neuro important Flashcards

1
Q

what does the arterial system of the brain originate from ?

A

internal carotid - anterior portion = 80%

vertebral arteries - posterior portion = 20%

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2
Q

where are berry aneurysms most likely to form?

A

the junctions/connections between branches in the circle of Willis

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3
Q

roughly what area of the brain does the anterior cerebral artery supply

A

anterior and middle portion of brain

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4
Q

roughly what area of the brain does the middle cerebral artery supply?

A

lateral sides of brain

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5
Q

roughly what area of the brain does the posterior cerebral artery supply ?

A

posterior portion of brain - occipital and some of temporal lobe

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6
Q

what would be the effect of a lesion of the ACA

A

loss of contralateral motor and sensory functions of lower limbs

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7
Q

what would be the effect of a lesion of the MCA

A

contralateral motor and sensory functions of upper limbs and face (+ Broca’s aphagia)

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8
Q

what would be the effect of a lesion of the PCA

A

Vision (leads to opposing side homonymous hemianopia with Macular sparing)

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9
Q

what structures are found in the cavernous sinus

A
(O TOM CAT)
Oculomotor 
Trochlea 
Opthalmic 
Maxilliary 
Carotid (internal)
Abducens 
(Trochlea)
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10
Q

what is cranial nerve 1 and what is its function

A

olfactory

smell

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11
Q

what is the pathway of CN I

A

olfactory epithelium -> olfactory bulb -> olfactory tract -> primary olfactory cortex (+ limbic system)

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12
Q

what type of fibre is CN I (olfactory)

A

sensory

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13
Q

what is CNII and what is it’s function

A

Optic

vision and sensory fibre for the pupillary light reflex and accommodation reflex

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14
Q

what type of fibre is CN II (Optic)

A

sensory

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15
Q

what is CN III and what is its function

A

Oculomotor

eye movement, pupillary light reflex and accommodation reflex

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16
Q

what type of fibre is CN III (oculomotor)

A

somatic motor
Oculomotor nucleus -> extraocular muscles except LR6SO4

autonomic motor/parasympathetic
Edinger-Westphal Nucleus -> ciliary ganglion -> ciliary muscles + sphincter pupillae

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17
Q

what is CN IV and what is its function

A

Trochlear

eye movement - superior oblique

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18
Q

what is the pathway of CN IV

A

Posterior Midbrain -> exits posteriorly -> loops round anteriorly -> SOF -> SO

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19
Q

what type of fibre is CN IV

A

motor

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20
Q

what is cranial nerve V and what are its branches

A

Trigeminal

opthalmic, maxillary, mandibular

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21
Q

describe the pathway of CN V

A

4 Nuclei along brainstem -> Trigeminal ganglion (Meckel’s cave) -> 3 branches

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22
Q

what kind of fibres make up CN V

A

Both
motor (muscles of mastication)
somatic sensory (pain, touch, temp, proprioception)

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23
Q

what are the functions of the V1-opthalmic branch of CNV

A

Somatic sensory: upper face, eyelids, lacrimal gland, and Ethmoid sinus
Autonomic sensory: sensory fibres for corneal reflex

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24
Q

what are the functions of the V2-maxillary branch of CNV

A

Somatic sensory: maxillary portion of face, upper teeth and lips, and nasopharynx

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25
Q

what are the functions of the V3- mandibular branch of CNV

A

Somatic sensory: mandibular region of the face, ant anterior 2/3 of the tongue, lower teeth and lips, external ear
Somatic motor: muscles of mastication, Tensor tympani, tensor veli palatini, Mylohyoid, Ant. Belly of DIgastric

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26
Q

what is CN VI and what are its functions

A

Abducens

eye movement - lateral rectus

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27
Q

describe the pathway of CN VI

A

Nucleus in pons anterior to facial colliculus -> exits through ponto-medullary junction -> SOF -> LR

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28
Q

what kind of fibres make up CN VI

A

motor

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29
Q

what is CN VII and what are its functions

A

facial
Sensory function: taste anterior 2/3 tongue, somatic sensation of external and middle ear
Motor function: Stylohyoid, Stapedius, post. Belly of Digastric, Muscles of facial expression
Autonomic motor function: motor - corneal reflex, lacrimal gland, Nasal gland, sublingual and submandibular salivary glands

