Neuro Flashcards
(99 cards)
1
Q
Major features of posterior part of brainstem
A
Pineal gland
Sup and Inf colliculus
Trochlear n
Dorsal columns
2
Q
Major features of anterior part of brainstem
A
Optic chiasm Pituitary stalk Cerebral peduncle CN 3-12 not 4 Pyramids Pyramidal dessiccation
3
Q
Where each nerve arrises in brainstem
A
Optic chiasm superior to pituitary stalk Oculomotor just above pons Trigeminal side of pons 6 7 8 ponto-medullary junction 9-12 medulla, but 12 separate
4
Q
Functional classification of cranial nerves
A
GSA- sensation from skin
GVA-sensation of viscera
GSE- muscles of eye and tongue
GVE- preganglionic para
SSA-vision, hearing
SVA- Smell and taste (nucleus solitaires)
SVE- muscles in chewing, facial expression
5
Q
Organisation of embryonic spinal cord
A
GSA and GVA dorsal
GVE and GSE ventral
6
Q
Organisation of embryonic brain stem
A
GSA and GVA lateral
GVE anf GSE medial
7
Q
GSE nuclei locations in brainstem
A
Oculomotor-midbrian
Trochlear
Abduncens- pons
Hypoglossal- medulla
8
Q
SVE nuclei location in brainstem
A
Trigeminal- pons
Facial- pons
Ambigus- medulla
Accessory- cervical spinal cord
9
Q
GVE nuclei location in brainstem
A
Edinger Westphal- midbrian
Salivatory- 3 in pontomedullary border
Vagus-pons
10
Q
Afferent nuclei location
A
SSA- vestibulocochlear- pons
GSA- Trigeminal- everywhere
GVA/SVA- solitarius- medulla
11
Q
Features of midbrain
A
Mickey mouse
Cerebral aquaduct
Substantia nigra
12
Q
Features of Pons
A
Transverse fibres
4th ventricle
13
Q
Features of medulla
A
4th Ventricle
Inferior olivary nucleus
Pyramid
14
Q
Features of lower medulla
A
Central Canal
Pyramid decussation
15
Q
Lateral medullary syndrome
Cause and symptoms
A
Thrombosis of veterbral artery or PICA
Vertigo- vestibular nucleus Ipsilateral cerebellar ataxia Ipsilateral loss of pain/thermal sense Contralateral loss of pain and thermal sense - spinothlalamic Difficulty swallowing Horner's Syndrome- symptoms fibres
16
Q
Oculomotor function
A
Movement of eyeball
Pupillary contraction
17
Q
Trigeminal function
A
General sensation
Mastication
18
Q
Facial function
A
Taste
Facial movements
Salivation
Lacrimation
19
Q
Vestibulocochlear function
A
Vestibular sensation
Hearing
20
Q
Glossopharyngeal function
A
Generla sensation and taste
Chemo+ baro
Swallowing and salivaiton
21
Q
Vagus function
A
Chemo+ baro
CVS, resp, GI
Visceral sensation
General sensation
22
Q
Accessory function
A
Sternocleidomastoid and trapezius
23
Q
Hypoglossal function
A
Movement of tongue
24
Q
Enlargements of spinal cord
A
C3-T2- cevical
T11-L2 Lumbosacral
25
Difference in spinal and cranial meninges
Spinal dura is not as closely associated with the bone and has extradural space, filled with venous plexus and fatty tissue
Useful for anaesthetic
26
Main spinal tracts
Lateral corticospinal
Dorsal columns
Spinothalamic
27
Injury to lateral corticospinal tract
Firstly spinal shock with using reflex and flaccid paralysis
Secondary reflexes become exaggerated and rigid paralysis
On same side as lesion
28
Injury to spinothalamic tract
Contralateral loss of pain in leg
29
Where each tract decussate
Lateral corticospinal- medulla
Dorsal columns- medulla
Spinothalamic- at level where enter spinal cord
30
Circle of Wilis
Vertebral arteries- Basilar- Posterior cerebral Arteries
Posterior communicating join these to middle cerebral which are joined to anterior cerebral arteries
Which are joined by an anterior communicating artery
31
Define stroke
Rapidly developing focal disturbance of brain function of presumed vascular organ with >24hrs duration
32
Define TIA
Rapidly developing focal disturbance of brain function of presumed vascular organ with <24hrs duration
33
Risk factors of stoke
```
Age
Hypertension
Cardiac disease
Smoking
Diabetes
```
34
What artery supplies which lobe
ACA- frontal, parietal
MCA- temporal
PCA- Occipital
35
Disturbance of ACA
Paralysis of contralateral leg
| Disturbance of intellect, judgement
36
Disturbance of MCA
```
Contrlateral hemiplegia (once side paralysed)
Contrlateral hemi-sensory deficits
Hemianopia- blind on half
Aphasia (don't understand or speak)
```
37
Disturbance of PCA
Homonymous hemianopia- loss of half on same side in both eyes
Visual agnosia- can't recognise
38
Types of haemorrhagic stroke
Extradural
Subdural
Subarachnoid- into space
Intercerebral- HT
39
Layers of neural tube
```
Neural canal
Ependymal Layer
Grey matter
