weeks…
Increased abnormal motor function (+) (due to loss of inhibitory descending inputs)
- Spasticity: increased muscle tone
- Hyperreflexia: exaggerated reflexes
- Clonus: abnormal oscillatory muscle contraction
- Babinski’s sign

75
Q

What is Babinki’s sign

A

Normally if you stroke the plantar side of the foot = flexion

In upper motor lesion = extensor plantar response. Toes will fan and the big toe will go up

76
Q

What are the symptoms of a lower motor neuron lesion?

A
  • Weakness
  • Hypotonia (reduced muscle tone)
  • Hyporeflexia (reduced reflexes)
  • Muscle atrophy
  • Fasciculations: damaged motor units produce spontaneous action potential resulting in a visible twitch
  • Fibrillations: spontaneous twitching of individual muscle fibres, recorded during needle electromyography examination
77
Q

What is Motor neurone disease

A

Progressive neudegenerative disorder characterised. Can affect upper, lower mn or both .

78
Q

What structures form the basal ganglia?

A

A number of structures on top of the brainstem :

  • Striatum: caudate and putamen
  • Globus pallidus externa (GPe) and globus pallidus interna (GPi)
  • Substantia nigra pars compacta (SNc) and pars reticulata (SNr)
  • Subthalamic nucleus (STN)
79
Q

What is the funciton of the basal ganglia ?

A
  • Elaborating associated movements (e.g. swinging the arms when walking, facial expression matching emotions)
  • Moderating and coordinating movement (suppressing unwanted movements)
  • Performing movements in order
80
Q

What are the two pathways of the basal ganglia and which is inhibitory/excitiatory ?

A

Direct pathway - no project to STN excitatory

Indirect pathway - do project to STN - Inhibitory

81
Q

Name two disorders of the basal ganglia

A

Hypokinetic (parkinson’s disease)

Hyperkinetic (Huntington’s)

82
Q

What causes Parkinson’s and list some of the symptoms

A

Degeneration of dopamine neurons in Substantia Nigra

Bradykinesia - Slowness of movement / shuffling gait
Hypomimic face - expresionless
Akinesia - Difficulty in the initiation of movements
Rigidity
Tremor at rest

83
Q

What is Huntington’s disease?

A

Neurodegenerative genetic disorder
Abnormality in chromosome 4. Autosomal dominant
Degeneration of GABAergic neurons in the striatum (caudate first then putamen later)

84
Q

What are the main signs of Huntington’s disease?

A

Choreic movements (chorea): rapid jerky involuntary movements of the body. Hands and face affected first then legs and the rest of the body
- Speech impairment
- Difficulty swallowing
- Unsteady gait
Later on, cognitive decline and dementia

85
Q

What are the three horizontal lobes of the cerebellum?

A

Anterior
Posterior
Flocculonodular

86
Q

What are the three sagital zones of the cerebellum?

A

Vermis
Intermediate hemisphere
Lateral hemisphere

87
Q

What are the 3 funcitonal divisions of cerebellum

A

Vestibulocerebellar
Spinocerebellar
Cerebrocerebellar

88
Q

What is the function of th vestibulocerebellum

A

The flocculonodular lobe
Function:
- regulation of gait, posture and equilibrium
- coordination of head movements with eye movements

89
Q

What parts of the cerebellum make up the spinocerebellum? What inputs project into each area?
What is the function of the spinocerebellum?

A

Vermis and Intermediate hemisphere.

Vermis: Spinal afferents from axial portions of the body, trigeminal, visual and auditory inputs

Intermediate hemisphere.Spinal afferents from the limbs

Function:
Coordination of speech
Adjustment of muscle tone
Coordination of limb movements

90
Q

What part of the cerebellum makes up the cerebrocerebellum? What is the function of this area?

A

The lateral hemisphere
Coordination of skilled movement
Cognitive function, attention processing of language
Emotional control

91
Q

What results from flocculonodular/Vestibulocerebellar Syndrome?

A

causes syndrome similar to vestibular disease leading to gait ataxia and tendency to fall (even when sitting with eyes open)

92
Q

What are the syndromes of spinocerebellar syndrome ?

A

affects mainly the legs, causes abnormal gait and stance (wide-based)

93
Q

What are the symptoms of cerebrocerebellar Syndrome?

A

Damage affects mainly arms/skilled coordinated movements (tremor) and speech

94
Q

What cells make up the olfactory epithelium?

A

Bipolar olfactory neurons
Sustentacular cells
Basal cells

95
Q

What is the olfactory neural pathway

A

Olfactory bulb
♦
Olfactory tract
Medial Lateral
♦ ♦
Olfactory stria
♦ ♦
Orbitofrontal cortex Pirifrom
♦
Connections to brainstem and higher autonomic reflexes

96
Q

Where is the limbic system found and what structures does it compise?

A

A rim of cortex adjacent to the corpus callosum and diencephalon

Olfactory bulb
Hypothalamus
Amygdala
Hippocampus
Thalamus

97
Q

What is the limbic system responsible for?

A
  • Maintainance of homeostasis
    eg modulation of pituitary hormone release and initiation of feeding and drinking
  • Agonistic (defence and attack) behaviour
  • Sexual and reproductive behaviour
  • Memory (to previous situations modifies our response)
98
Q

What is the Papez circuit?

A

a neural circuit for the control of emotional expression

Mammilary bodies (hypothalamus)
(MTT MAMMILO-THALAMIC TRACT)
Ant Thalamic Nucleus

Cingulate gyrus

Hippocampus
(FORNIX )

MATCH

99
Q

Name four types of mechano receptors

A

`Merkel disc

Pacinian corpuscle
Meissner’s corpuscle
Ruffini ending

100
Q
A
101
Q

What and where is the locus coeruleus?