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30
Q

what kind of fibres are in CN VII

A

sensory
motor
parasympathetic

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31
Q

what is CN VIII and what are its functions

A

vestibulocochlear

sound, balance

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32
Q

describe the pathway of CN VIII

A

Organ of corti/Vestibular system -> Vestibular ganglion, spiral ganglion-> CN VIII -> IAM -> into ponto-medullary junction lateral to 6 and 7

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33
Q

what is cranial nerve IX and what are its functions

A

glossopharyngeal
Sensory: Pharynx, soft palate, external ear, posterior 1/3 of tongue, carotid sinus and body
Motor: stylopharyngeus
Parasympathetic: parotid gland

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34
Q

what is the origin of CN IX

A

3 nuclei in medulla

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35
Q

what fibres does CN IX carry

A

both motor and sensory + parasympathetic

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36
Q

what is CN X and what are its functions

A

vagus
Sensory: aortic arch, thoracic viscera, larynx, Abdominal Viscera, External ear and epiglottis (taste)
Motor: muscles of soft palate (swallowing), pharyngeal muscles (swallowing), and Laryngeal muscles (speech)
Parasympathetic: Thoracic viscera, GI tract

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37
Q

what is the origin of CN X

A

medulla

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38
Q

what fibres does CN X carry

A

both motor and sensory + parasympathetic

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39
Q

what is CN XI and what are its functions

A

accessory nerve
Cranial: accessory to CN X in innervating the Pharyngeal muscles
Spinal: sternocleidomastoid, trapezius

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40
Q

what is the origin of CN XI

A

Cranial component: medulla; Spinal component: C1-C5

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41
Q

what type of fibres does CN XI carry

A

motor

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42
Q

describe the pathway of CN XI

A

Spinal component the brain via the Foramen Magnum -> meets up with the cranial component -> exits via the Jugular Foramen

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43
Q

what is CN XII and what are its functions

A

hypoglossal

muscles of tongue

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44
Q

what kind of fibres does CN XII carry

A

motor

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45
Q

what is the origin of CN XII

A

hypoglossal nucleus – medulla

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46
Q

what does the spinal trigeminal nucleus do

A

Receives sensory innervation from the face (CN V, VII, IX and X)

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47
Q

what is the nucleus ambiguus

A

Motor nucleus for muscles of the pharynx and Larynx (CN IX, X and XI)

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48
Q

what is the solitary tract nucleus

A

Taste nucleus (CN VII, IX and X)

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49
Q

describe the anatomy of the outer eye

A

Sclera (white part of eye)

Cornea (first point of refraction)

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50
Q

describe the anatomy of the middle eye

A

Iris: contains the sphincter pupillae, dilator pupillae
Choroid
Ciliary body: ciliary muscles and suspensory ligaments
lens

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51
Q

describe the anatomy of the inner eye

A

Retina: detect light
Outer pigmented layer: contains melnin
Inner neural layer – photoreceptors, light transduction, vit A storage

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52
Q

action of lateral rectus

A

abduction

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53
Q

action of medial rectus

A

adduction

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54
Q

action of superior rectus

A

elevation, adduction and intorsion

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55
Q

action of inferior rectus

A

Depression, Abduction and extorsion

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56
Q

action of superior oblique

A

Intorsion, abduction, depression

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57
Q

action of inferior oblique

A

Extorsion, abduction, Elevation

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58
Q

what are the 2 synergistic pairs of eye muscles

A

SR + IO

IR + SO

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59
Q

what is the effect of a CN III palsy

A

Depression and abduction of eye (down and out)