White matter
Neural crest
```
40
Division of grey matter in later developing spinal cord
Alar plate- dorsal- interneurones
| Basal plater- motor neurons and interneurones
41
Structure of spinal cord
| layout
Central canal
Ventral and dorsal horn
White matter
42
Sections of developing brain
Prosencephalon
Mesencephalon
Rhombencephalon
43
Flexures of the developing brain
Cephalic
Pontine
Cervical
44
Development of the cortex
Neuroblasts are proliferating near the inner membrane
Some stay in the middle and form basal ganglia
Some migrate via radial glial cells
You end up with 6 layers of cells, with each having different types and functions
45
Types of regulation of cerebral blood flow
Neural
Chemical
Autoregulated
46
Neural control of CBF
Sympathetic- causing vasoconstriction
Para- facial nerve can cause slight vasoconstriction
Central cortical Neurones-Can release neurotransmitters that cause vasoconstriction
Dopaminergic neurones
47
How dopamingeric neurones cause constriction
Pericytes are associated and are contractile
The neurones innervate SM and pericytes causing consticrition
This is via aminergic and serotoninergic receptors
48
How CO2 causes vasodilation
H+ causes vasodilation but cannot pass through BBB
| However CO2 can and can be turned into H+
49
How NO causes vasodilation
It stimulates guanylyl cyclase which converts GTP to cGMP which causes vasodilation
50
Structures that don't have a BBB
Circumventricular organs
51
Formation of CSF
Ependymal cells surround capillaries, and secrete molecules into ventricles
52
Pathway of CSF
```
Lateral ventricles (choroid plexus)
3rd Ventricle
Cerebral Aqueduct
4th Ventricle
Subarachnoid space
```
53
Volume of CSF and volume formed
80-150mL
| 450mL/day
54
Function of CSF
Protection
Nutrition for neurones
Transport of molecules
55
Structure of BBB
Very tight juncitons
| Pericytes- but when these contract- more likely to escape
56
Examples of CVO
Median eminence region of the hypothalamus
Subfornical organ (SFO)
Organum vasulosum of the lamina terminalis (OVLT)
57
Plasma vs CSF
Lower in CSF-
K+, Ca, Aa, HCO3-
Higher in CSF-
Mg, CL-, H+
58
Broca's Area
Involved in producing speech
59
Wernicke's Area
Involved in understanding speech
60
Layers of dura mater
Periosteal
| Meningeal
61
Thalamic nuclei
Specific- primary cortical areas
Association- association cortex
Reticular- intrathalamic projections
Intralaminar- all cortical areas
62
Functional Cortical Areas
```
Primary motor cortex
`Primary somatosensory cortex
Primary auditory cortex
Primary visual cortex
Wernicke's area
Broca's areas
```
63
Thalamus association with RAS
Reticular foramen projects into thalamus to intralaminar nuclei
These are connected to all other nuclei which then can modulate activity of cortex
Increased activity coming through reticular formation the more activated the cortex becomes
64
Function of hypothalamus
Autonomic NS
Endocrine System
Behaviour
65
Close connections with hypothalamus
Olfactory
| Limbic
66
Pathway of sound conduction
| From outer ear to brain
Outer ear- external auditory meatus
Reaches tympanic membrane (eardrum) and 3 bones- stapes, incus and malleus
Sound is then transferred to the cochlear- then the vestibulocochlear nerve
Ipsilateral cochlear nucleus to superior olivary nucleus and inferior colliculus auditory cortex
67
Frequency and intensity of sound
Frequency- changing amount of compression/rarefraction between air particles
Intensity- difference in pressure between compressed rarefied air region
68
3 Ossicles
Stapes
Incus
Malleus
69
Eustachian tube
Tube linking nasopharynx to middle ear- to equalise pressure
70
Oval window
Membrane covered opening that leads from middle ear (in contact with stapes) to vestibule of middle inner ear
Pressure here greater than tympanic membrane
Amplifies the sound
71
Reissiner's membrane and Basilar's membrane
RM- Separates scala vestibule and scala media
| BM- separates scala media and scala tympani
72
Fluid filling the chambers in inner ear
Perilymph (low K high Na) and endolymph (low Na high K)
73
Conduction of sound in Scala vestiboli and tympani
Stapes vibrates onto oval window which sends signals down the perilymph in the Scala vestibule, this then travels to the helicotrema then back to the Scala tympani and then the round window
74
Properties of basilar membrane
Wider at apex and narrower at the base
Flexible at apex, stiff at base