A

is a nucleus in the pons (part of the brainstem) involved with physiological responses to stress and panic.

102
Q

What structures make up the basal ganglia circuit

A
103
Q

What is another name given to lower motor neurons?

A

Alpha motor neurons/ventral horn cells.

104
Q

What are extrafusal and intrafusal skeletal muscel fibres?

A

Extrafusal - innervate skeletal muscle
Intrafusal - Skeletal muscle fibres that serve as specialist sernsory organs (proprioceptors) that detect amount and rate of change in length.

105
Q

How are the alpha motor neurons organised in the ventral horn?

A

Flexor muscles- posterior part of the horn
Extensor muscles- anterior part of the horn
Distal muscles- lateral part of the horn
Proximal part of the horn- medial part of the horm

106
Q
A
107
Q

Define a motor unit:

A

A single motor neuron together with all the muscle fibres that it innervates

108
Q

What are the 3 types of motor unit?

A
  • Slow (S, type I)
    Small dendritic trees, small diameter cell body.
    Small amount of force but don’t fatigue easily. Also postural muscles.

- Fast, fatigue resistant (FR, type IIA)
Moderate tension but fatigue resistant

- Fast fatiguable (FF, type IIB)
High tension. Easily fatigued.

109
Q

What are the 2 mechanisms by which the brain regulates how much force a single muscle can produce.

A
  • *Recruitment** - of more motor units. Smaller units are recruited first (generally slow twitch)
  • *Rate coding -** The rate of AP’s down a the nerves, generally slower units fire at lower frequencies.
110
Q

What is the size principle of motor recruitment ?

A

Smaller units are recruited first, hence why you can only use fine control at low levels of force.

111
Q

What fibre type changes can occur in muscle? (plasticity of motor units)

A

Training: Type IIB to IIA (fatiguable to fatigue resistant)
Spinal cord injury/microgravity: Type I to type II

112
Q

What muscel type changes occur with age?

A

Aging: loss of type I and type II fibres; preferential loss of type II fibres- larger proportion of type I fibres in aged muscle

113
Q

Which motor tracts are responsible for voluntary movement and what are these called?

A

1 Pyramidal tracts
1A) = Lateral corticospinal tract
1B) Anterior corticospinal tract

114
Q

Which motor tract is responsible for automated arm movements in response to changes in balance and what is this called?

A

Extrapyramidal tract 2A - Rubrospinal Tract

115
Q

Which motor tract is responsible for cordinating automated movements eg. in response to posture, and what is this called?

A

Extrapyramidal tract 2B - reticulospinal tract

116
Q

Which motor tract is responsible for regulating posture to maintain balance and what is this called?

A

Extrapyramidal tract 2C Vestibulospinal tract

117
Q

What are the components of a reflex arc?

A

1) Sensory receptor
2) Sensory neuron
(3 Interneuron -sometimes)
4) Motor neuron
5) Effector (muscle or gland)

118
Q

What is the time interval between stimulus and response of a single synapse reflex ?

A

~0.7ms

119
Q

What are the two waves seen in a Hoffman reflex when you stimulate a nerve and in which order do they appear?

A

Direct motor response going from the motor neurone that has been stimulated, directly to the muscle causing contraction

This is the M wave (motor wave)

A short time later you will see another response in the EMG and there will be another twitch

This is caused by the action potential in the sensory neurone going back to the spinal cord and exciting the motor neurone = H wave

120
Q

Name a polysynaptic reflex

A

Flexion withdrawal and crossed extensor

121
Q

What higher centres and pathways are involved in supraspinal control of reflexes?

A
  • Cortex- corticospinal (fine control of limb movements, body adjustments)
  • Red nucleus- rubrospinal (automatic movements of arm in response to posture/balance)
  • Vestibular nuclei- vestibulospinal (altering posture to maintain balance)
  • Tectum- tectospinal (head movements in response to visual information
122
Q

What is the function of gamma motor neurons?

A

Adjust the spindle so it remain taught thoroughout contraction, regardless of muscle length, thus maintaining senstivity. = GAMMA REFLEX LOOP

123
Q

What are the semicircular canals stimulated by?

A

Angular velocity = head rotation

124
Q

What are the otolith organs stimulated by?

A

Linear acceleratino of the head, and tilt.

125
Q

How do the semi-circular canals send signals about rotation ?

A

If head turned towards the right - Right horizonatal canal is activated and Left horizontal canal is disfalicitated.

If FWD tilt - anterior canal is activated.

If perfect horizonatal tilt = Ant. and POst. both activated on that side

126
Q

What is the vestibulo-ocular reflex?

A

Superior and medial neurons project to motor nuclei supplying extraocular muscles in order to stabilise the eyes when there is head movement

127
Q

What are the result of a lesion in CN VIII eg due to herpetic virus.

A

CN VIII supports tonic activity, so if it is lost on one side the remaining input from the other is the equivalent signal of a head turn

Results in:

  • Imbalance which righting reflex tries to correct
  • vestibular nystagmus - ie the eyes are continutally drifting to the side, then corrected.
128
Q

What test might be used to examina patient with labyrinth lesion?

A

Head rotation test. The head is rotated toward the side with the lesion . The patient’s eyes lose fixation, go with the head and after the movement the patien makes saccades back to the fixation point.

Year 2 - LCRS (9 decks)

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