Eye lid drooped down

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60
Q

what is the effect of a CN VI palsy

A

cant laterally rotate (abduct) eye

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61
Q

what is the effect of a CN IV palsy

A

eye extorted - appears slightly elevated

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62
Q

what parts of the ear are fluid or air filled

A
External ear (air-filled)
Middle ear (air-filled)
Inner ear (fluid-filled)
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63
Q

what are the aspects of the external ear

A

auricle, external acoustic meatus, tympanic membrane

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64
Q

what is the function of the auricle

A

directs sound into the external acoustic meatus

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65
Q

what is the function of the external acoustic meatus

A

Transmits sound into the tympanic membrane

Contains cerumen: prevents pathogens and insects from reaching the tympanic membrane

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66
Q

what is the function of the tympanic membrane

A

Vibrates in response to sound -> transmits vibrations to ossicles
Separates external ear from middle ear
Attaches onto the Malleus bone

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67
Q

what are the components of the middle ear

A

ossicles, muscles (stapedius, tensor tympani), eustachian tube, oval window

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68
Q

describe the direction of vibrations through the ossicles

A

Malleus -> Incus -> Stapes -> Oval window -> inner ear

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69
Q

what does the stapedius do

A

dampens the stapes to prevent excess vibration in response to loud sound

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70
Q

what does tensor tympani do

A

tenses the tympanic membrane to prevent excessive vibrations -> dampens loud sounds

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71
Q

what does the eustachian tube do

A

Tube: connects middle ear to nasopharynx and equalises pressure either side of the tympanic membrane -> Empties middle ear secretions into nasopharynx

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72
Q

what does the oval window do

A

transfers mechanical vibrations from the middle ear into fluid filled vibrations in the inner ear

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73
Q

what are the components of the inner ear

A

semi-circular canals, vestibule, cochlea

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74
Q

function of semi-circular canals

A

Detects changes in dynamic equilibrium

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75
Q

role of vestibule

A

Utricle and saccule

Detects changes in static equilibrium

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76
Q

components of cochlea

A

Scala vestibuli
Scala media/Cochlear duct- Organ of Corti
Scala tympani

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77
Q

what is the function of the basal ganglia

A

Execution of smooth movements – aka. Fine tunes movement plan
Stimulates desirable movement
Inhibits undesirable movement
Modulates movement

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78
Q

what makes up the striatum

A

caudate nucleus + putamen

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79
Q

what makes up the lentiform nucleus

A

globus pallidus + putamen

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80
Q

what are the 2 parts of the substantia nigra

A
Pars Reticularis (SNr)  
Pars Compacta (SNc)
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81
Q

what is the direct pathway of the basal ganglia

A

Stimulates desirable movement

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82
Q

what is the indirect pathway of the basal ganglia

A

Inhibits undesirable movement

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83
Q

what is the nigrostriatal pathway of the basal ganglia

A

Modulates both direct and indirect pathways => movement amplification

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84
Q

what causes Parkinson’s disease

A

hypokinetic
inactive substantia nigra compacta
overactivity of indirect pathway, underactivity of direct pathway

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85
Q

what causes huntingtons

A

hyperkinetic

destruction of cells of the indirect pathway, indirect pathway inhibition, decreased movement inhibition

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86
Q

what are the ascending tracts

A

DCML
Spinothalamic
spinocerebellar

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87
Q

what does the DCML convey

A

fine touch, proprioception, vibration

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88
Q

what does the spinothalamic tract convey

A

crude touch, pain, temperature

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89
Q

what does the spinocerebellar tract convey

A

unconscious proprioception

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90
Q

what are the descending tracts

A

corticospinal
corticobulbar
extra pyramidal tracts

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91
Q

what is the corticospinal tract involved in

A

conscious muscle movement

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92
Q

what is the corticobulbar tract involved in

A

voluntary movement of face and neck muscles

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93
Q

what are the extra pyramidal tracts involved with

A

coordination, posture and muscle tone

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94
Q

what do ascending tracts carry

A

sensory information towards the brain (4 orders of neuron)

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95
Q

what do descending tracts carry

A

motor information towards the muscles (2 orders of neuron)

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96
Q

describe the pathway of the DCML

A
  • Travels via the ipsilateral side to the nucleus
    1. 1st - Dorsal root ganglion, enters posterior column
    and ascends
    2. SYNAPSE to 2nd.
    3. Decussate at medulla
    4. SYNAPSE to 3rd in Thalamus
    5. Primary somatosensory cortex to 4th.
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97
Q

what does the anterior vs lateral spinothalamic tract convey

A

Anterior: crude touch and pressure.