On top of basal membrane- hair cells called stereocilia
75
Hair cells of basilar membrane
Movement of hairs either cause depolarisation or hyperpolarisation
If depolarised- transmits along nerve fibre
Hair cells project into endolymph
76
Tonotopy
Sound enters ear and travels along basilar membrane
Not responsive to low frequencies- since do not stimulate hair cells on basilar membrane very much
77
Testing for hearing loss
Anything above 20 decibels- progressively deafer
Test via conduction route- headphones
Or vibrate the skull- mastoid vibrator- to stimulate cochlear directly
If neither are working- suggests nerve damage
78
Types of hearing loss
Conductive- sound tramission in external/middle ear
Sensorineural- permanent due to cochlear/auditory nerve dysfunction
Auditory neuropathy spectrum disorder (ANSD)- dysfunction of transmission from IHC to lower brainstem- results in poor speech discrimination
Auditory processing disorder (APD)- dysfunction of central auditory pathways- resulting in difficulty processing sound
79
Transduction mechanism of hair cell
Upward movement- displaces stereocilia- opening K+ channels- K+ enters from endolymph- depolarisation- opens Ca2+ channels- causing glutamate release
Downward movement- K+ closing and hyperpolarisation
80
Tectorial membrane
Inside scala media
| Hair cells attach to this
81
Differentiation of pitch
Human range:20Hz- 20kHz
High frequencies- vibrate basilar membrane nearer to base
Low frequencies vibrate nearer apex
82
Organ of corti
Includes basilar and tectorial membrane, hair cells and supporting cells
83
How hair cells conduct impulses
Connected by tip links
Share location with ion channels, so when stimulated they pull on ion channel allowing potassium to enter
Active process allows negative stiffness
84
Aspects of active process of hair cells
Amplification- vibrates more to resonant frequency
Frequency tuning
Compressive nonlinearity- quiet sounds amplified more than loud ones
Spontaneous otoacoustic emission
85
Different hair cells
Inner- Afferent connections
| Outer- Efferent connections
86
Purpose of efferent fibres in hair cells
When activated frequency selectively and sensitivity is enhanced
87
Role of Outer hair cells
Perform amplifying role via electromobilisty
| Cell bodies shorten and elongates- allowing tectorial membrane to oscillate
88
Pathway of auditory neuronal conduction, and function of each complex
Cochlear nucleus- in brain stem, continue T stellate and bushy cells
Superior olivary complex- medial- where intreraural time difference is computed
lateral-where intensity difference is detected
Superior and Inferior Colliculus
Primary auditory cortex
89
Kinocillium and relevance to conduction
Cilia in ear
If transduction toward Kinocilia- depolarisation
If away- hyperpolarisation
90
Stimulation of hair cells in vestibular system
Deflection of forces to inertial resistance to acceleration and endolymphatic fluid rotation
91
Otolith Organs
Saccule and utricle
Saccule- in vertical plane-horizontal projecting hair cells
Utricle- horizontal plane- vertical projecting hair cells
92
Discharge of neurones in saccule during linear acceleration, being upright and static tilt
Upright- tonic discharge due to gravity constantly displacing hair
Static tilt- tonic discharge thats modulated, and will remain as long as the head it tilted
Linear acceleration- in horizontal plane- displacement spontaneous discharge
93
Semi circular canals
3 interconnected tubes in 3 planes
The horizontal, superior and posterior
Conented to cochlea
94
How hair cells in otolith organs are activated
Otoconia (crystals) is above a gel, so when acceleration occurs they move since they are heavier and displace the hair cells
95
How hair cells detect the fluid movement in semicircular canals
Movement of fluid moves the cupola in the ampulla
| This causes displacement of hair cells which activates the vestibular nerve
96
Labyrinths in inner ear
Bony- surrounded by petrous temporal bone filled with perilymph
Membranous- filled with endolymph
97
Vesibulo-ocular reflex
When head rotates the eyes rotate in compensation to the opposite direction
Aims to keep images fixed
98
Vestibulospinal Reflex
Lateral vestibulospinal tract- ipsilateral, motor to arms
| Medial- bilateral, motor to neck and nack
99
Balance disorders
Peripheral vestibular disorders- labyrinth and VIII nerve
| Central vestibular disorders-- CNS