Lateral: pain and temperature

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98
Q

describe the pathway of the spinothalamic tract

A
  1. 1st - Dorsal root ganglion, enter spinal cord and ascend together
    ipsilaterally for 1-2 segments.
  2. SYNAPSE. 2nd order decussate across anterior white commissure
    - Split into anterior and lateral.
    - Ascend on contralateral spinal cord.
    - DOES NOT decussate at medulla.
  3. SYNAPSE in Thalamus to 3rd order.
    - Fibres travel to primary somatosensory cortex.
  4. Synapse to 4th order which carry messages to various points in the
    cortex.
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99
Q

describe the pathway of the spinocerebellar tract

A
  1. First order: dorsal root ganglion into the spinal cord.
  2. Synapse to a second order neuron.
    - Splits and either crosses the spinal cord and goes up the
    ventral tract CONTRALATERALLY. Or doesn’t cross and
    ascends up the dorsal tract ipsilaterally.
  3. Dorsal into inferior cerebellar peduncle.
  4. Ventral into superior. Decussates within the cerebellum.
  5. BOTH END UP IPSILATERAL.
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100
Q

describe the route of the corticospinal tracts

A

anterior and lateral tracts. 10% stay ipsilateral, 90% decussate at medulla. Supplies musculature of the body

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101
Q

describe the route of the corticobulbar tracts

A

neurones terminate on the motor nuclei of the cranial nerves

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102
Q

what are the 4 extra pyramidal tracts

A

vestibulospinal, reticulospinal, tectospinal and rubrospinal

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103
Q

describe the route of the extra pyramidal tracts

A

the vestibulospinal and reticulospinal tracts do not decussate, providing ipsilateral innervation.
The rubrospinal and tectospinal tracts do decussate and therefore provide contralateral innervation

104
Q

what are the symptoms of Brown Sequard syndrome

A

loss of pain, temp and light touch on contralateral side (spinothalamic)
loss of vibration, motor, deep touch and position of ipsilateral side (Corticospinal/ DCML)

105
Q

what makes up a motor unit

A

an alpha motor neuron + extrafusal skeletal muscle fibres it innervates

106
Q

what do alpha motor neurones control

A

muscle contraction involved in voluntary movement

107
Q

what do gamma motor neurones control

A

muscle contraction in response to external forces acting on the muscle

108
Q

the smaller the motor unit ….

A

the finer the control

109
Q

what are intrafusal muscle fibres

A

regulatory unit surrounded by extrafusal fibres

110
Q

what is the role of intrafusal muscle fibres

A
- Sense stretch: monitors muscle length
and rate of change.
- Help to prevent overstretching of 
muscles.
- Type 1a and type 2 sensory fibres 
detect these changes.
- Innervated by gamma motor 
neurons that help keep the intrafusal 
unit taut so they can keep detecting 
change
111
Q

describe the stretch (myotatic) reflex

A

Stretch reflex: when sensory neurons in an intrafusal unit
detect over stretching.
type 1a - synapse and excite alpha motor neurones from same muscle - contraction
type 2 - synapse + inhibit alpha motor neurones of antagonistic muscle - relaxation

112
Q

what do golgi tendons detect

A

tension

113
Q

describe the role of the golgi tendons

A
- Have type 1B sensory fibres that are 
stimulated by the compression of 
muscle contraction.
- If there is too much muscle tension the 
golgi tendon organ will inhibit the 
muscle from creating any force (via a 
reflex arc), thus protecting you from 
injuring itself. As well as contracting the 
antagonistic muscle.
114
Q

what is the inverse stretch reflex

A

protects from the overload of muscle
if stimulated enough they will cause inhibition/relaxation of the contracting muscle and stimulation of the antagonistic muscle

115
Q

what is the axon resting potential

A

-70mV

116
Q

what do excitatory neurotransmitters do

A

Results in depolarisation of next neuron by bringing membrane potential closer
to threshold potential
- Generate excitatory post-synaptic potentials (EPSPs)
- Eg acetylcholine
- Increase the likelihood of a response

117
Q

what to inhibitory neurotransmitters do

A

hyperpolarisation
membrane potential decreased to further from threshold, harder for action potential to begin, generate inhibitory post-synaptic potentials (IPSPs)
e.g. GABA

118
Q

what does white matter contain

A

myelinated axons

119
Q

what does grey matter contain

A

cell bodies and no myelin sheaths

120
Q

what cells myelinate axons in the brain

A

oligodendrocytes

121
Q

what are commissures

A

tracts connecting one hemisphere to the other, cross the midline

122
Q

what are lemnisci

A

narrow strips of fibres

123
Q

what is a funiculi

A

rope or cord

124
Q

what is a capsule

A

sheet of white matter fibres that border a nucleus of grey matter

125
Q

what are nuclei

A

collection of nerve cell bodies within the CNS e.g. arcuate nucleus

126
Q

what are ganglia

A

collection of nerve cell bodies outside the CNS e.g. the dorsal root ganglia in the PNS
and some inside CNS that have capsule e.g. basal ganglia

127
Q

what are afferents

A

axons taking information towards the CNS e.g. sensory fibres

128
Q

what are efferents

A

axons taking information to another site from the CNS e.g. motor fibres

129
Q

what does reticular mean

A

where grey and white matter mix e.g. brain stem

130
Q

what are sulci

A

grooves

131
Q

what are gyri

A

ridges

132
Q

functions of the frontal lobe

A

voluntary movement on opposite side of body
dominant hemisphere controls speech (broca’s area) and writing
intellectual functioning, thought processes, reasoning and memory

133
Q

functions of the parietal lobe

A

receives and interprets sensations (pain, touch, pressure, size) and proprioception

134
Q

functions of temporal lobe

A

understanding spoken word (Wernike’s area), sounds, memory and emotion

135
Q

functions of the occipital lobe

A

understanding visual images and meaning of written word

136
Q

what are the grey matter structures

A

thalamus, hypothalamus, basal ganglia

137
Q

lentiform nucleus =

A

globus + putamen

138
Q

role of the thalamus

A

relay centre direction inputs to cortical areas

139
Q

role of hypothalamus

A

links endocrine system to brain & involved in homeostasis

140
Q

role of cerebellum

A

co-ordinates movement and balance

141
Q

how is the cerebellum attached to the brain stem

A

3 peduncles:
superior - midbrain
middle - pons
inferior - medulla

142
Q

how is the cerebellum separated from the dorsal brainstem?

A

4th ventricle - forms part of its roof

143
Q

what is the cerebellum made up of

A

folded cortex, white matter and deep inner nuclei

144
Q

how do cerebellar injuries present

A

slow, uncoordinated movements, intention tremor, weak muscles, nystagmus

145
Q

anatomy of the midbrain

A

tectum - superior and inferior colliculi
cerebral peduncle - tegmentum & crus cerebri
surrounds the cerebral aqueduct

146
Q

types of nerve cell

A

pyramidal, stellate, golgi, purkinje

147
Q

types of neuroglia

A

astrocytes, oligodendrocytes, microglia

148
Q

Neurulation

A

ectoderm - neural plate (3w) - differential mitosis - neural groove - detaches to form neural tube- neural crest cells laterally

149
Q

what do neural crest cells develop into

A

schwaan cells, pigment cells, meninges, bony skull, adrenal medulla, dorsal root ganglia, CN V, VII, IX, X, dermis

150
Q

which portion of the neural tube grows fastest

A

rostral - develops into spinal cord

151
Q

what are the 3 primary brain vesicles in week 5

A

prosencephalon (forebrain)
mesencephalon (midbrain)
rhombencephalon (hindbrain)

152
Q

what are the secondary brain vesicles present at week 7

A
  1. prosencephalon -> telencephalon + diencephalon
  2. mesencephalon
  3. rhombencephalon -> metencephalon + myelencephalon
153
Q

what does the telencephalon give rise too in the mature brain

A

cerebral hemisphere & lateral ventricles

154
Q

what does the diencephalon give rise too in the mature brain

A

thalamus, hypothalamus & 3rd ventricle

155
Q

what does the mesencephalon give rise too in the mature brain

A

midbrain (colliculi) & aqueduct

156
Q

what does the metencephalon give rise too in the mature brain

A

cerebellum, pons & upper part of 3rd ventricle

157
Q

what does the myelencephalon give rise too in the mature brain

A

medulla, lower part of 4th ventricle

158
Q

when does the neural tube usually close

A

week 4

159
Q

what happens is the spinal cord fails to close

A

spinal cord - spina bifida

cephalic region - anencephalus

160
Q

what are some developmental milestones

A
w3 - eye 
w10 - expansion, commissures 
3m - basic structures 
5m -myelination 
7m - lobes 
9m - gyri + sulci
161
Q

what does the corpus callosum do

A

fibre bundle which connects left and right hemisphere

162
Q

what percentage of neurons are in the cerebellum

A

70%

163
Q

functions of the hippocampus

A

limbic system
construction of mental images
short term memory
spatial memory and navigation

164
Q

what is anterograde tract tracing

A

transport from neural cell bodies to axon terminals

165
Q

what is retrograde tract tracing

A

transport from axonal terminals to neuronal cell bodies

166
Q

how do you detect brain activity

A

increased neural activity - increased neurotransmitters, need more O2 so blood - can be seen on imaging e.g. EEG

167
Q

role of glial cells

A

surround the soma, axon and dendrites of neurones and provide them with physical and metabolic support e.g. oligodendrocytes, schwaan, astrocytes

168
Q

role of astrocytes

A

help to regulate the composition of the ECF in the CNS by removing K+ and neurotransmitters (glutamate)
help form tight junctions - BBB

169
Q

role of microglia

A

specialised macrophage-like cells that perform immune functions in the CNS

170
Q

role of ependymal cells

A

line fluid filled cavities within the brain and spinal cord - regulate the production and flow of CSF

171
Q

what are the features of the blood brain barrier

A
endothelial tight junctions 
astrocyte end feet 
pericytes 
continuous basement membrane 
specific transporters
172
Q

what are circumventrular organs

A

lack the blood-brain barrier e.g. posterior pituitary

173
Q

how do ventricles and subarachnoid space connect

A

cisterns

174
Q

where does the CSF circulate

A

subarachnoid space

175
Q

how is CSF produced

A

by ependymal cells in the choroid plexus of the lateral ventricles

176
Q

what is hydrocephalus

A

abnormal accumulation of CSF in ventricular system

177
Q

what causes multiple sclerosis

A

the degeneration of myelin and development of scar tissue which in turn disrupts and eventually blocks neurotransmission along myelinated axons

178
Q

what are the 5 processes of synaptic transmission

A
manufacture
storage 
release 
interact with post-synaptic receptors 
inactivation
179
Q

what is temporal summation

A

input signals arrive from the same presynaptic cell at different times - summate - greater flow of ions into cell

180
Q

what is spatial summation

A

where 2 inputs occur at different locations in the post synaptic neurone

181
Q

name some examples of fast neurotransmitters

A

ACh
glutamate
GABA

182
Q

name some examples of neuromodulators - longer, slower response

A

Dopamine
noradrenaline
serotonin

183
Q

how do local anaesthetics work

A

interrupt axonal neurotransmission by blocking sodium channels

184
Q

what are cholinergic neurons

A

neurones that release ACh

185
Q

role of acetylcholinesterase

A

located on post and presynaptic membrane and rapidly destroys ACh, releasing choline & acetate
choline is transported back into presynaptic axon terminal for resynthesis of ACh

186
Q

what are the 2 general types of ACh receptors

A

nicotine -neuromuscular junction

muscarinic - brain and junctions of PNS

187
Q

role of noradrenaline

A

transmitter in the peripheral heart and CNS

affected by antidepressant drugs

188
Q

what is dopamine

A

important transmitter in basal ganglia

189
Q

what is the role of serotonin

A

has an excitatory effect on pathways that mediate sensations

190
Q

what is glutamate

A

main excitatory neurotransmitter

191
Q

what is GABA

A

main inhibitory neurotransmitter

192
Q

what is L-DOPA

A

precursor for dopamine - able to cross BBB - parkinson’s medication

193
Q

what is the human hearing range

A

20-20000 Hz

194
Q

what range is the ear most sensitive at

A

1000-4000 Hz

195
Q

what is sensation of the middle ear provided by

A

CN IX - glossopharyngeal

196
Q

what type of joints are found between the ossicles

A

synovial

197
Q

what substance is the cochlea duct filled with

A

endolymph (high K+, low Na+)

198
Q

how many rows of inner hair cells are there

A

1

199
Q

how many rows of outer hair cells are there

A

4-5

200
Q

describe the path of the cochlear branch of vestibulocochlear nerve (CNVIII)

A

cochlear nuclei -> superior olivary nucleus -> inferior colliculus -> medial geniculate body -> primary auditory cortex in Wernicke’s area

201
Q

where does the facial nerve CNVII exit the cranial cavity?

A

internal acoustic meatus behind the cochlea

202
Q

what does the vestibule apparatus consist of

A

3 semi-circular canals, the utricle and saccule

203
Q

what is the function of the semi circular canals

A

detect angular acceleration during the rotation of the head along 3 axis

204
Q

what is the function of the utricle and saccule

A

provide information about linear acceleration of the head, and about the changes in head position in relation to gravity

205
Q

what do rods detect

A

light and dark

206
Q

what do cones detect

A

colour

207
Q

what are the 3 layers of the tear film

A

anterior lipid
middle aqueous
posterior mucous

208
Q

what are the layers through which a photon must travel through the eye

A
tear film 
cornea
aqueous humour 
lens 
vitreous humour 
ganglion cell 
amacrine cell 
bipolar cell 
horizontal cell
cone & rods 
pigmented epithelium
209
Q

describe the blood supply of the eye

A

internal
9opthalmic, optic nerve) and external
(medial lid and orbit) carotid

210
Q

describe the somatic nervous system

A
innervate skeletal muscle 
single neurone between CNS and skeletal muscle cells
only excitatory 
conscious
only ACh
211
Q

describe the autonomic nervous system

A

innervate smooth & cardiac muscle, glands ect.
2 neurone chain
excitatory or inhibitory
involuntary
ACh before ganglion and ACh or noradrenaline after

212
Q

describe the sympathetic division of the autonomic nervous system

A

fight or flight
T1-L2, sympathetic trunks
pre = ACH + nicotinic receptors

213
Q

describe the parasympathetic division of the autonomic nervous system

A

pre = ACh + nicotinic receptors

effector cell = ACh + muscarinic receptors

214
Q

what are upper motor neurons

A

the descending pathways and neurones of the motor cortex

215
Q

what are the lower motor neurones

A

PNS, alpha motor neurones

216
Q

what is acute pain

A

less than 12 weeks

217
Q

what is chronic pain

A

more than 12 weeks

218
Q

what is nociceptive pain

A

pain that arises from actual or threatened damage to non-neuronal tissue and is due to the activation of nociceptors

219
Q

what is neuropathic pain

A

pain initiated or caused by a primary lesion/ dysfunction of the nervous system

220
Q

what are first order neurones/ primary afferent

A

enters through spinal or trigeminal nerve ipsilaterally synapses with 2nd order neuron in CNS

221
Q

what are second order neurons

A

cell body in spinal cord/ brainstem

decussates to other side of CNS and ascends to terminate at the thalamus

222
Q

what is a third order neuron

A

cell body in thalamus - projects to somatosensory cortex

223
Q

what are the afferent fibres of nociceptors

A

alpha delta fibres - thinly myelinates, touch, pressure, temp, fast pain
C fibre: unmyelinated, slow pain, temp, touch, pressure, itch - slowest conduction speed

224
Q

what is the insula

A

lies within the brain via the sylvian fissure

where degree of pain is judged - subjective

225
Q

what is the cingulate gyrus

A

medial aspect of hemispheres
linked with limbic system
emotion, learning and memory

226
Q

what is the periaqueductal grey

A

in midbrain

receives input from somatosensory cortex - reduced pain sensation in extreme stress

227
Q

what is substance P

A

peptide neurotransmitter involved in pain transmission , vasodilator , long lasting pain

228
Q

why do substantia nigra appear black?

A

neuramelanin that is produced as a by-product of dopamine production

229
Q

what do people with huntingtons lack

A

GABA

230
Q

what are the functions of the limbic system?

A

learning & regulation and translation of out emotional state into appropriate behaviour
connected via papez circuit

231
Q

what does the limbic system consist of

A

cingulate gyrus
hippocampus
parahippocampal gyrus
uncus, amygdala

232
Q

what is responsible for explicit memory

A

episodic - hippocampus & midbrain

semantic - frontal temporal lobe

233
Q

what is responsible for implicit memory

A

skills- cerebellum + basal ganglia
reflexes - cerebellum
emotional - amygdala

234
Q

what is the amygdala responsible for

A

emotional memory and output

responsible for fear

235
Q

what are the 2 inputs of the cerebellum

A
mossy fibres (middle peduncle) 
climbing fibres (inferior peduncle)
236
Q

what is the output of the cerebellum

A

purkinje cell axons

237
Q

what are the names and numbers of the vertebral column

A

7 cervical
12 thoracic
5 lumbar

238
Q

where are the dural venous sinuses located

A

between the periosteal and meningeal layers of dura mater

239
Q

what structure do the dural venous sinuses drain into

A

internal jugular vein

240
Q

where are the straight, superior and inferior sagittal sinuses found and where do they converge

A

found along the flax cerebri

converge at the confluence of sinuses

241
Q

what does the transverse sinus drain into

A

transverse -> sigmoidal -> internal jugular vein

242
Q

what does the cavernous sinus drain into

A

cavernous -> superior + inferior petrosal -> internal jugular vein

243
Q

where are the cerebral veins found and what do they drain into

A

subarachnoid space

drain into dural venous sinuses

244
Q

what supplies sensation to the middle ear?

A

glossopharyngeal nerve

245
Q

describe the pathway of sound

A

auricle -> external auditory canal -> tympanic membrane -> ossicles (malleus, incus, stapes) -> oval window -> scala vestibuli -> majority to cochlea duct, rest to scala tympani where pressure is relieved by the round window

246
Q

where does the basilar membrane lie

A

in the cochlea duct on the scala tympani surface

247
Q

how does the frequency differ at the base and the apex of the basilar membrane

A

base - thin, high freq

apex - wide, low freq

248
Q

what is the role of the inner hair cells in the cochlea

A

stereocillia extend into endolymph - convert movements into receptor potentials

249
Q

what is the role of the outer hair cells in the cochlea

A

stereocillia in tectorial membrane - sharpen frequency tuning
when bent- TIP links open, K+ channels open and influx in -> causes Ca2+ channels to open and influx in -> release of glutamate -> AP

250
Q

describe the path of the cochlea branch of vestibulocochlear nerve

A

cochlear nuclei -> superior olivary nucleus -> inferior colliculus -> medial geniculate body (via inferior brachium) -> primary auditory cortex

251
Q

what substance fills the vestibular system

A

endolymph

252
Q

describe how the semi-circular canals work

A

stereocilia are located at the capula near the ampulla

head rotation bends stereocilia which affects glutamate release

253
Q

describe how the utricle and saccule work

A

detect changes in gravity
saccule hair cells are at right angles to utricle hair cells
stereocilia covered by gelatinous substance with otoliths embedded

254
Q

describe the components of the direct pathway

A

cerebral cortex -> striatum -x internal Globus pallidus + SNr -x thalamus -> excitatory inputs to cerebral cortex

255
Q

describe the components of the indirect pathway

A

cerebral cortex -> striatum -x External Globus pallidus -x subthalamic nucleus -> SNr + internal globus pallidus -x thalamus -x inhibitory inputs to cerebral cortex